Obesity and prostate cancer are two very common diagnoses in older men, and several studies have found a relationship between excess weight and prostate cancer progression. “The diagnosis of cancer is an opportunity for a teachable moment for individuals to focus on improving their health to help them not just in their fight against cancer, but also in their general lives as well,” Dr. Jonathan Wright, Associate Professor in the Public Health Sciences Division at Fred Hutch, emphasized. Although a person’s exact causes for developing prostate cancer are not known, some of the established risk factors in men include age, genetics, race and ethnicity, and lifestyle. The treatments for prostate cancer aim at the removal or destruction of the cancer cells with minimal damage of the surrounding tissue. Current treatments range from surgical removal of the prostate (prostatectomy), radiation therapy to hormone, immuno- or chemo- therapy, or a combination of some of these methods.
Another key clinical strategy to practice is Active Surveillance (AS), which is mostly applied to men who are diagnosed with low risk and non-aggressive prostate cancer. This strategy involves monitoring prostate cancer without immediate treatment to avoid side effects from surgery and radiation therapy. The idea is to balance keeping the quality of life high for as long as possible and being ready to start treatment if the cancer starts to become more aggressive. However, up to one half of patients deriving a clinical benefit from AS are likely to eventually undergo definitive treatment, typically surgery or radiation. With the increasing numbers of men opting for AS as their management strategy for low-risk prostate cancer, identifying and understanding the factors that may drive cancer progression becomes crucial.
This is exactly the setting wherein the Prostate Active Lifestyle Study (PALS) trial arises: to answer if lifestyle interventions targeting weight loss affect obesity biomarkers related to changes in prostate cancer progression in men on AS. In their recently published study in the journal Cancer, Drs. Jonathan Wright, Marian Neuhouser and Jeannette Schenk showed that structured diet and exercise lead to significant weight loss and improve glucose-regulation biomarkers among overweight and obese men with prostate cancer on AS.
The PALS was a randomized clinical trial focusing on overweight and obese men choosing AS after their prostate cancer diagnosis. They were randomly assigned to one of two groups: the intervention group used a 6-month structured diet and exercise program in its pursuit of a 7% weight loss. This program included engaging in at least 150 minutes of moderate exercise per week, and adopting dietary changes aimed at reducing calorie intake by 500-1000 kcal/day. Meanwhile, the control group received basic dietary and physical activity guidelines without the structured regimen. The interventions were tailored based on the Diabetes Prevention Program, ensuring a personalized approach to the participants' needs, and the main goal was to observe changes in glucose regulation biomarkers, which are crucial for understanding cancer progression.
The study's outcomes were promising. Participants in the intervention group not only achieved significant weight loss but also showed notable improvements in key glucose regulation biomarkers. These results starkly contrasted with the control group, which saw minimal changes in these factors. Interestingly, there were no significant differences in prostate cancer pathology between the two groups, indicating that while lifestyle changes impact metabolic health, their direct effect on cancer progression within the study's timeframe remains inconclusive.
This study emphasizes the critical role of diet and exercise in managing the metabolic underpinnings of prostate cancer. The marked improvements in glucose regulation biomarkers in the intervention group highlight a promising avenue for slowing cancer progression through lifestyle modifications. Although the study did not conclusively link these changes to direct cancer outcomes, it lays the groundwork for future research. Numerous other studies have established a connection between these metabolic biomarkers and prostate cancer, emphasizing that changes in these biomarkers are significant in the context of cancer progression and outcomes. The alterations observed in glucose-regulation biomarkers underscore the critical importance of metabolic health management in potentially influencing prostate cancer prognosis and patient well-being. Moreover, the study advocates for the Diabetes Prevention Program's potential adaptability and effectiveness in a prostate cancer context, suggesting a viable, cost-effective strategy for enhancing the quality of life among men on AS.
The PALS study highlights the need for lifestyle medicine to complement traditional oncological approaches. This approach not only promises to enhance the quality of life for individuals living with cancer but also opens new avenues for personalized, lifestyle-focused strategies of cancer care, bringing hope and a new chapter for the millions of patients living with cancer.
Looking ahead, the team is focused on expanding their understanding of the mechanisms at play. When asked about the future direction of this research, Dr. Wright responded, “We need to delve deeper into how these lifestyle changes might influence prostate cancer. Our ongoing analyses of prostate biopsy tissues and body composition data from DXA scans will shed light on the tissue-level impacts of our intervention.” This insight emphasizes the research team's commitment to uncovering the nuanced effects of lifestyle interventions on prostate cancer, promising further advancements in this vital field of study.
Fred Hutch/University of Washington/Seattle Children’s Cancer Consortium Member Drs. Neuhouser, Wright, Lin, Gore, Etzioni, Plymate, and Gulati contributed to this study.
This study received support through grants from the Veterans Affairs Research Service and National Cancer Institute. Additional funding from the MXD Championships provided through institutional funds.
Wright, J. L., Schenk, J. M., Gulati, R., Beatty, S. J., VanDoren, M., Lin, D. W., Porter, M. P., Morrissey, C., Dash, A., Gore, J. L., Etzioni, R., Plymate, S. R., & Neuhouser, M. L. (2024). The Prostate Cancer Active Lifestyle Study (PALS): A randomized controlled trial of diet and exercise in overweight and obese men on active surveillance. Cancer, 10.1002/cncr.35241. Advance online publication.