ABSTRACT
The relationship between cervical cancer and the use of depot-medroxyprogesterone acetate (DMPA) was examined in a nationwide case-control study in Costa Rica. Cases were women ages 25-58 years of age with invasive squamous cell cancer (N = 149) or carcinoma in situ (CIS, N = 415) reported by the National Tumor Registry during 1982-84. Controls (N = 764) were randomly selected during a nationwide household survey. Using logistic regression, we adjusted for known risk factors for cervical cancer. DMPA use was associated with a risk of CIS of 1.1 (95% confidence interval 0.6-1.8) and a risk of invasive cancer of 1.4 (95% confidence interval 0.6-3.1). The slightly elevated risks observed may be the result of chance or a detection bias. One limitation of this study is that few women had used DMPA for longer than two years.
PIP: A nationwide case-control study was conducted in Costa Rica in 1984-85 to examine the association between depot-medroxyprogesterone acetate (DMPA) and cervical cancer. Cases, restricted to women 25-58 years of age at the time of diagnosis, were women with invasive squamous cell cancer (n = 149) or carcinoma in situ (CIS, n=415) reported by the National Tumor Registry during 1982-84. The 764 controls were randomly selected during a nationwide household survey. On average, the CIS cases were younger than controls; the invasive cases were older than controls. Both case groups were more likely than controls to be of low socioeconomic status, to have become sexually active at a young age, to report a history of a sexually transmitted disease or pelvic inflammatory disease, and to report having 3 or more partners in their lifetime. Ever users of DMPA had a risk of CIS of 1.1 when compared with never users. Women who 1st used DMPA before age 30 had a CIS risk of 0.6 whereas users who began use after age 39 had a risk of 2.0. Both of these risk estimates were based on small numbers of users. Ever users of DMPA had a risk of invasive cancer of 1.4 when compared with never users, but all estimates for invasive cancer were based on only 10 cases who reported use of DMPA. Few of the women had used DMPA for longer than 2 years.
Subject(s)
Carcinoma in Situ/chemically induced , Carcinoma, Squamous Cell/chemically induced , Contraceptive Agents, Female/adverse effects , Medroxyprogesterone/analogs & derivatives , Uterine Cervical Neoplasms/chemically induced , Adult , Carcinoma in Situ/epidemiology , Carcinoma, Squamous Cell/epidemiology , Costa Rica , Female , Humans , Medroxyprogesterone/adverse effects , Medroxyprogesterone Acetate , Middle Aged , Regression Analysis , Risk Factors , Uterine Cervical Neoplasms/epidemiologyABSTRACT
To examine the relationship between cervical cancer and oral contraceptive (OC) use, we analyzed data from a population-based, case-control study in Costa Rica. Women aged 25 to 58 years in whom cervical cancer was diagnosed and reported to the National Tumor Registry were examined as two separate case groups: invasive cervical cancer and carcinoma in situ (CIS). Controls were women aged 25 to 58 years identified through a national survey. Women who had used OCs had no increased risk of invasive cervical cancer compared with women who had never used OCs (relative risk, 0.8; 95% confidence interval, 0.5 to 1.3). Women who had used OCs had an increased risk of CIS compared with those who had never used OCs (relative risk, 1.6; 95% confidence interval, 1.2 to 2.2). However, further analyses indicated that this increased risk was confined to those who had recently used OCs. Also, the risk of CIS was not elevated in subgroups in which a history of cervical smears was not strongly linked to OC use. The elevated risk of CIS among OC users may therefore reflect a bias caused by enhanced detection of disease rather than a causal association.
Subject(s)
Contraceptives, Oral/adverse effects , Uterine Cervical Neoplasms/chemically induced , Adult , Carcinoma in Situ/epidemiology , Carcinoma, Squamous Cell/epidemiology , Costa Rica , Epidemiologic Methods , Female , Humans , Middle Aged , Registries , Risk Factors , Time Factors , Uterine Cervical Neoplasms/epidemiology , Vaginal SmearsABSTRACT
By 1981, 11% of married women in Costa Rica ages 20-49 years had used depot-medroxyprogesterone acetate (DMPA) and 58% had used oral contraceptives (OCs). Since 1977, the Costa Rican Ministry of Health has maintained a nationwide cancer registry. These circumstances provided an opportunity for a population-based, case-control study of DMPA, OCs, and breast cancer in Costa Rica. Cases were 171 women ages 25-58 years with breast cancer diagnosed between 1982 and 1984; controls were 826 women randomly chosen during a nationwide household survey. Cases and controls were interviewed with the use of a standard questionnaire covering their reproductive and contraceptive histories. Logistic regression methods were used to adjust for confounding factors. While few cases or controls had ever used DMPA, DMPA users had an elevated relative risk (RR) estimate of breast cancer of 2.6 (95% confidence limits = 1.4-4.7) compared with never users. However, no dose-response relationship was found; even the group of women who had used DMPA for less than 1 year had an elevated RR estimate (RR = 2.3; 95% confidence limits = 1.0-5.1). In contrast, OC users had no elevation in RR compared with never users (RR = 1.2; 95% confidence limits = 0.8-1.8). The results of the DMPA analysis are inconclusive. Before decisions are made on whether to continue providing this effective contraceptive method, other ongoing studies will need to confirm of refute these findings.
PIP: Depot-medroxyprogesterone acetate (DMPA) is used by approximately 2 million women world-wide. In Costa Rica, by 1981 11% of the married women had used DMPA. Although no definitive link between the use of DMPA and the development of cancer has been found, the possibility has been recognized as one of the reasons for the U.S food and Drug Administration denying approval of the drug. Since 1977, the Ministry of Health in Costa Rica has sustained a national cancer registry. The accuracy of the reporting of the registry was studied by comparing a sampling of gynecologic cancer cases in the year 1983 to the national registry. In examination of the records, an elevated relative risk of breast cancer for DMPA users was found (2.6), and an elevated relative risk for women who had even used DMPA for a short period of time (2.3). The failure to interview 1/3 of the cases, differences in detection and the misclassification of DMPA use contributed cumulatively to the belief that a positive connection between breast cancer and DMPA use could otherwise be drawn. In contrast to the association found between DMPA ever use and breast cancer, no connection was found between OC use and the incidence of breast cancer. However, due to the small number of DMPA users recorded and the void of complete and accurate recorded information, the study results remain inconclusive.