Long‐term association of physical activity with survival by primary cancer treatment in endometrial cancer: The Alberta Endometrial Cancer Cohort Study

Adjuvant therapies are provided to endometrial cancer patients with advanced risk and may impact the associations of lifestyle with survival. We examined the long-term associations of physical activity (PA) with survival outcomes in endometrial cancer survivors by primary cancer treatment. Women with endometrial cancer who underwent hysterectomy (N = 527) in Alberta, Canada between 2002 and 2006 recalled their lifetime pre-diagnosis PA shortly after diagnosis and their PA since diagnosis at 3.4 years follow-up using the Lifetime Total PA Questionnaire. Vital status was obtained through record linkage from Alberta Health Services, while recurrences and second primary cancers were abstracted from medical records. Cox proportional hazards models were used to examine interactions between PA and primary treatment (surgery alone vs. surgery plus adjuvant therapy) for overall survival (OS) and disease-free survival (DFS). Of 527 survivors, 333 underwent surgery alone and 194 underwent surgery plus adjuvant therapy. Over 16.7 years, 128 deaths and 194 DFS events occurred. For DFS, meeting PA guidelines pre-diagnosis (interaction p = .035) was associated with lower events in surgery alone but with higher events in surgery plus adjuvant therapy. Although other interactions between treatment regimen and PA were not statistically significant, overall, increasing PA showed lower risks of OS and DFS events in the surgery alone group, but showed higher risks in the surgery plus adjuvant therapy group. Associations between PA and survival may differ by primary treatment, with generally protective associations in the surgery alone group and harmful associations in the surgery plus adjuvant therapy.