MS. DIANE REHMThanks for joining us. I'm Diane Rehm. Oncologist Siddhartha Mukherjee was a young exhausted medical resident when he discovered a book he says forever changed his understanding of medicine. The book was written by a physician practicing in the 1930s and '40. It lead Dr. Mukherjee to question common approaches to treating patients.

MS. DIANE REHMHe talks about this in his new book, titled "The Laws of Medicine: Field Notes From An Uncertain Science." Dr. Mukherjee joins me from an NPR studio in New York City. I invite you, as always, to be part of the program. Give us a call at 800-433-8850. Send an email to drshow@wamu.org. Follow us on Facebook or send us a tweet. Dr. Mukherjee, it's good to have you with us.

DR. SIDDHARTHA MUKHERJEEMy pleasure, thank you for having me.

REHMThank you. You know, Dr. Mukherjee, I've always believed that medicine was a combination of art and science. Now, you introduce law. Can you explain to me what it is you mean by adding laws to art and science?

MUKHERJEEWell, the quest in this book really began with a very simple idea and that was that, you know, when I read "Youngest Science," the book that you referred to, very influential book and not only for me, but for many other young doctors, I liked the word that was called the youngest science, medicine, the youngest science. So the inspiration in this book was, well, if it's a science, then what are its laws?

MUKHERJEEAll sciences have laws. And by laws, in medicine, I knew that it wouldn't be, you know, E is equal to MC squared or, you know, F is equal to MA, but it would be a more looser interpretation of what a law might mean, some kind of principles that a young physician might use as navigating posts to figure out how to deal with the complexity of medicine. And that's what I meant by laws, not sort of, you know, a codified law from physics.

MUKHERJEEBut some kind of inspiration, come kind of back bone, as it were, that I would find -- that I would like to find in medicine that would inspire me to think about medicine that way.

REHMAnd did you feel that those laws would not only inspire you, but would apply to other young medical students and physicians?

MUKHERJEEAnd patients, most importantly. So absolutely. I mean, you know, the search for law, I almost began this as a kind of whimsical proposition. I said, you know, as I said, if it's a youngest science, then what are the laws of this youngest science? And two points. One is, yes, absolutely, I was looking for things that were specific to medicine, per se, that would be sort of guiding principles, like laws, things that would stay true or remain true across the very broad context in which medicine in practiced.

MUKHERJEEYou know, from being the gastroenterologist in an operating suite to being a surgeon to being a young internist, et cetera. So that was one feature of it. But the second, which I sort of come to at the end of the book, is the idea that, well, you know, there may be many laws and one person's laws might be personal. So they were really more than -- it was partly kind of whimsical, if not sort of humorous take on the word laws, but the idea was to, again, find some codifying principles that would run across the discipline just like E is equal to MC squared runs across physics, whether you happen to be on the moon or whether you happen to be on Venus or whether you happen to be sitting in an NPR studio.

REHMAnd morality certainly comes into the concept of law.

MUKHERJEEAnd morality comes into the concept of law. Well, that's the other understanding of law. We also have human laws, which are not equations, but really are mechanisms to understand the way we operate across space and time. These human laws are, again, you know, they're not laws of nature, but they're ways that we use to interpret and understand our world. There's a lovely quote -- actually, the book begins with a quote that I love from "Harry Potter," from Hermione Granger who says, you know, that a teacher asks Hermione Granger, he says, well, are you learning these magical laws because you want to be trained in magic?

MUKHERJEEAnd Hermione Granger, sort of precocious as she is, says, no, actually, I'm learning these magical laws so I can do some good in the world. And so that idea appealed to me that, you know, you could have laws in medicine, not because you wanted to learn medicine, per se, but because you wanted to use these. You use these ideas as patients, as physicians, as practitioners of medicine, to do something about them, to do something to understand why medicine works the way it does, what is the skeleton behind medicine.

REHMAnd you've narrowed it down to, at least for yourself, three laws.

MUKHERJEEThose are the ones I came to, yes. So those are the ones that I ended up with, as it were, yes.

REHMTell us about those three laws.

MUKHERJEEWell, let me tell you the laws themselves and maybe we can spend some time on each one of them individually, but the first one is -- which I call Law One, a strong intuition is much more powerful than a weak test. Law Two is normals teach us rules and outliers teach us laws. And Law Three is for every perfect medical experiment, there is an equally perfect human bias.

REHMPerfect.

MUKHERJEEAll three of them were meant to be sort of provocative and sort of, you know, provoke some thinking.

REHMHelp me understand strong intuition. You're talking about a doctor's approach perhaps, not simply to the physical presentation or even the emotional presentation of a patient. You're talking about the intuition that a doctor must use to approach a patient.

MUKHERJEEAbsolutely correct. And, in fact, the way this came about, the first law, which is a strong intuition is much more powerful than a weak test, it came about from considering what's going on in the medical world today. So we are told, the newspapers inundate us with the idea that medicine is full of information, that there's information, you know, big data is everywhere. There's data everywhere. We're collecting data. You're using this data to make new decisions in medicine.

MUKHERJEEYou know, we will figure out, we will diagnose whether you have a risk for breast cancer using a genetic test and so forth so that -- or whether you have a risk for prostate cancer using another genetic test. There's a profusion of information about risk, about the way you act, you know. There's a kind of epidemiology of disease that is being reconstructed out of all this information. But what's interesting about this information is that this information really can only be interpreted in the context of who you are, who your personage is, who your personhood is, excuse me.

MUKHERJEEAnd you can't sort of put it in a vacuum and use these tests in a vacuum. It doesn't work. The only way that this system works, that this method works, if it works at all, is by using it in a way that's specific to a particular patient. So it is really -- this first law is really a mechanism to say that we've got to make all these tests individualized for individual patients and what better way do we have to individualize these tests for individual patients than, of course, using our intuitions, using the fact that we understand each person's individuality individually.

MUKHERJEEI'll give you the most absurd example of this. When I was a young resident, I was ordering tests for a person and, you know, there's a time in your life where you become so mechanical about these things, they're so mechanical about this knowledge that you sit there ticking off everything and I realized I had ticked off a PSA test on a woman. And that's absurd. That's an absurdity. Of course, a woman doesn't benefit from a PSA test. What would happen as a result of that is that test would go to some computer. The computer would pick that up and say, oh, you know, her PSA value is 1.25 and she has a low risk for...

REHMHer prostate value.

MUKHERJEEExactly, has 1.25 and so she has a low risk for cancer. But of course, that is a stupid thing to do without understanding it's an absurd example. But the idea is that our intuition that this is a woman that you're dealing with, not some kind of abstract person, must have something to do with the fact that we're ordering a test on this particular human being.

REHMIt does make me wonder whether tests in and of themselves, and as you say, they have so proliferated, whether doctors have come to rely too much on testing and simply not given themselves the freedom to rely on their own intuition. We must take a short break here. Dr. Siddhartha Mukherjee is with me. His new book is titled, "The Laws Of Medicine: Field Notes From An Uncertain Science." He's also the Pulitzer Prize-winning author of "The Emperor Of Maladies."

REHMShort break, your calls, your comments when we come back. Stay with us.

REHMAnd welcome back. If you've just joined us, Dr. Siddhartha Mukherjee is with me. His new book, titled "The Laws Of Medicine: Field Notes from an Uncertain Science." I want to go back, Dr. Mukherjee, to what we were just talking about, that is, that strong intuition. What happens when a patient comes to you and talks about what he or she is simply feeling? So often these days, when a patient reports in that way, the first thing a doctor does is to say, well, we'll have to order this and this and this and this test, which all add up enormously. And it seems to me that what you're urging doctors to do is to listen more carefully and to rely more intently on their own intuition rather than immediately ordering those tests.

MUKHERJEEThat's true or at the present modify that idea a little bit more. What I'm trying to say here is that the intuition is part of the test. The test does not exist outside. The test is a meaningless idea without the intuition. A test is a probability machine. That's -- there's nothing more to it. It moves. You feed it in an input probability and it feeds you out an output probability. That's what it is. A test is no more, nothing more than that. And what your intuition is, is it tells you what the prior -- what is the suspicion that this particular human being, under this particular circumstance, has a particular diagnosis.

MUKHERJEENow this idea is actually a very old idea. It's a very beautiful idea. And it was thought about by a great mathematician named Thomas Bayes, who worked -- who was a clergyman, actually. And he figured out something very important about the world and he asked a very simple question. He said, look, if you go and ask someone in a vacuum -- if you say, well, will the sun rise in the east tomorrow? And if the person was in a perfect vacuum, if he was a fool, they would flip a coin and they would say, well, if it's heads, it's going to be the east, if it's tails, it's going to be the west.

MUKHERJEEBut Bayes said, well, that's not how the real world works. If you ask a real human being how the world works, they use the prior knowledge of the last 365 days and the fact that the sun has risen in the east for the last 365 days tells you something more about what's going to happen tomorrow. So, in other words, a prior probability of an event tells you very, very, much about what's going to happen to the event in the future. The same principle -- it's called Bayes' theorem, he quantified this into a mathematical formulation -- the same principle applies to a medical test.

MUKHERJEEIf you base the medical test on no understanding of who the patient is, then what you get back often is garbage. You get back a PSA test for a woman. On the other hand, if you figure out that the particular individual may have particular risks, then you begin to modify your understanding of the risk and you get real numbers out.

MUKHERJEESo if you order a CAT scan -- I'll give you a very concrete example -- if you were to order CAT scans on the lungs of every single human being in the United States, including children, you'll find lots of lumps and bumps and masses everywhere. And if you biopsy those lumps and bumps and masses, which is expensive and time consuming and puts the patient at risk, you will find a few cancers. But the large proportion of these cases may be non-cancerous or benign lesions or things that the CAT scan picked up by mistake.

MUKHERJEEOn the other hand, if you took that same population and you said, well, okay, I'm only going to take people who have a very high risk for cancer. So, in other words, I'm only going to start with smokers. I'm going to use the same test. This test doesn't change. But all of a sudden, by changing the structure of the population, you've taken a perfectly useless test, and now, if you take those people, you'll actually find many more cancers and you'll prevent more cancers. So in other words, a test doesn't operate in a vacuum. It operates in the context of who you feed that test to. And that raises the question, well who knows or who do you decide -- how do you decide who you feed the test to? Well, it goes back to exactly what you said. It's your intuition. It's your understanding of who the patient is.

REHMDr. Mukherjee, I want to take you back to the winter of the year 2000, when you were in your first year of medical residency. And I ask to take you back there because I have long wondered about the sanity of young people who are in that residency.

MUKHERJEEMe, too.

REHMAnd I say it out of some understanding because of my daughter and son-in-law went through that and are, today, physicians. But it strikes me as though it's a crazy way to educate physicians.

MUKHERJEEIt is crazy. It's -- it redefines the word immersive, as in "The Emperor of All Maladies," my other book, I say, well, you know, people say that residency is immersive. What they really mean is drowning. That's what immersive means. But, well, you know, there are certainly important advantages to the system. It suspends you, immerses you, drowns you, in the life of medicine. It is -- it envelopes you with that idea. So, you know, it's all medicine all the time and there is a way, there's a rigor that comes with it, a scholastic rigor, an intellectual rigor, and also the capacity to have the stamina comes with it. There's important things about the continuity of the care of patients. So those are the advantages. But the concomitant liabilities are also large. People are sleep deprived. People have a hard time making personal decisions, making important decisions. And so there are bigger problems in that education system.

MUKHERJEEAnd, as you know, it's been challenged. People are -- were trying to change it. All of us are trying to change it. There are now hours, restrictions on hours and so forth, all for the better. That just -- I hope what that really means is that we'll have better intuition so that we can order better tests.

REHMI mean, you talk about almost being in a fog that entire time -- not only the sleep deprivation but the humanity deprivation. How do you make judgments in that kind of vacuum that you must be called on to make during those years of residency? I mean, it's almost torture for the young, would-be doctor and maybe not fair to that patient lying there in the hospital.

MUKHERJEEAbsolutely. Although, as I said before, there are some -- you can't throw the baby of residency out with the bath water of the fatigue. You have to see what the advantages and disadvantages are. There are some. They're important ones. It provides, you know, there is a long lesion in that immersion. There's a lesson in that rigor and a lesson in the kind of athleticism that decision making brings. But you're absolutely right. And, in fact, this has been studied extensively and the conclusions are quite clear. You know, we make decisions -- doctors make decisions in a compromised manner when they are deprived of sleep, et cetera.

MUKHERJEEMy only plea is that, you know, the medical system is terribly overburdened. It is terribly overburdened. The doctors who are running the medical system, the younger interns, we need to make them -- we need to value them. We need to value them deeply in our society. And that value is fraying. Once that value frays, we will be the ultimate losers because we will someday be patients ourselves. We've got to be able to value physicians again. We've got to be able to return their status as -- there's no other way to say it -- as heroes of our society.

REHMHowever, with the monetary pressures placed on physicians limiting the amount of time a physician can spend with a patient, how does the idea -- the law of using a strong intuition allow itself to be present, when you've got to rush this patient out in 12 minutes or whatever?

MUKHERJEEWell, that's what makes it a law, in the sense that, you know, whether you are -- whether you see a patient in two minutes or whether you see a patient in 15 minutes, whether you practice, you know, whether the patient is not even speaking to you because he or she is etherized on a table, the -- it will always be true that you can only interpret a test, as Thomas Bayes told us, you can only interpret a test based on the personhood of the human being.

REHMHmm.

MUKHERJEEAnd no matter how big the data set is, no matter how deep and how accurate the instrument is that allows you to measure the blood count in a nanodrop of blood, you still have to rely on who that individual patient is because that's a law. It is the nature of probability that the only way to interpret a probabilistic test is by understanding priors. We don't have a way out of it.

REHMYou use a phrase in the book, "The Laws of Medicine," therapeutic nihilism. Help me to understand that.

MUKHERJEEWell, it's a phrase that was really inspired by Lewis Thomas' work. And, again, now let me take you back, recreate the scene, as it were, in the 1940s and 1950s. This was a time when the available instruments in the pharmacopeia, the things that doctors could do, was extremely limited. I'll give you a couple of examples of that. You know, if you had heart failure in 1940, you -- the best you could do is you could bring your patient in -- the patient who had florid heart failure -- you could bring the patient in. You could put them under an oxygen tent, because oxygen was available. You could give them morphine to stop the terrifying pain in the heart.

MUKHERJEEYou know, the -- we don't even see that today. Some of us have seen this happen. When the heart fails, it causes a kind of terrifying syndrome of anxiety and pain. It's hard to describe. And the next thing you could do is you could take a needle and withdraw a pint or two pints of blood, because the heart -- the body was overloaded because the heart -- the pump wasn't working. So those were the things you could do.

MUKHERJEENow, move forward another 50 years, and we now have not just, you know, we have dozens of medicines that were diaries, that would take the blood volume off, that will add oxygen to, you know, that will make the heart rhythm stabilize, that will add -- take away the pain. In the worst-case scenario, as you know, we can transplant an entirely new heart or even an artificial heart, or an artificial valve into the heart. So what has -- what happened in the span of this 50-odd years is that the entire therapeutic modality changed. We changed every way we think about medicine because we got new techniques, new ways to manage complex diseases.

MUKHERJEEBut that happened -- for that to happen, we had to erase the pulp and the nonsense of the quackery that preceded all of this. And that happened in the 1940s and 1950s, when people like Lewis Thomas, people like -- and even earlier, doctors like William Osler said, wait a second. Let's throw away all the quackery that existed before that and let's just watch what happens...

REHMHmm.

MUKHERJEE...to disease as it progresses. And he called it therapeutic nihilism. He said, well, therapeutic nihilism is, let's just watch and see what happens when you take away all the quackery and watch the natural history of disease. And based on that, let's understand pathophysiology, why the heart fails, why you get cancer, why there's a pneumonia, and construct from step one, from the ground up, a new theory of medicine, a new kind of medicine that is based on rational precepts. That's what therapeutic nihilism achieved.

REHMAnd you're listening to "The Diane Rehm Show." I mean, couldn't you go way back in history to the earliest doctors in Greek history and say that medicine has been built slowly, slowly, slowly, with new techniques, new ideas coming generation after generation, and then reach that point in 1940 or '50 where you say, let's wipe out all the quackery, where perhaps that that has simply been a series of building blocks on which you finally reach a point where you understand, this is where we are now. This is what we've done in the past. Now we need to turn anew.

REHMThat would work, if there weren't terrible false leads and there were not branches leading you off into the wrong directions. You know, infections that we know are caused by bacteria were thought to be caused by miasmas. Who knows what that word meant, but it meant something. You know, the -- madness was called hysteria, because people thought that the uterus -- from which the word hysteria arises -- had sort of displaced itself, dislodged itself, particularly in women, and gone sort of crazy in the body like a balloon with the air being let off, you know, getting into your brain. So clearly there were a series of false ideas in medicine.

MUKHERJEEAnd, you know, many of them persist today. You know, future generations will laugh, perhaps, at us saying, oh, you know, the real reason we think X disease is caused by Y, you know, autoimmune diseases are caused, is because, you know, certain things happen. People will say, well, that was a crazy thing that they thought back then. But that -- the idea in medicine, like most sciences, is that the old has to be sometimes erased...

REHMHmm.

MUKHERJEE...to give ideas -- to give birth to the new. It -- sometimes a synthesis won't help. Because, in the sciences, there are things that are wrong versus right. There's a quest for truth. And you can't deny that quest. It is, you know, we're trying to look for natural things, natural laws, as it were. And sometimes the incorrect laws have to be scratched out and so that the space can be made for new ones.

REHMAnd making sure that what you're scratching out are the wrong ones and not something that could...

MUKHERJEEThat would be helpful.

REHM...that could be used...

MUKHERJEEThat would certainly be helpful.

REHM...in the future. All right. We're going to take a short break here. We have lots of phone calls waiting. When we come back, I'll open the phones and you'll have an opportunity to speak yourself with Dr. Siddhartha Mukherjee on his new book titled, "The Laws of Medicine: Field Notes from an Uncertain Science." Stay with us.

REHMWelcome back. Dr. Siddhartha Mukherjee is with me. He won the Pulitzer Prize for his book "The Emperor of All Maladies." He has a new one, it's a tiny book. It's titled "The Laws of Medicine: Field Notes from an Uncertain Science." Here's an email from Glen, who says, "Do you think doctors ask their patients enough questions about the patient's immediate physical environment in which they live? Perhaps not asking about a patient's environment might have the potential to miss underlying causes of disease and lead to misdiagnosis."

MUKHERJEEA very important question I think, and the -- let me just say -- start by saying that, you know, doctors don't ask enough questions, period. There was a study done, which I think is an incredible study, where they implanted a series of microphones to watch physicians as they started their examination. And how many words, Diane do you think a patient spoke before the doctor first interrupted them? Any thoughts?

REHMLike...

MUKHERJEEOn average.

REHM…30.

MUKHERJEENo, seven. I was going to try to interrupt you. So, well, that's an old fact, but it's coming down the particular question, yes, the physical environment. You know, I give a talk at TED, you can -- it's online, where I make the argument that, you know, there is -- you've got to be able to incorporate not just the patient who's sitting in front of you, but what the patient does in his or her life, the human being who inhabits his or her own life once they leave the hospital. There's an example that I gave in this book in which I was once -- I went to -- I was once asked to -- and, again, this was when I was a resident. There was a person with terrible emphysema, a man with terrible emphysema.

MUKHERJEEAnd the obvious thing to do was to prescribe home oxygen to prevent them from having terrible emphysema. And I went at the end of the day and I said, okay, I'm going to deliver home oxygen to you. And what's your address? And the man gave me an address. And the next day I got a phone call from a very irate delivery company saying, well, that's an auto mechanic in Boston. But the reality was, of course, it's a sad reality, the man was homeless, and how do you deliver home oxygen to a person who has no home? If you don't account for that person's extreme physical environment, he was embarrassed. He was embarrassed to tell me, to tell us.

REHMHe didn't want to tell you.

MUKHERJEEYeah. So that's an extreme example in which if you don't know -- again, it goes back to the first law. If you don't know who the person is, then giving them therapy, home oxygen without a home is a misnomer. It's a nonexistent therapy.

REHMAnd here's another email on a very important question. She says, "I am a family doctor, my husband a general internist. One issue we both deal with when trying to rely on intuition in our practice is that the payers' insurance, Medicare, et cetera, set up rules based on these test numbers. We are now being graded on how well we comply with the rules without any appreciation of individual nuances of our patients. This new system of grading is supposed to improve quality of care. Its downside is physician frustration, creating habits of relying too much on tests.

MUKHERJEEAnd that's precisely what law one is about. It is to diffuse or to remind ourselves that we'll only increase frustration and increase the cost if we don't understand how to provide tests. So, again, let me emphasize an important point. By intuition, I don't mean sort of loosey goosey kind of, oh, you know, the moon rose, you know, on the seventh planet yesterday, and therefore I feel as if -- by intuition I meant -- what I mean is understanding why a particular individual who may have tested positive for the BRCA1 gene increases or decreases her particular risk of acquiring breast cancer.

MUKHERJEEShould that woman who has a BRCA1 mutation have a mastectomy? Should she be treated with Tamoxifen and all its side effects? Should she watch and wait? Well, the answer is going to be that it's going to be -- it's going to be a combination of all of those things. Because unless you -- you know, you have to figure out a mechanism by which you understand what is happening to that individual patient, otherwise you'll prescribe a therapy for her that's not going to work for her.

REHMAll right. I'm going to open the phones, 800-433-8850. Let's go first to Cape Girardeau, Mo. You're on the air.

UNIDENTIFIED FEMALEGood morning. My question is regarding the ability of a student to be prepared at a broad based liberal arts education, and I'm referring to cultural difference with actinography, with sociology, et cetera. And would that help inform -- or help a candidate build this type of intuitive approach to medicine? Thank you.

MUKHERJEEAbsolutely. And, you know, that is part of the emphasis of humanistic education in medicine. And one of the things that we understand, we've understood very, very well over the years, is that medicine is, as Diane was just pointing out, both an art and a science. It's a humanistic science. It is the most humanistic science, because of course it's subjects, as it were. A subject, as it were, is human beings.

MUKHERJEESo the depth of actinography, the depth by which we understand the particular practices of individuals, their risks, their exposures, and more importantly, their desires, their fantasies, their lives outside the medical world is of absolute importance, and to understand what patients want, what they need, and how to treat them. And I can cite several examples of this. Some of them are very sort of hardnosed examples.

MUKHERJEEFor instance, the understanding of race and its interplay with your risk for a particular cancer is now becoming very, very clear. The understanding of important cultural practices and their changes in risk for certain diseases also similarly important, if you didn't understand those practices.

REHMGive me an example. Give me an example.

MUKHERJEESeveral examples. I'll give you a historic example, classic example. Which is that, you know, the idea that prions could cause disease. The idea that a protein that exists in an organism, if you consume that protein, can cause a disease, such as mad cow disease, famously. Really was brought into play because medical anthropologists and physicians went to faraway islands where as a result of chronic protein malnutrition among other things, women consume the dead.

MUKHERJEESo there's a kind of act of what we would call cannibalism, but of course it isn't because it's driven by extreme social and economic necessities. And this idea of Kuru, this disease, which was one of the first prion diseases, really came about because someone decided to actually go and find out why these women in their old age were succumbing to this terrible neurodegenerative disease. And that's the basis for understanding of disease like mad cow disease, and may be the basis for understanding common diseases like Alzheimer's disease.

REHMLet's go to Todd in -- sorry, Sandra in Todd, N.C. You're on the air.

SANDRAThank you, Diane. This is such a fascinating topic. I'm actually an integrated nutrition health coach. I love the discussion about doctors using more of their intuition when working with patients. I actually try to do that with my clients. And I'm curious what your guest thinks about the role of patients using their own intuition in terms of determining their health and their health outcomes. And I'll take my answer off the air. Thank you so much.

MUKHERJEESo the question is what is the role of patients using their own intuitions. Well, I think it should and will be a collaborative effort. Our intuitions are often wrong, and we have to acknowledge that. Even physicians' intuitions are often wrong. And that's the point of this. Law one says, you know, at least law one formulated says -- it doesn't say a strong intuition is sufficient to diagnose a disease. It says a strong intuition and a test, a strong intuition as a feed into a test, is important to diagnose a disease. That's what's important.

MUKHERJEESo I think that what I'm trying to suggest, again, is not relying on intuition alone or tests alone, but going back through the idea that Thomas Bayes discovered in the 18th century, what a beautiful idea that was, which is that intuition's prior probabilities, our understanding of illness is a mechanism to inform a good diagnostic test. I am fully a believer that we need tests, that we need good diagnostic tests because we lack them, but I also believe that we don't -- we can't interpret these tests without what I call intuitions. And that might be -- you know, that might be the patient's own experiences of illness.

MUKHERJEELet me tell you one thing that's kind of a funny story. When I ask -- this is actually -- when I sit and train residents myself, I mean, when I see patients myself, and the resident comes and presents a case, almost always my first question is, what does the patient think the problem is? And it turns out that 90 percent of the time they know what the problem is. They'll tell you, well, the reason that, you know, that my child is having asthma attacks over and over again is because he or she's getting exposed to smoke, because when he goes to his cousin's house every Saturday evening, you know, his uncle smokes, and that's why on Sunday morning we're in the hospital, you know, with an asthma attack. You know, we wouldn't be able to figure that out if you just hadn't asked.

REHMHere's a comment on our website posted by Carl. He asks, "Was the war on cancer a failure? Why or why not?"

MUKHERJEESo the war on cancer is far from a failure in my opinion. I think that the -- part of the misleading problem is that the word war is misleading.

REHMExactly.

MUKHERJEEIt -- the word war is misleading because in the 1970s we began to organize a concerted effort to understand cancer and to use our understanding of cancer to mount rational precepts to either prevent, cure or treat the disease. So that wasn't a war. Sciences don't operate through wars. They operate through, again, through solving puzzles. We began to solve the puzzle. We advanced the solution of the puzzle slowly, and we're now beginning to get the merits of solving that puzzle. It's a continuous process, and we've made several inroads and leaps in that. And that shows in the death rates from cancer.

REHMTell us about the patient you call Mr. Carlton, and his tricky diagnosis. You write about him in "The Laws of Medicine."

MUKHERJEESo Mr. Carlton is a patient that I saw when I was a resident myself. And he came to us with completely inexplicable weight loss, 20 pounds over the course of several months. You know, his -- the weight loss was so severe that his belt size -- he couldn't fit his belts anymore. His pants were falling off. He was a seemingly wealthy man, kind of a resident of a rich suburb of Boston. And, you know, everything being equal, the first thing we thought was cancer. And so he was tested up and down, left and right, colonoscopy, blood test, CAT scans for cancer, over and over again, and nothing came out positive. We were failing in all our tests.

MUKHERJEEAnd then, as I recount in the book, I was coming back home one evening after a long day at work, and I saw -- there's a coffee place in the hospital. And I saw an unusual conversation between Mr. Carlton, who was the resident of a rich suburb of Boston, and a man that I knew -- that I had admitted several weeks ago for heroin use, from a completely other part of town. And however you computed that, you know, Boston is a small town, but it's also very -- it's a town where patterns are put into place. You know, it's as if traditions are carried on to the extreme end.

MUKHERJEEAnd I kept thinking to myself, well, how could this violation of geography be going on? Why was this man speaking to someone that, you know, in the set geography of Boston, would somehow never seem to happen? It was a violation of that sort of -- of the set geography of Boston. And if you put two plus two together, all of a sudden it became obvious. What was really happening is that this guy, Mr. Carlton, was a heroin user. And the most likely reason for a heroin user to start suddenly losing weight in the 1990s was HIV. So we tested him for HIV, and he had fulmimant AIDS. And that's how the -- you know, it was, again, an intuition that tipped off that diagnosis.

REHMAnd you're listening to "The Diane Rehm Show." And let's go to Sara in Peoria, Ill., quickly, please.

SARAHi, Diane. Thank you so much for the show.

REHMSure.

SARAAnd Dr. Mukherjee, I just really appreciate the ideas that you're putting out there. I was diagnosed with breast cancer in 2011, and it came back shortly after just a few months actually, after my reconstruction. And when I brought it to my doctor's attention, the little lump, I was told by several different oncologists that it was scar tissue, because I'd had a double mastectomy, and cancer doesn't come back at the site after double mastectomy. So two years that cancer basically grew.

SARAAnyways, I just -- I feel it's so important that doctors listen to their patients. All along my intuition was telling me this is not scar tissue. It wasn't -- it just wasn't -- it didn't make sense. And it wasn't until it came out basically inflammatory, it just burst through my skin, and then I had to have an emergency surgery, that it was found out that it was cancer. So I had had the tests. I mean, I was being seen. I was making...

REHMYes.

SARA...every visit, so...

REHMUgh, I am so sorry.

MUKHERJEEI'm so sorry. I'm so sorry. And, again, that reminds -- it's the most visceral reminder that we just need to follow the logic that I try to outline in the book.

REHMDo me a favor, Dr. Mukherjee, and read for us page 72, the last page of your book.

MUKHERJEEDo you want me to start with "One last thought"? Is that...

REHMYes.

MUKHERJEE...where you want me to start?

REHMPlease.

MUKHERJEEYes. "One last thought, there is no reason to believe that there are only three laws of medicine. My laws are personal. They stood by me throughout my internship, residency and fellowship. They saved me from the most egregious errors of judgment. They helped me diagnose and treat the most difficult of the cases that I encountered in my practice. Every year I begin my teaching rounds at the hospital by explaining my version of the laws to the new medical residents. Each time I see a new patient in the wards or in the clinic, I remind myself of them. Yet, if there are other laws, I suspect they will also concern the nature of information and uncertainty at their very core.

MUKHERJEEDoctors, Voltaire wrote, are men who prescribe medicines of which they know little to cure diseases of which they know less in human beings of whom they know nothing."

REHMDr. Siddhartha Mukherjee, his new book is titled "The Laws of Medicine." Thank you so much for joining us.

MUKHERJEEThank you.

REHMAnd thanks all for listening. I'm Diane Rehm.