Abstract
Epidemiological studies have shown that early first pregnancy reduces the risk of developing breast cancer, which indicates that initiation of the disease occurs at an early age. Thus the subclinical lesion of breast cancer might already be present in the breast before childbearing begins and the growth of any such focus might be modified by the endocrine changes of pregnancy. To test this hypothesis the relation between parity and age at presentation was studied in 341 unselected patients with breast cancer presenting to a single clinic. The mean age at presentation was 5.2 years lower in parous than nulliparous women (p < 0.001) and fell with increasing parity. It is concluded that reproductive history influences not only the risk of breast cancer but also the latent interval of a proportion of breast carcinomas.
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- DAO T. L., SUNDERLAND H. Mammary carcinogenesis by 3-methylcholanthrene. I. Hormonal aspects in tumor induction and growth. J Natl Cancer Inst. 1959 Sep;23:567–585. [PubMed] [Google Scholar]
- MCCORMICK G. M., MOON R. C. EFFECT OF PREGNANCY AND LACTATION ON GROWTH OF MAMMARY TUMOURS INDUCED BY 7,12-DIMETHLBENZ(A) ANTHRACENE (DMBA). Br J Cancer. 1965 Mar;19:160–166. doi: 10.1038/bjc.1965.19. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MacMahon B., Cole P., Brown J. Etiology of human breast cancer: a review. J Natl Cancer Inst. 1973 Jan;50(1):21–42. doi: 10.1093/jnci/50.1.21. [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]
- Moon R. C. Relationship between previous reproductive history and chemically induced mammary cancer in rats. Int J Cancer. 1969 May 15;4(3):312–317. doi: 10.1002/ijc.2910040308. [DOI] [PubMed] [Google Scholar]
- Tokunaga M., Norman J. E., Jr, Asano M., Tokuoka S., Ezaki H., Nishimori I., Tsuji Y. Malignant breast tumors among atomic bomb survivors, Hiroshima and Nagasaki, 1950-74. J Natl Cancer Inst. 1979 Jun;62(6):1347–1359. [PubMed] [Google Scholar]