Conversations With Prostate Cancer Experts

Obesity, Exercise + Prostate Cancer

Dr. Stephen Freedland is a urologist at Cedars-Sinai in Los Angeles, California and the Director of the Center for Integrated Research in Cancer and Lifestyle, Co-director of the Cancer Genetics and Prevention Program and Associate Director for Faculty Development at the Samuel Oschin Comprehensive Cancer Institute.

Dr. Freedland believes in treating the whole patient, and not just a man’s prostate cancer.

Prostatepedia spoke with him about the link between BMI, exercise, and prostate cancer.

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Have you had any patients whose cases have changed how you view your role as a doctor or how you view the art of medicine?

Dr. Stephen Freedland: I think you go into medicine because you want to – at least for me – cure disease. That implies that there’s some state of perfect health. People come in to see me and they are not in a perfect state of health. You want to restore them to this perfect state of health. I now understand that there is no such thing as a perfect state of health. We perceive a perfect state of health to mean you have no diseases. However, you’re still at risk for certain diseases. Perfect implies you can’t do any better. I don’t think that’s the case. I think we can always do something better.

I changed from a physician whose goal was to cure disease to a life coach in many ways. I help move people from less healthy states to healthier states, but it’s not a black or white thing. I don’t cure disease and then go on to the next patient. I continue to work with them, hold their hand, be a counselor, a life coach, a shoulder to cry on, someone to slap a high five when they do have a success.

I had all those experiences yesterday in my clinic. A patient gave me a hug. He called me his angel, slapping high fives with another patient, and then one patient was practically in tears because he did not have such a good prognosis. To be able to ride the rollercoaster of life with patients is a phenomenal honor. It’s a lot of responsibility, but there is nowhere else in the world that I’d rather be.

That’s an interesting perspective. It’s more like seeing people when they’re healthy to help address diseases and issues as they come up rather than having people only come to you when they’re sick…

Dr. Freedland: An ounce of prevention is worth a pound of cure.

That’s a nice segue into my first question: what do we know now about the role of BMI, exercise, and prostate cancer risk?

Dr. Freedland: BMI has been much better studied. It is very clearly delineated that elevated BMI increases the risk of aggressive prostate cancer and increases the risk of dying of prostate cancer. That’s pretty incontrovertible at this point. You’ll see a study here and there that says the opposite, but the totality of the data is pretty convincing in that regard.

Exercise is a little harder to study because you can’t simply measure it the way you can measure someone’s height and weight and know what their BMI is. You need to ask them how much they exercise. Is it vigorous exercise? Is it nonvigorous? Are you doing an hour at a time? You can get 1,000 or 10,000 steps during the day, or you can go run on the treadmill and get 10,000 steps in a half hour. It’s very different.

Collectively, I would say the data seem to suggest exercise and particularly vigorous exercise may be beneficial to prostate cancer risk, but again, that is not nearly as codified nor as consistent and clear as the link we see between BMI and bad prostate cancer.

What impact does BMI or exercise have on risk of prostate cancer progression?

Dr. Freedland: Elevated BMI increases the risk of progression, recurrence, spread to metastatic disease, and death of prostate cancer whereas exercise, again, particularly vigorous exercise, seems to be preventive for progression. But, again, this is not as well studied and is based on a handful of exercise studies. The role of BMI is pretty well established.

A lot of men on androgen deprivation therapy (ADT) struggle with weight gain and muscle loss. What are the implications of this relationship between BMI and aggressive prostate cancer or exercise and aggressive prostate cancer for those men?

Dr. Freedland: As you said, ADT induces weight gain. You get muscle loss. There’s one study from our group that showed obesity at the time of ADT increases the risk of progression to castrate resistant disease. Surprisingly, it’s not been well studied. Let’s say you decide to go on a diet and not gain that ADT weight. We’ve actually shown a low-carbohydrate diet induces 25 pounds of weight loss despite being on ADT, so the weight gain is preventable. We do know that.

What we don’t know is impact of that weight gain on progression. Is gaining all that fat mass and losing muscle bad for your cancer? Intuitively, it should be. I mean, that just stands to reason from almost everything we know about prostate cancer and metabolism, but we haven’t proven it. We have not proven that if you can prevent those things, you can prevent or delay prostate cancer progression.

It certainly has an impact on cardiovascular disease, doesn’t it?

Dr. Freedland: Presumably but, again, it has not been studied in men on ADT. We do know exercise can preserve muscle function and quality of life. We know its impact on cardiovascular markers, but actually showing that exercise prevents cardiovascular disease in men on ADT has not been shown.

What we do know is that ADT will increase the risk of diabetes by about 40%. There’s data to suggest it may increase cardiovascular disease, but it’s controversial in that, if you look at really well done Phase III trials where men either got hormones or didn’t, you see no difference in cardiovascular deaths. Those are men on Phase III trials, selected to be healthy, and followed closely by their doctors. I think what we can say is, in highly selected patients, hormones are probably safe if you follow the patient closely, but in unselected patients, they probably do have cardiovascular effects.

That’s interesting what you just said: followed closely. Are you saying that people who are on clinical trials are just by nature of being in a clinical trial followed more closely than people who are not?

Dr. Freedland: Absolutely, I mean, there’s actually data to suggest that patients on clinical trials who are randomized to the control arm, i.e. standard of care, do better than patients not on the clinical trial who got the exact same treatment. Being on a trial, even if you don’t get that fancy experimental drug, still has benefits.

What does all this mean for patients? Should BMI be a priority for all men, including men who have prostate cancer?

Dr. Freedland: Correct. BMI is the strongest lifestyle link with prostate cancer. I see patients all the time ask me what should they eat. Should they take this supplement? Should they do that? Should they take this herb?

I say: just lose weight. That’s the one thing that we know. To me, it makes the most sense to focus on getting people to lose weight. How to lose weight is a challenge. Everybody has a difference of opinion. Part of it is picking a lifestyle and sticking with it. The word diet literally means way of life. The word is Greek in origin. We need to pick a way of life that’s sustainable, that’s going to work for you, and is going to help you to lose weight. The one common thread I see among all of the diets to a certain degree is reducing simple sugars—cookies, cakes, candies. There is not a diet that I’m aware of out there that says, “Nah, don’t worry about it. Eat all the cookies you want.”

You mean there is no chocolate cake diet?

Dr. Freedland: Correct. The low-fat, the whole-food plant-based folks will say eat all the vegetables you want. The low carb people will say eat all the meat you want. But all of them agree, even though they’re almost diametrically opposite, that cookies aren’t good.

What would you say about exercise? Would you tell men to prioritize BMI over exercise?

Dr. Freedland: To me, they go together. Do you know what the number one cause of death in men is?

Cardiovascular disease.

Dr. Freedland: Cardiovascular disease. What’s the number one cause of death in men with prostate cancer?

Cardiovascular disease.

Dr. Freedland: Cardiovascular disease. To me, if I can use a man’s cancer to scare him into eating right, losing weight, and exercising, I’ve probably done him a lot of good. Whether I’ve helped the cancer or not, in my mind, isn’t as important. Even if the exercise won’t help his prostate cancer, I’ve definitely done good from a cardiovascular point of view. To me, eating right and exercising go hand in hand. I don’t think you can focus on one over the other. Are you going to wear your pants today or are you going to wear a shirt? You need both, right? You’d look silly going around the workday without either one of those.

I guess it’s hard to lose weight without exercising.

Dr. Freedland: Amazingly, it’s not that hard to lose weight without exercising. Exercise is not a great way to lose weight. It’s a great way to get fit. It’s a great way to get healthy. Not a great way to lose weight. Not that it makes weight loss worse, but it actually doesn’t help weight loss much. Weight loss ultimately is about eating less.

Right, eating less than you spend, right?

Dr. Freedland: Correct, taking in less than you burn, and that’s where the whole-food plant-based diet comes in. You’re eating a lot of filling food that’s not calorie dense. It fills up your stomach and you feel full, even though you haven’t taken in a lot of calories.

You can also go to low-carb, which is very calorically dense. Fat and protein fill you up more than carbs, so you end up losing weight. There’s a lot of different ways to go about losing weight. There are general low fat diets. There’s Weight Watchers. There’s a lot of ways to lose weight. But exercise is something you do for your health, not to lose weight. The problem is that a lot of people start exercising to lose weight and then get frustrated and give up. You don’t exercise to lose weight. You exercise to get healthy. You eat less to lose weight.

Do you think discussions about BMI and exercise should be a part of every prostate cancer patient’s initial meeting with a doctor, whether he has low-risk or aggressive cancer?

Dr. Freedland: I think it should be a discussion with every patient at every visit regardless of the diagnosis. It should be part of a wellness visit, a hypertension visit, a high cholesterol or a BPH visit, or a prostate cancer visit. I think it needs to be integral. We need to not think of ourselves as prostate cancer doctors, or bladder cancer doctors, or whatever the case may be. We need to think of ourselves as doctors.

Most patients have more than one disease anyway. If you treat just the prostate cancer, then you’re ignoring the cardiovascular disease.

Dr. Freedland: Correct. It doesn’t mean we need to manage the cardiovascular disease and manage the blood pressure, but we need to be aware of it. We all went to medical school. But there’s more to a patient than his PSA and Gleason score.

Any final advice for men about obesity and prostate cancer?

Dr. Freedland: I always keep in mind the age-old adage: genes load the gun, but lifestyle pulls the trigger.

Join us to read the rest of this month’s conversations about diet, lifestyle, and exercise.