abstract: Chinese Journal of Cancer Research - Attributable causes of breast cancer and ovarian cancer in China: Reproductive factors, oral contraceptives and hormone replacement therapy

Abstract

Objective

To provide an evidence-based, consistent assessment of the burden of breast cancer attributable to reproductive factors (RFs, including nulliparity, mean number of children, age at first birth and breastfeeding), use of oral contraceptives (OCs, restricted to the age group of 15–49 years), and hormone replacement therapy (HRT), as well as of the burden of ovarian cancer attributable to the mean number of children in China in 2005.

Methods

We derived the prevalence of these risk factors and the relative risk of breast and ovarian cancer from national surveys or large-scale studies conducted in China. In the case of RFs, we compared the exposure distributions in 2001 and counterfactual exposure.

Results

Exposure of RFs in 2001 was found to account for 6.74% of breast cancer, corresponding to 9,617 cases and 2,769 deaths, and for 2.78% of ovarian cancer (711 cases, 294 deaths). The decrease in mean number of children alone was responsible for 1.47% of breast cancer and 2.78% of ovarian cancer. The prevalence of OC use was 1.74% and the population attributable fraction (PAF) of breast cancer was 0.71%, corresponding to 310 cases and 90 deaths. The PAF of breast cancer due to HRT was 0.31%, resulting in 297 cases and 85 deaths.

Conclusion

RFs changes in China contributed to a sizable fraction of breast and ovarian cancer incidence and mortality, whereas HRT and OCs accounted for relatively low incidence of breast cancer in China.

abstract: Oral Contraceptives and the Risk of Venous Thromboembolism: An Update

Risk factors for carcinoma of the fallopian tube in women with and without a germline BRCA mutation

Reminder on stats: < 1.0 is decreased risk; > 1.0 is increased risk; OR=overall risk; edited some stats for ease of reading - see abstract/read more:

Conclusions

Parity and oral contraceptive use are associated with reduced risks of fallopian tube cancer. In contrast, hormone replacement therapy may be associated with an increase in the risk of fallopian tube cancer.

Oral contraceptive use and breast or ovarian cancer risk in BRCA1/2 carriers: A meta-analysis

CONCLUSIONS: OC users carrying an ascertained BRCA1/2 mutation have a reduced risk of ovarian cancer, proportional to the duration of use. There is no evidence that recent OC formulations increase breast cancer risk in carriers

abstract: Hormone prevention strategies for breast, endometrial and ovarian cancers

"The prevention of epithelial ovarian cancer (EOC) is of particular interest given its high mortality rate and the lack of a cost-effective screening program. OC (oral contraceptives) usage significantly diminishes the incidence of EOC, in both the general population, as well as in patients with BRCA 1 or 2 mutations. Risk reduction is greatest with prolonged usage and persists for more than 30 years after OC use, but diminishes over time. Prospective, randomized trials, designed to control for all known variables, are mandatory to fully assess the potential for hormonal chemoprevention in breast, endometrial and ovarian cancers."