Age‐specific differences in the relationship between oral contraceptive use and breast cancer

Abstract

Background. Nearly all studies have suggested that the use of oral contraceptives (OC) is not associated with the aggregate risk of breast cancer diagnosed in women aged 20–54 years. Because of age‐specific differences in the breast cancer–parity relationship and because of age‐specific differences in other breast cancer risk factors, the Centers for Disease Control reexamined data from the Cancer and Steroid Hormone Study (CASH) to assess whether OC use has different effects on the risk of breast cancer at different ages of diagnosis. Methods. This population‐based case–control study was designed to examine the relationship between the use of OC and the risk of breast, ovarian, and endometrial cancer. CASH was conducted in eight geographic areas in the United States during 1980–1982. All participants were interviewed at home with a pretested standardized questionnaire including a calendar of life events and a photograph book of all pills marketed in the United States. Results. We found that the relationship between the risk of breast cancer and OC use appeared to vary by the age at diagnosis. Among women aged 20–34 years at diagnosis or interview, those who had ever used OC had a slightly increased risk of breast cancer (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0–2.1) compared with women of the same ages who had never used OC. Among these women, there were no trends of increasing or decreasing risk with any measure of OC use. Among women aged 35–44 years, there was no association between OC use and breast cancer. Among women aged 45–54 years, those who used OC had a slightly decreased risk of breast cancer (OR, 0.9; 95% CI, 0.8–1.0). Among these women, risk estimates decreased significantly with increasing time since first and last use. Conclusions. Although the slightly increased risk estimates for the youngest women were compatible with findings by other investigators, the decreased risk estimates for the oldest women have not been described in as many studies. Available data provide no reasons to change prescribing practices or the use of OC that are related to the breast cancer risk.

The association between oral contraceptive use and lobular and ductal breast cancer in young women

“…Analyzing younger and older women together could mask heterogeneity of effects due to age, since previous age-specific analyses of the association between oral contraceptive use and breast cancer (regardless of histologic type) have observed variation by age. 17,21,[23][24][25] Romieu et al 18 reported that there was little difference in the effect of oral contraceptive use among different breast cancer histologies, but the authors did not report the effect estimates for the different histologies. Newcomer et al 26 reported ORs of 1.2 (95% CI 5 0.9-1.6) for the association between oral contraceptive ever use and invasive lobular cancer and 1.0 (95% CI 5 0.9-1.1) for the association between oral contraceptive ever use and invasive ductal cancer.…”

“…It has been consistently shown that oral contraceptive use is associated with an increased risk of breast cancer in young women, [12][13][14][15][16][17][18][19][20][21][22][23][24][25] but not older women. 21,[23][24][25] Recently, Newcomer et al 26 reported that current oral contraceptive use, recent use, and older age at first use are associated with an increased risk of invasive lobular breast cancer, but not invasive ductal breast cancer in a population of middleaged women, suggesting that oral contraceptives may have effects related to specific histologic subtypes.…”

“…21,[23][24][25] Recently, Newcomer et al 26 reported that current oral contraceptive use, recent use, and older age at first use are associated with an increased risk of invasive lobular breast cancer, but not invasive ductal breast cancer in a population of middleaged women, suggesting that oral contraceptives may have effects related to specific histologic subtypes. It is unknown whether the associations between oral contraceptive use and breast cancer differs by histologic subtype among younger women-the age group most likely to experience increased risk of breast cancer due to oral contraceptive use.…”

Correlation of Age at Oral Contraceptive Pill Start with Age at Breast Cancer Diagnosis

“…Some studies have shown a small risk increase for developing breast cancer in women using the OCP whilst other studies were unable to demonstrate a correlation (16)(17)(18)(19). Kahlenborn Women of higher socio-economic status are at higher risk for the development of breast cancer (23,24).…”

Oral contraceptive use at a young age and the risk of breast cancer: an Icelandic, population-based cohort study of the effect of birth year

“…In recent years, several studies have demonstrated an association between oral contraceptive use and breast cancer when focusing on women diagnosed under the age of 45 and/or on young users (Pike et al, 1981;Meierik et al, 1986;McPherson et al, 1987;Kay and Hannaford, 1988;Miller et al, 1989;Olsson et al, 1989; UK National Case-Control Study Group, 1989; WHO Collaborative Study of Neoplasia and Steroid Contraceptives, 1990;Weinstein et al, 1991;Wingo et al, 1991;Rookus and van Leeuwen, 1994;Brinton et al, Received 22 March 1996Revised 15 July 1996A Accepted 25 July 1996 Correspondence to: L Tryggvad6ttir 1995). This may indicate effects in young users because women diagnosed under the age of 45 in recent years tend to belong to the birth cohorts exposed at a young age.…”