What’s important to know about lifestyle interventions and cancer care outcomes? Expert Dr. Jennifer Ligibel from Harvard Medical School discusses lifestyle interventions of physical activity and weight loss on cancer outcomes, controversy about body weight, and exercise levels during cancer treatment that show cancer outcome benefits.
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Lisa Hatfield:
How can lifestyle changes impact cancer care outcomes? The answer may be more crucial than you think. In this Patient Empowerment Network RESTORE program, we’ll connect with a respected expert on the ground floor of this research.
Dr. Ligibel, your research highlights the impact of physical activity and body weight on cancer risk and outcomes. Can you explain how exercise and weight loss interventions influence biomarkers associated with cancer risk and outcomes?
Dr. Jennifer Ligibel:
Absolutely. So this research is, I think, both really, really exciting and empowering for patients, because exercise and nutritional change are things that people can do themselves that don’t involve a prescription. But they can also be kind of confusing and leave people sometimes feeling like they’re not sure what the right thing to be doing is to support their long-term cancer outcomes. The truth is we do know that there are patterns that we see in society.
Like if you ask a lot of cancer patients, how much do you exercise and you track their weight. We see that people who exercise tend to have better cancer outcomes. So they tend to have a lower risk of cancer returning and a higher likelihood of surviving their cancer. For common cancers like breast cancer, colon cancer, prostate cancer, not as much evidence in some other cancers. We also know that people who keep their weight in a healthy range are less likely to develop cancer in the first place, and they’re less likely in some cancers, mostly the ones we talked about, breast, prostate, and colon to have their cancer return or die from cancer.
But what we don’t know is what aspect of lifestyle really drives these relationships, because the thing that’s complicated is that somebody who exercises more tends to have a little bit of a different dietary pattern than somebody who doesn’t. It’s not true for every single person. I’ve known marathon runners that live on Twinkies. But for the most part, people that exercise more are thinking more about their diets. They tend to weigh a little bit less, they smoke less. They may be going to do their screening mammograms and colonoscopies more often.
So it can be really tricky when you look at a large group of people and you just ask them what they’re doing and following them to make direct cause and effect relationships between one particular thing, like exercise or eating a particular food and their cancer outcomes. And this is one reason why my group at Dana-Farber, the research that we do really seeks to put people into interventions where we take a group of people that maybe aren’t exercising or they have a body weight that’s kind of above the ideal, and we help them to lose weight or to exercise more.
And we compare two groups of people that were the same at the beginning. One group took part in our program, the other didn’t. And then we’re able to kind of look more directly at whether these types of things affect their cancer outcomes, kind of what happens after their cancer is diagnosed. So we have some ongoing studies that are testing the effect of weight loss programs on cancer recurrence and breast cancer. We have some smaller studies looking at exercise and how that affects cancer. But the truth is we don’t a hundred percent know yet.
If we take a patient who’s not exercising or has weight in a certain range and we change that, is that going to have a direct effect on their cancer? We hope so, but that’s still something that we’re really studying. At this point, what we do know is that healthy lifestyle seems to be linked to lower cancer risk and better outcomes for people who’ve had cancer.
And I think the other thing that is really promising and hopeful is that there’s evidence that shows that even people that maybe didn’t have the healthiest lifestyle before being diagnosed with cancer, if they make some changes, they may have better long-term outcomes. So it kind of shows us that it’s not too late after cancer is diagnosed, but I think we’re still trying to really learn what are the particular factors for an individual person that are going to be most impactful to improve their cancer outcomes?
Lisa Hatfield:
Okay. Thank you. That gives cancer patients a lot of hope too, to know that going forward I can make some changes. In your randomized trials, how have you measured the effects of exercise and weight loss on cardio, respiratory fitness, and body composition in cancer patients? And what have been the key findings in their implications for patient care?
Dr. Jennifer Ligibel:
Absolutely. So we’ve done a lot of work in taking people who’ve been diagnosed with cancer and perhaps aren’t exercising regularly, or their diet is not as healthy as it could be, or their body weight is higher than the kind of there’s…a lot of controversy about the best body weight. But we, we kind of look at different levels of overweight and obesity and how they relate to health outcomes.
So we’ve looked at many different studies where we take people who might not have the healthiest lifestyle, and then we help them exercise more. We work, have them work with a coach or take part in a structured program. The first studies that we did really looked at, just how do you get people to make these changes when they’re going through cancer treatment or afterwards? Because there are a lot of extra barriers. We all know it’s not so easy to eat well or to lose weight or to exercise regularly at any point, but then you add cancer treatment to that, and it becomes more complicated.
So our first studies really just looked at how do you get people to do it? Is it safe? And we found indeed it was safe and that we could get large groups of people to engage in these programs. Not just people we enrolled at Dana-Farber, but people from all over the country. And that was really good to see that we could scale things that way.
Then we were interested in looking at some of the biomarkers you talked about, like what happens when somebody who hasn’t been exercising starts to exercise, or somebody whose body mass index is 27 or 30 or kind of in the higher levels showing that they have excess adiposity. What if they lose weight? What changes? So we’ve been able to show that people who exercise or lose weight have favorable changes in their metabolic hormones, favorable in changes in inflammation, which we know is something that relates to cancer risk.
And most recently, we’ve been able to show that exercise in particular has an effect on the immune system, both throughout the whole body and at the level where breast tumors form. So that’s been really interesting and helps to perhaps show us how is it that exercise could lower someone’s risk of cancer and really seeing how it activates the immune system. We’re also doing studies that then look at really big long-term outcomes, like whose cancer comes back and whose doesn’t. Those studies are really, really complicated to do. They involve enrolling thousands of patients, and they take 10 years to get the results.
And so, we’re still waiting for some of the outcomes of those studies. But the work that we’ve done so far shows that it’s safe for people to exercise and lose weight throughout their whole cancer journey, that it is also very scalable, not just to small groups of patients, but we can do this more broadly across thousands of patients. We’ve shown that when you make these types of changes, your metabolism improves, your risk of cardiovascular disease potentially decreases, then people feel better. We’ve done a lot of work with quality of life and fatigue and other side effects, and showing that when you make these types of changes the side effects of cancer therapy are often lessened.
Lisa Hatfield:
Okay, thank you. One quick follow-up question also as a patient. If you were telling me about exercise and how it might reduce inflammation, is that cardio or strength training or a combination of both? Do you have a recommendation on that for patients?
Dr. Jennifer Ligibel:
So, that is a great question and something that has been studied looking at different kinds of exercise. So there’s definitely value to both cardiovascular exercise, things like walking and running or swimming and to strength training. And that can be done using body weight. Things like squats and lunges, using weights, using machines. Strength training exercise is really important for maintaining muscle, and we know that a lot of cancer patients lose muscle, and that losing muscle is associated with losing function. So, doing strength training exercise is so important for maintaining your muscles.
A lot of the studies that have looked at how exercise relates to long-term cancer outcomes have primarily studied aerobic exercise, and that literature is really strong, that as little as walking three times a week can have benefits, long-term benefits in terms of cardiorespiratory health and perhaps even cancer-related outcomes. There’s an important place for both cardiovascular and aerobic exercise.
here’s a group, the American College of Sports Medicine, who tried to bring together all of the research from intervention studies. So studies where they took people and they put them on exercise programs to look at, well, what changes when you’re on an exercise program? And they looked at all these studies and tried to develop what’s called a fit prescription. So frequency, intensity, time, and type of exercise.
So to be able to tell people, “All right, what you need to do is 30 minutes of cardio three times a week, and that’s what’s going to help you feel better from a fatigue standpoint.” And so, they’ve worked out a couple of prescriptions for things like anxiety and fatigue that really are helpful in thinking about, well, how much do you really need to do to start to see a benefit? And in most of these studies, it was at least 90 minutes of aerobic exercise and a couple of strength training each week were kind of the minimal level of exercise where people really started to have benefit.
Lisa Hatfield:
Okay. That’s really helpful. Thank you.
Dr. Jennifer Ligibel:
Sure.
Lisa Hatfield:
Dr. Libel, how do you integrate quality of life assessments into your research on energy balance factors? And what role do these assessments play in evaluating the effectiveness of lifestyle interventions for cancer patients and survivors?
Dr. Jennifer Ligibel:
This is really important, because supportive care is designed to help people feel better. And if we are making people more active or changing their lifestyle in a way that doesn’t help them feel better, then we’re really not satisfying kind of the primary goal of supportive care interventions. And so, this is why we really make sure that we measure what are called patient-reported outcomes. So how does the patient feel as an integral part of the work that we do.
And so, most of the time these types of measurements are done through questionnaires where you ask people, how do you feel? How much does this side effect affect you? How much does fatigue impact your daily life? What about nerve-induced, what’s called chemotherapy-induced peripheral neuropathy? How much does that affect you? How much does that stop you from doing the things that you want to do? So we generally evaluate like, is the symptom present? And if it is, how much does it impact your ability to do the things you want to do? And I think that, when we see that people feel better that these side effects lessen as a result of interventions, that’s really what leads us to want to take things from being part of a research study to part of the standard care that we provide to our patients.
Lisa Hatfield:
That’s great. Thank you. You heard it here from the expert. Thanks for joining this RESTORE program. I’m your host, Lisa Hatfield.
