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Effect of drug class on association of beta-blocker with ovarian cancer survival
Background: There is evidence in breast, colorectal and prostate cancer that patients who use beta-blocker (BB) medication have better cancer outcomes. There is conflicting evidence of similar benefits in ovarian tumours. We investigated whether type of drug effected association between BB use and survival within Irish ovarian cancer patients.
Method: Women diagnosed with invasive ovarian cancer (ICD code: C56) between 2001-2011 were identified from the National Cancer Registry Ireland. Those with continuous eligibility for a (means-tested) medical card in the year immediately prior to diagnosis were identified and linked to pharmacy claim records. Any BB exposure (WHO ATC: C07) in the year prior to diagnosis was determined. Associations between exposure and ovarian cause-specific survival (OvCSS) and all other causes was estimated using Cox regression (until follow-up 31/12/2012) adjusted for age, smoking, marital status, diagnosis year, urban/rural residence, deprivation, stage, grade, and surgery at diagnosis. Adjusted hazard ratios (AHR) and 95% CI are presented. Class of medication was a pre-planned subgroup and patients were classified as having exposure to: selective, non-selective, neither (reference category) or both.
Results: Of 3097 invasive ovarian cancers diagnosed 2001-2011, 1823 (59%) had a medical card for at least one year prior to diagnosis. Of these, 432 (24%) had some BB exposure in that year. 78% of women in the cohort had died by 31/12/2012 (median follow-up 5.8 years). Pre-diagnostic use was not associated with improved OvCCS (AHR=1.08, 95%CI 0.93,1.23) or other-cause survival. Exposure to selective drugs (AHR=1.11, 95%CI 0.95,1.30) was not significantly different to that of non-selective drugs (AHR=0.88, 95%CI 0.56,1.38), drug class interaction p=0.55.
Conclusions: In this large study of beta-blocker use in ovarian cancer, we observed no modification of association by drug class on cancer-specific survival.