Role of Oral Contraceptive (OC) as a risk factor for cervical cancer remained controversial and unclear.
Objective
To evaluate risk of cervical cancer in OC users and non-users through a comprehensive systematic review.
Search Strategy
Literature search conducted in databases from January 1990 till August 2019 using various search terms.
Selection Criteria
Primary research studies that evaluated and assessed the association of OC use with cervical cancer with study design of case control or cohort types published in English language.
Data Collection and Analysis
PRISMA guided review was done by two independent researchers. Effect size estimated by pooled Odds ratio with 95 % Confidence Interval (CI) in random effect models on OC pill use for the risk of cervical cancer.
Results
Review included 19 studies. Overall risk of invasive cancer on OC use was found to be significant with unknown status of HPV OR (95 % CI) as 1.51 (1.35, 1.68) and for unknown HPV as 1.66 (1.24, 2.21). Adenocarcinoma, squamous cell carcinoma and carcinoma in situ had significant association with OR (95 % CI) of 1.77 (1.4, 2.24), 1.29 (1.18, 1.42) and 1.7 (1.18, 2.44) respectively.
Conclusion
OC pills use had a definite associated risk for developing cervical cancer specially for Adenocarcinoma and longer duration of OC pills use.
oral contraceptive cervical cancer risk meta-analysis, OC pill use cervical adenocarcinoma risk, hormonal contraception HPV cervical cancer association, oral contraceptive duration cervical cancer systematic review, combined oral contraceptives squamous cell carcinoma cervix, contraceptive pill carcinoma in situ cervix risk, oral contraceptive cancer risk pooled odds ratio, hormonal contraception long-term cervical cancer risk, OC use HPV status cervical cancer epidemiology, oral contraceptive adverse effects cervical neoplasia
PMID 32114321 32114321 DOI 10.1016/j.ejogrb.2020.02.014 10.1016/j.ejogrb.2020.02.014 Asthana et al. 2020, Asthana 2020
Cite this article
Asthana, S., Busa, V., & Labani, S. (2020). Oral contraceptives use and risk of cervical cancer-A systematic review & meta-analysis. European journal of obstetrics, gynecology, and reproductive biology, 247, 163-175. https://doi.org/10.1016/j.ejogrb.2020.02.014
Asthana S, Busa V, Labani S. Oral contraceptives use and risk of cervical cancer-A systematic review & meta-analysis. Eur J Obstet Gynecol Reprod Biol. 2020;247:163-175. doi:10.1016/j.ejogrb.2020.02.014
Asthana, Smita, et al. "Oral contraceptives use and risk of cervical cancer-A systematic review & meta-analysis." European journal of obstetrics, gynecology, and reproductive biology, vol. 247, 2020, pp. 163-175.
In addition to HPV, high parity and hormonal contraceptives have been associated with cervical cancer (CC). However, most of the evidence comes from retrospective case-control studies. The aim of this study is to prospectively evaluate associations between hormonal factors and risk of developing cervical intraepithelial neoplasia grade 3 (CIN3)/carcinoma in situ (CIS) and invasive cervical cancer (ICC). Methods and findingsWe followed a cohort of 308,036 women recruited in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study. At enrollment, participants completed a questionnaire and provided serum. After a 9-year median follow-up, 261 ICC and 804 CIN3/CIS cases were reported. In a nested case-control study, the sera from 609 cases and 1,218 matched controls were tested for L1 antibodies against HPV types 11,16,18,31,33,35,45,52,58, and antibodies against Chlamydia trachomatis and Human herpesvirus 2. Multivariate analyses were performed to estimate hazard ratios (HR), odds ratios (OR) and corresponding 95% confidence intervals (CI). The cohort analysis showed that number of full-term pregnancies was positively associated with CIN3/CIS risk (p-trend = 0.03). Duration of oral contraceptives use was associated with a significantly increased risk of both CIN3/CIS and ICC (HR = 1.6 and HR = 1.8 respectively for ≥ 15 years versus never use). Ever use of menopausal hormone therapy was associated with a reduced risk of ICC (HR = 0.5, 95%CI: 0.4-0.8). A non-significant reduced risk of ICC with ever use of intrauterine devices (IUD) was found in the nested case-control analysis (OR = 0.6). Analyses restricted to all cases and HPV seropositive controls yielded similar results, revealing a significant inverse association with IUD for combined CIN3/CIS and ICC (OR = 0.7). Even though HPV is the necessary cause of CC, our results suggest that several hormonal factors are risk factors for cervical carcinogenesis. Adherence to current cervical cancer screening guidelines should minimize the increased risk of CC associated with these hormonal risk factors.
To demonstrate the application of causal inference methods to observational data in the obstetrics and gynecology field, particularly causal modeling and semi-parametric estimation. Human immunodeficiency virus (HIV)-positive women are at increased risk for cervical cancer and its treatable precursors. Determining whether potential risk factors such as hormonal contraception are true causes is critical for informing public health strategies as longevity increases among HIV-positive women in developing countries. We developed a causal model of the factors related to combined oral contraceptive (COC) use and cervical intraepithelial neoplasia 2 or greater (CIN2+) and modified the model to fit the observed data, drawn from women in a cervical cancer screening program at HIV clinics in Kenya. Assumptions required for substantiation of a causal relationship were assessed. We estimated the population-level association using semi-parametric g-computation, inverse probability of treatment weighting, and targeted maximum likelihood estimation. We identified 2 plausible causal paths from COC use to CIN2+: via HPV infection and via increased disease progression. Study data enabled estimation of the latter only with strong assumptions of no unmeasured confounding. Of 2,519 women under 50 screened per protocol, 219 (8.7%) were diagnosed with CIN2+. Marginal modeling suggested a 2.9% (95% confidence interval 0.1%, 6.9%) increase in prevalence of CIN2+ if all women under 50 were exposed to COC; the significance of this association was sensitive to method of estimation and exposure misclassification. Use of causal modeling enabled clear representation of the causal relationship of interest and the assumptions required to estimate that relationship from the observed data. Semi-parametric estimation methods provided flexibility and reduced reliance on correct model form. Although selected results suggest an increased prevalence of CIN2+ associated with COC, evidence is insufficient to conclude causality. Priority areas for future studies to better satisfy causal criteria are identified.
The International Agency for Research on Cancer (IARC) Monographs on the carcinogenic risk to humans concluded that combined oral oestrogen–progestogen contraceptives are carcinogenic to humans (IARC, 2007). This evaluation was made on the basis of increased risks for cancer of the breast (among current and recent users only), cervix and liver (in populations that are at low risk for hepatitis B viral infection). There is also convincing evidence in humans that these agents confer a protective effect against cancer of the endometrium and ovary.
To assess the risk of oral contraceptives on the occurrence of cervical cancer. Material and A hospital-based case-control study was conducted. Sixty women patients with histologically confirmed invasive cervical cancer and 180 healthy women as the control group who attended the King Chulalongkorn Memorial Hospital, Bangkok, Thailand were recruited. Information about the use of oral contraceptives and other cervical cancer risk factors were obtained from personal interviews. The risk factors were evaluated by using odds ratio (OR). 60 women with invasive cervical cancer and 180 healthy controls were interviewed by the investigators. Compared with non-users, patients who had ever used or currently used oral contraceptive had an increased risk of cervical cancer (OR 1.45; 95% CI 0.79-2.64). However the risk was not statistically significant. Considering the duration of use, patients who had used oral contraceptives for 3 years or less did not have an increased risk of cervical cancer (OR 0.78; 95% CI 0.39-1.77). Nevertheless, the odds ratio of oral contraceptive pill use for more than 3 years was 2.57 (95% CI 1.22-5.49) which was statistically significant. Long-term use of oral contraceptive might be a cofactor that increases the risk of cervical carcinoma. Further investigations should be conducted to confirm this risk. However, Pap smear has to be done routinely in long-term oral pill users.