ASPO Abstracts
Statin use and risks of colon cancer recurrence and second cancer events
Category: Survivorship & Health Outcomes/Comparative Effectiveness Research, Survivorship & Health Outcomes/Comparative Effectiveness Research
Conference Year: 2018
Abstract Body:
Purpose: To evaluate the association between statin use and colon cancer recurrence in a large, population-based study. Methods: We conducted a retrospective cohort study of adults with stage I-IIIa colon cancer diagnosed between 1995-2014 in Kaiser Permanente (KP) Colorado or KP Washington. All cases had surgical treatment and were cancer-free (based on imaging results) for at least 90 days after their final day of treatment (date of complete surgery, last chemotherapy, or last radiation therapy). Statin prescriptions were obtained from pharmacy dispensing and claims data; people were considered a user on the date of their first fill after cancer diagnosis and remained in this category through the end of follow-up. We abstracted information from medical records and tumor registries on colon cancer recurrences and second primary cancers at all anatomic sites. We followed subjects until death, health plan disenrollment, or through the date of chart abstraction. Using Cox proportional hazards models, we estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for 1) colon cancer recurrence, and 2) second cancer events (recurrences and second primaries at any anatomic site) comparing statin-users to non-users. HRs were adjusted for age, year of diagnosis, sex, study site, stage, race, smoking status, body mass index, Charlson comorbidity score, and statin use in the year before diagnosis. Results: Among 2,040 people with a mean age at diagnosis of 70 years, 937 (45.9%) used statins after diagnosis. Compared to non-users, a greater proportion of statin users were male (53%), ever smokers (59%), and had more comorbidities at diagnosis (29% with Charlson score >2). After a median follow-up of 4.9 years, 452 had a second cancer event, including 152 with a colon cancer recurrence. The crude recurrence rates were 10.4 (95%CI 7.7-13.7) per 1,000 person-years among statin users and 14.3 (95%CI 11.6-17.3) per 1,000 person-years among non-users. In multivariable models, statin use was not associated with recurrence (HR=1.05, 95%CI=0.63-1.75) but was associated with a reduced risk of any second cancer event (HR=0.65, 95%CI=0.51-0.83). Conclusions: Statin use may reduce the risk of second cancer events, but not by reducing the risk of colon cancer recurrence.
Keywords: colon cancer recurrence statins