Abstract
An analysis of the occurrence of breast cancer in this long-term prospective cohort study shows a significant relative risk (RR) in women who have ever used oral contraceptives (OC) of 3.33 in women age 30 to 34 years at diagnosis and an RR of 5.88 (P = 0.0011) in women who were parity 1 at the time of diagnosis. In women below the age of 35 years the RR of 2.38 was not significant. There was no increased risk in women over the age of 35 years. A significant trend relating to duration of use was demonstrable in women who were parity 1 in the analysis of both current and ever-users. An analysis by time since stopping OC use revealed a significant trend in all ever-users, but the trends were much steeper in women of parity 1 or aged 30 to 34 years at diagnosis. There was no evidence that the increased rates in OC users were related to the oestrogen or progestogen dose. The 5 year survival rate in users diagnosed under the age of 35 years was significantly poorer than in comparable non-users. It is possible that the increased rates in younger OC users might be due to an accelerated presentation of breast cancer in those women who would otherwise have been diagnosed at a later time. The non-significant excess risk in users under 35 years of age was approximately 1 in 7,000 users per year. The unresolved discrepancies between the results of the published studies make it impossible at the present time to decide whether or not OC use is associated with an increased risk of breast cancer.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Harris N. V., Weiss N. S., Francis A. M., Polissar L. Breast cancer in relation to patterns of oral contraceptive use. Am J Epidemiol. 1982 Oct;116(4):643–651. doi: 10.1093/oxfordjournals.aje.a113447. [DOI] [PubMed] [Google Scholar]
- MacMahon B., Cole P., Lin T. M., Lowe C. R., Mirra A. P., Ravnihar B., Salber E. J., Valaoras V. G., Yuasa S. Age at first birth and breast cancer risk. Bull World Health Organ. 1970;43(2):209–221. [PMC free article] [PubMed] [Google Scholar]
- McPherson K., Vessey M. P., Neil A., Doll R., Jones L., Roberts M. Early oral contraceptive use and breast cancer: results of another case-control study. Br J Cancer. 1987 Nov;56(5):653–660. doi: 10.1038/bjc.1987.261. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meirik O., Lund E., Adami H. O., Bergström R., Christoffersen T., Bergsjö P. Oral contraceptive use and breast cancer in young women. A joint national case-control study in Sweden and Norway. Lancet. 1986 Sep 20;2(8508):650–654. doi: 10.1016/s0140-6736(86)90166-2. [DOI] [PubMed] [Google Scholar]
- Miettinen O. Estimability and estimation in case-referent studies. Am J Epidemiol. 1976 Feb;103(2):226–235. doi: 10.1093/oxfordjournals.aje.a112220. [DOI] [PubMed] [Google Scholar]
- Miller D. R., Rosenberg L., Kaufman D. W., Schottenfeld D., Stolley P. D., Shapiro S. Breast cancer risk in relation to early oral contraceptive use. Obstet Gynecol. 1986 Dec;68(6):863–868. [PubMed] [Google Scholar]
- Olsson H., Olsson M. L., Möller T. R., Ranstam J., Holm P. Oral contraceptive use and breast cancer in young women in Sweden. Lancet. 1985 Mar 30;1(8431):748–749. doi: 10.1016/s0140-6736(85)91280-2. [DOI] [PubMed] [Google Scholar]
- Paul C., Skegg D. C., Spears G. F., Kaldor J. M. Oral contraceptives and breast cancer: a national study. Br Med J (Clin Res Ed) 1986 Sep 20;293(6549):723–726. doi: 10.1136/bmj.293.6549.723. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pike M. C., Henderson B. E., Casagrande J. T., Rosario I., Gray G. E. Oral contraceptive use and early abortion as risk factors for breast cancer in young women. Br J Cancer. 1981 Jan;43(1):72–76. doi: 10.1038/bjc.1981.10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pike M. C., Henderson B. E., Krailo M. D., Duke A., Roy S. Breast cancer in young women and use of oral contraceptives: possible modifying effect of formulation and age at use. Lancet. 1983 Oct 22;2(8356):926–930. doi: 10.1016/s0140-6736(83)90450-6. [DOI] [PubMed] [Google Scholar]
- Rosenberg L., Miller D. R., Kaufman D. W., Helmrich S. P., Stolley P. D., Schottenfeld D., Shapiro S. Breast cancer and oral contraceptive use. Am J Epidemiol. 1984 Feb;119(2):167–176. doi: 10.1093/oxfordjournals.aje.a113735. [DOI] [PubMed] [Google Scholar]