Meta-analysis on the association between non-steroidal anti-inflammatory drug use and ovarian cancer

Abstract

Aim: Animal and in vitro studies suggest that the use of non-steroidal anti-inflammatory drugs (NSAIDs) may be associated with reduced risk for ovarian cancer. However, results from these studies have been inconsistent. The aim of our study was to review and summarize the evidence provided by longitudinal studies on the association between NSAID use and ovarian cancer risk.

Methods: A comprehensive literature search for articles published up to December 2011 was performed. Prior to performing a meta-analysis, the studies were evaluated for publication bias and heterogeneity. Relative risk (RR) or odds ratios (OR) were calculated.

Results: Seventeen reports (13 case-control studies, one clinical trial and three cohort studies), published between 1998 and 2011 were identified. There was no evidence of an association between aspirin use and ovarian cancer risk based on a random-effects model (RR = 0.91, 95% confidence interval (CI) 0.82, 1.01) or a fixed-effects model (RR = 0.94, 95% CI 0.87, 1.01). Similarly, we did not find strong evidence of an association between non-aspirin NSAID use and ovarian cancer using a random-effects model (RR = 0.89, 95% CI 0.74, 1.08) or a fixed-effects model (RR = 0.86, 95% CI 0.76, 0.98). Furthermore, our analysis did not show a strong association between frequency or duration of non-aspirin-NSAID use and ovarian cancer.

Conclusions: Our findings indicate that there is no strong evidence of an association between aspirin/NA-NSAID use and ovarian cancer. However, this subject deserves further investigation.

Figure 1

Selection process (SIR, standardized incidence ratio; RR, relative risk; OR, odds ratio)

Figure 2

(A) Funnel plots of the relative risk of developing ovarian cancer, with the standard error, for all studies included in the meta-analysis. Relative risks are displayed on a logarithmic scale. The x axis represents standard error of log RR, and the y axis represents log RR. For aspirin use: P= 0.592 for the Begg–Mazumdar test; P= 0.178 for the Egger test. (B) Funnel plots of the relative risk of developing ovarian cancer, with the standard error, for all studies included in the meta-analysis. Relative risks are displayed on a logarithmic scale. The x axis represents standard error of log RR, and the y axis represents log RR. For non-aspirin-NSAID use: P= 0.051 for the Begg–Mazumdar test, P= 0.125 for the Egger test

Figure 3

Analysis of studies, listed by first author and publication year that examined ovarian cancer and its association with aspirin use. The relative risk and 95% CI for each study are displayed on a logarithmic scale. Pooled estimates are from a random-effects model

Figure 4

Analysis of studies, listed by first author and publication year that examined ovarian cancer and its association with non-aspirin-NSAID use. The relative risk and 95% CI for each study are displayed on a logarithmic scale. Pooled estimates are from a random-effects model