A potential association was recognized between oral contraceptive (OC) use by younger women for long durations and possible protection for colorectal cancer, according to an article published online in the journal Cancer Epidemiology, Biomarkers & Prevention.
The researchers analyzed and categorized OC use every 2 years from 1976 to 2010 using data of 88,691 participants in the Nurses’ Health Study I (NHSI) and of 93,080 participants in the Nurses’ Health Study II (NHSII).
The categories that were established included ever use, duration of use, and time since last use. All incident colorectal cancer cases from NHSI and NHSII through 2010 were included in the analysis (age at diagnosis = 36–88, N = 1,764 and age at diagnosis = 33–64, N = 206, respectively).
Results showed ever OC use was not related to colorectal cancer incidence in NHSI nor in NHSII [1.01 (0.91, 1.12) and 1.03 (0.69, 1.53), respectively.]
The longer duration (5+ years) OC use cohort in NHSII was inversely associated with the risk of colon cancers (Ptrend = 0.02) compared to never-users—although endpoints were limited.
Little evidence was found to support an association between OC use and protection against colorectal cancer; however, the potential association between longer duration OC use by younger women warrants further study.
Background: It remains unclear if oral contraceptive (OC) use is associated with the incidence of colorectal cancer. Few studies have examined this association by duration of OC use, time since last OC use, and different cancer subsites.