Abstract 2220: Associations between post-diagnostic lifestyle and dietary patterns with prostate cancer survival in the Multiethnic Cohort
Authors: Wang Anqi , Van Blarigan Erin L. , Cheng Iona , Chan June M. , Wan Peggy , Park Song-Yi , Chen Fei , Marchand Loic Le , Wilkens Lynne , Kenfield Stacey A. , Haiman Christopher A. 
Published: March 2024

Abstract
Background: Prostate cancer (PCa) remains a leading cause of cancer-related death among men despite high 5-year survival rates for localized and regional diseases. This study evaluated healthy lifestyle and dietary patterns in relation to PCa survival in a multiethnic population.
Methods: We prospectively followed 2,603 men with non-metastatic PCa in the Multiethnic Cohort (MEC) for a median duration of 10.9 years (497 African American, 754 Japanese American, 577 Latino, 129 Native Hawaiian, and 646 White men) starting in 1993. We documented 1,321 deaths, including 196 from PCa. Lifestyle pattern was assessed after diagnosis by a previously reported PCa Behavior Score, which includes BMI, physical activity, and smoking, and a modified version including diet (based on the sum of saturated fat, whole milk, alcohol, and processed meat intake). We also evaluated six indices of inflammatory and insulinemic potential of diet and lifestyle patterns (E-DII, EDIP, EDIH, ELIH, EDIR, and ELIR); and three indices of plant-based diets: an overall plant-based diet index (PDI), a healthful PDI (hPDI), and an unhealthful PDI (uPDI). We used Cox proportional hazards models to calculate hazard ratios (HR) and 95% confidence intervals (CI) for the relationship between each index with PCa-specific and all-cause mortality. We adjusted for education, race/ethnicity, smoking, BMI, physical activity (if not part of the score), family history of PCa, and first course of treatment.
Results: Across the five racial/ethnic groups, Japanese American men exhibited healthier lifestyle and dietary patterns post-diagnosis, while African American and Native Hawaiian men tended to have less healthy behaviors. The PCa Behavior Score was statistically significantly associated with a reduced risk of all-cause mortality (HR per point=0.71, 95% CI 0.63-0.80), and a similar trend persisted when incorporating diet into the score. The PDI was statistically significantly inversely associated with all-cause mortality (HR per SD=0.90, 95% CI 0.83-0.97), while the uPDI showed a positive association (HR=1.10, 95% CI 1.12-1.18). None of the lifestyle or dietary patterns were associated with PCa mortality (p-values&gt;0.05). No clear trends were observed for inflammatory and insulinemic dietary patterns after PCa diagnosis with all-cause or PCa-specific mortality.
Conclusion: Adopting a healthy lifestyle and diet was associated with longer overall survival among men with PCa. We did not find these practices to be associated with a lower risk of PCa-specific mortality among men diagnosed with non-metastatic disease. However, 85% of the observed deaths during follow-up were due to other causes; this underscores the importance of counseling all men, including those with non-metastatic prostate cancer on health behaviors to manage comorbidities.
Citation Format: Anqi Wang, Erin L. Van Blarigan, Iona Cheng, June M. Chan, Peggy Wan, Song-Yi Park, Fei Chen, Loic Le Marchand, Lynne Wilkens, Stacey A. Kenfield, Christopher A. Haiman. Associations between post-diagnostic lifestyle and dietary patterns with prostate cancer survival in the Multiethnic Cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2220.