TUCSON, Ariz., March 22, 2017 (GLOBE NEWSWIRE) -- Since 1971, when the UK national registry for breast cancer was started, the incidence of breast cancer has continued to increase worldwide. Breast cancer screening, which started in the 1980s, increased detection but cannot account for the continuing increase in cases, write actuary Patrick Carroll and colleagues in the spring issue of the Journal of American Physicians and Surgeons. The lifetime risk of breast cancer for women is now around one in seven for malignant tumors and one in six if in-situ lesions are included, they write.
Certain risk factors, they note, including childlessness, are widely acknowledged, as are protective factors such as a young age at the birth of the first child, further full-term pregnancies, and longer breastfeeding.
But most health authorities have been unwilling to acknowledge the long-term risk of hormonal contraceptives, although it is similar to that of hormone-replacement therapy, which doctors are now reluctant to prescribe, Carroll et al. observe. Likewise, epidemiologists are not warning women of the additional risk of induced abortion, and British medical journals do not publish articles showing the link. Authors note that under the 1967 Abortion Act two physicians must approve an abortion, and if an abortion-breast cancer link were accepted, many more professional liability cases would likely be brought.
Using a linear regression model incorporating cohort rates of fertility and induced abortions, Carroll et al. were able to forecast future incidence of breast cancer accurately.
Hormonal and reproductive risk factors also help to explain the “social gradient,” the authors write. Women in higher socioeconomic groups have a higher incidence of breast cancer. Upper class and upwardly mobile women may be more likely to have nulliparous abortions, later childbirth, and fewer children, authors suggest.
Accurate forecasting of future case numbers is important in planning treatment facilities, the authors state.
The Journal of American Physicians and Surgeons is published by the Association of American Physicians and Surgeons (AAPS), a national organization representing physicians in all specialties since 1943.