Pre- and post-diagnostic meat intake in relation to risk of recurrence and mortality among individuals with stage I-III colorectal cancer.

Abstract

Processed meat and unprocessed red meat intakes are associated with increased colorectal cancer (CRC) risk, but evidence on associations with mortality after a CRC diagnosis is inconsistent. To date, no studies examined associations between unprocessed poultry intake and mortality, or assessed cancer recurrence risk as a separate outcome measure. We included data from 2484 individuals, who were newly diagnosed with stage I-III CRC, participating in 2 prospective cohort studies. Dietary intake was assessed at diagnosis and 6 months after diagnosis. Multivariable Cox proportional hazards regression models and restricted cubic splines were used to examine associations between pre- and post-diagnostic meat intake and risk of recurrence and all-cause mortality. We performed subgroup analyses by sex, disease stage and primary tumour location. During a median follow-up time of 5.0 years for recurrence analyses and 6.4 years for mortality analyses, 336 recurrences and 409 deaths occurred. Pre- and post-diagnostic processed meat and unprocessed red meat intakes were not associated with risk of recurrence nor all-cause mortality. At both timepoints, a higher unprocessed poultry intake was non-linearly associated with a decreased mortality risk, with the lowest risk observed at 20 g/day (hazard ratio: 0.63, 95% confidence interval: 0.47-0.85), compared to 0 g/day. Results were not substantially different by sex, disease stage and primary tumour location. To conclude, a higher pre- and post-diagnostic intake of unprocessed poultry, but not processed meat and unprocessed red meat, was associated with a decreased all-cause mortality risk in individuals with stage I-III CRC. Future studies in independent study populations should confirm these findings.