Longitudinal Associations Between Physical Activity And Survival By Cancer Treatments In Endometrial Cancer Survivors

PURPOSE: Different cancer treatment modalities may alter the association between physical activity (PA) and cancer outcomes. Here, we report the associations of prediagnosis and postdiagnosis PA with survival based on different treatment combinations from our Alberta Endometrial Cancer Cohort Study. METHODS: Women diagnosed with invasive endometrial cancer (N = 540) were asked to recall prediagnosis lifetime PA about 2-4 months after diagnosis, and postdiagnosis PA about 2-4 years after diagnosis, using the Lifetime Total Physical Activity Questionnaire. Vital status, second primary cancers, recurrences, and treatments were collected from medical charts. Multivariable Cox regression models were used for analyses after adjusting for demographic, medical, and health characteristics. RESULTS: After a median follow-up of 16.7 years, there were 206 disease-free survival (DFS) events (recurrences, second primary cancers, and deaths). In terms of treatment combinations, 61.7% received surgery only, and 35.9% received surgery plus an adjuvant therapy. There was a statistically significant interaction between treatment combination and meeting PA guidelines (≥150 PA minutes/week) during prediagnosis (p = 0.001). In subgroup analysis, participants in the surgery-only group who met the PA guidelines during prediagnosis had an 18% lower risk of a DFS event (HR = 0.82; CI: 0.53-1.27) whereas participants in the surgery-plus-adjuvant group who met the PA guidelines during prediagnosis had a 47% higher risk of a DFS event (HR = 1.47; CI: 0.92-2.35). Conversely, there was no statistically significant interaction between meeting the PA guidelines during postdiagnosis and treatment combination (p = 0.61). In subgroup analysis, participants in the surgery-only group who met the PA guidelines during postdiagnosis had a 44% lower risk of a DFS event (HR: 0.56; CI: 0.32-0.99) similar to participants in the surgery-plus-adjuvant group who met the PA guidelines during postdiagnosis who had a 37% lower risk of a DFS event (HR: 0.63; CI: 0.33-1.20). CONCLUSIONS: The association between prediagnosis PA and DFS in endometrial cancer survivors may be altered by subsequent treatments. Conversely, the association between postdiagnosis PA and DFS does not appear to be affected by previous treatments.