Purpose: Research suggests patients are motivated to supplement standard cancer care with healthy lifestyle changes. However, few studies have prospectively investigated whether these changes result in positive outcomes. In this study, our objective was to examine the associations between vitamin D supplementation and quality of life (QoL), cancer recurrence, and all-cause mortality in stage II CRC patients following diagnosis.
Methods: A total of 453 newly diagnosed patients were enrolled from the North Carolina Central Cancer Registry. Data on demographic variables, treatment, and health behaviors were collected by interview at diagnosis, 12, and 24 months post-diagnosis. QoL was measured using the FACT-C and SF-12 questionnaires.
Results: After adjustment for potential confounders, the survivors who used vitamin D supplements had a better CCS score (subscale of FACT-C) over 24 months compared to non-users (β = 1.28; 95 % CI 0.07-2.48). This association persisted among calcium users (β = 2.41; 95 % CI 1.01-3.82), but not in non-users (β = 0.34; 95 % CI -1.45-2.13) (P interaction = 0.09). No association was observed with risk of recurrence or mortality.
Conclusions: This suggests that vitamin D supplementation may jointly influence QoL with calcium following diagnosis in CRC survivors. These results also support the notion that clinicians should recommend positive lifestyle changes in conjunction with the standard of care.
Keywords: Colorectal cancer; Mortality; Quality of life; Recurrence; Vitamin D.