Association between oral contraceptive use and pancreatic cancer risk: A systematic review and meta-analysis

Abstract

BACKGROUND Studies on the association of oral contraceptive (OC) use and pancreatic cancer showed inconsistent findings. AIM To evaluate the relationship between OC use and pancreatic cancer risk. METHODS A literature search for observational studies (case-control and cohort studies) was conducted up to December 2020. A meta-analysis was performed by calculating pooled relative risks (RRs) and 95% confidence intervals (CIs). Heterogeneity was assessed using Cochran’s chi-square test and I 2 statistic. Subgroup analyses were performed by study design, source of controls in case-control studies, number of cases of pancreatic cancers, study quality according to Newcastle-Ottawa Scale score, geographical region and menopausal status. All analyses were performed using Review Manager 5.3 (RevMan 5.3). RESULTS A total of 21 studies (10 case-control studies and 11 cohort studies) were finally included in the present meta-analysis, comprising 7700 cases of pancreatic cancer in total. A significant association was observed between the ever use of OC and pancreatic cancer risk in the overall analysis (RR = 0.85; 95%CI = 0.73-0.98; P = 0.03). Duration of OC use (< 1 year, < 5 years, 5-10 years, > 10 years) was not significantly associated with the risk of pancreatic cancer. Subgroup analyses revealed a statistically significant subgroup difference for the geographic region in which the study was conducted (Europe vs Americas vs Asia; P = 0.07). Subgroup analyses showed a statistically significant decrease in pancreatic cancer risk and OC use in high-quality studies, studies conducted in Europe, and in postmenopausal women. CONCLUSION Despite the suggested protective effects of OC use in this meta-analysis, further epidemiological studies are warranted to fully elucidate the association between the use of OC and pancreatic cancer risk.

Use of oral contraceptives and risk of pancreatic cancer in women: A recalculated meta-analysis of prospective cohort studies

“…Based on the results of the recalculated sRRs and DRMA, the OCU may not be associated with the risk of PCW. Because my conclusion contradicts that reported by Ilic et al [ 1 ], it is necessary to re-evaluate the direction and statistical significance of risk through an updated meta-analysis in the future.…”

“…I recently read the systematic review and meta-analysis conducted by Ilic et al [ 1 ] comprising 10 case-control studies and 11 cohort studies, which concluded that the use of oral contraceptives (OCU) was associated with a decreased risk of pancreatic cancer in women (PCW) [summary relative risk (sRR) = 0.85; 95% confidence intervals (CI) = 0.73-0.98; P = 0.03]. Interestingly, the subgroup analysis according to the study design showed no statistical significance in case-control studies but showed borderline statistical significance in cohort studies (sRR = 0.84; 95%CI = 0.70-1.00; P = 0.05).…”

“…However, while reviewing the results of the 11 selected cohort studies, I found the following potential errors. First, among the 11 selected studies, the study by Teras et al [ 2 ] was a cohort study that analyzed the mortality of PCW; therefore, excluding this study would be valid based on the research hypothesis; second, it would be necessary to include the two cohort studies[ 3 , 4 ] that were considered in other studies on the risk of various cancers associated with OCU[ 5 , 6 ]; finally, in the two studies that did not provide an RR for the ever group[ 7 , 8 ], the RR's direction was opposite to that of the forest plot shown in the study by Ilic et al [ 1 ].…”

Serum biomarker-based early detection of pancreatic ductal adenocarcinomas with ensemble learning

“…HRT has, in fact, been observed to reduce the risk of pancreatic cancer 73 . OCP use, on the other hand, might reduce risk in postmenopausal women but the results at this point are unclear 74 . Another drawback of the current study lies with the lack of or insufficient information on grading, staging, tumour size, and diabetes type, but cohorts with samples taken years before diagnosis are scarce.…”