February 8, 2024 — Lorelei Mucci, professor of epidemiology at Harvard T.H. Chan School of Public Health, has spent her career seeking to understand why prostate cancer occurs, how it can be prevented, and what patients can do to improve their lives after diagnosis.
Q: How did you become interested in studying prostate cancer?
A: As a cancer epidemiologist, I have been committed to taking on some big unmet challenges in the field. I first became interested in the study of prostate cancer after realizing the public health impact the disease has for patients and their families. Across the world each year, 1.6 million people will be diagnosed with prostate cancer and it is the leading cause of cancer among men in 100 countries. It is also the leading cause of cancer mortality among men in 50 countries. In the U.S. each year close to 300,000 men will be diagnosed with prostate cancer and more than 30,000 will die from it. Thinking about ways that we can prevent this cancer from impacting so many people and their families has been something that’s really motivated the work that I do.
Q: Like many diseases, we know that the burden of prostate cancer doesn’t fall equally on different groups or people. Please explain.
A: One important feature of prostate cancer, and it’s driven some of my own research, is that certain groups of people seem more vulnerable both to the incidence and mortality of prostate cancer. In particular, Black men, or men of African ancestry have a much higher burden.
Moreover, from our own studies at Harvard Chan School, as well as through collaborations with researchers around the world, we have shown that prostate cancer has a really strong family history. If a man has a brother or father who’s had prostate cancer, his own risk of prostate cancer is considerably higher. And interestingly, if a man has a sister or mother with breast cancer, that is also associated with a greater risk. In fact, a lot of that risk associated with family history is due to inherited genetic factors. Patients with the top genetic risk of prostate cancer have an enormously elevated lifetime risk compared to somebody with a low genetic risk.
We think that part, but not all, of the disparity in prostate cancer in Black men may be due to a higher prevalence of these genetic factors. What’s also important is equal access to health care. For example, in Veterans Administration populations, where in theory, access to health care is equal, the outcomes from prostate cancer are equal between Black and white men. However, we know that in many populations there are delays in diagnosis, delays in treatment initiation, and different types of treatments that Black patients may receive compared to, for example, white patients. We know as well that there are social determinants of health that contribute to these differences. What we’ve been trying to do is really think across the prostate cancer continuum—from diagnosis to survivorship—about how to lower incidence and mortality and how to reduce disparities.
Q: Is it possible for people to lower their risk of getting prostate cancer in the first place?
A: To answer that question, I might first mention the clinical variability in prostate cancer—some patients have an aggressive, potentially lethal form of prostate cancer, while for many, prostate cancer has a low risk of metastasis. This clinical difference is important as we study risk factors for prostate cancer. As I mentioned, one of the strongest risk factors for prostate cancer is genetic risk, and we have found that 58% of variability in prostate cancer is due to inherited genetic factors. And these genetic factors equally predict the risk also of fatal prostate cancer.
Our studies have shown that a generally healthy lifestyle—engaging in regular physical activity, keeping a healthy body weight, not smoking, and adhering to diets that are higher in plant-based foods and lower in things like red meat—is associated with a lower risk of aggressive forms of prostate cancer. A healthy lifestyle and diet can also offset the elevated prostate cancer risk due to genetic risk. And not only are lifestyle changes going to lower risk, particularly of more aggressive forms of prostate cancer, they’re also good for cardiovascular health and reducing risks of other forms of cancer.
Q: Describe some of the work you’ve done to improve survivorship among prostate cancer patients.
A: Currently in the United States, there are over three million patients who are prostate cancer survivors. That’s a really large number of people that we need to be thinking about—what is the best evidence we can give them about healthy lifestyle and healthy diet, about medications they might be able to take in addition to the therapies they’re taking for their cancer diagnosis?
One particularly vulnerable group of patients are prostate cancer survivors whose cancers progress to metastatic disease. The diagnosis of a more aggressive form of cancer, as well as the types of therapies that a patient would get if they’re living with metastatic prostate cancer, can have broad effects on their quality of life and their risk of adverse events. But very little actually has been known about the survivorship experience for patients living with advanced forms of prostate cancer. So, we decided to start a global registry called IRONMAN. We’re recruiting 5,000 patients who have advanced metastatic prostate cancer, collecting really diverse types of information about them, and following them forward over time. We’re looking at biological markers that might help predict why some patients with metastatic prostate cancer can actually live and perhaps even thrive despite the fact that they have an aggressive disease.
Q: Any interesting results to share from your current research?
A: We’ve found that a healthy plant-based dietary pattern is not only important for survival, but it may actually improve aspects of quality of life such as urinary function, sexual function, and fatigue after cancer diagnosis.
Also, many students in our group have been interested in the role of social connections. The U.S Surgeon General labeled loneliness as one of the really big issues in public health, so we’ve been very interested in social connectivity in prostate cancer patients. We’ve found that individuals who are married [or have other types of social connections] seem to have better survival, even if they have metastatic prostate cancer and if the differences in some of the more aggressive features of the cancer are accounted for.
Q: You started a part-time position with the American Cancer Society last year. What are you doing in that role?
A: I am doing some really exciting work there that straddles my Harvard Chan School work. One aspect of cancer disparities that has been a key unmet need in prostate cancer is the lack of patient diversity in clinical trials. As I mentioned, Black men are twice as likely to die of their prostate cancer compared to white men. Despite that, there’s underrepresentation of patients who are racially diverse. As a result, we don’t know how well the therapies work for all patients. At the American Cancer Society, I have been engaged in driving forward several initiatives that can enhance the diversity of clinical trials.
photo: Kent Dayton