Future possibilities in the prevention of breast cancer: Breast cancer prevention trials

The available results from breast cancer chemoprevention trials are reviewed. Four trials using tamoxifen have been performed, of which three have reported efficacy results. A fifth trial using raloxifene has also been reported. The largest tamoxifen trial showed approximately 50% reduction in breast cancer incidence in the short term, but the two smaller trials did not find any reduction. Greater agreement exists for side effects; incidences of thromboembolic disease and endometrial cancers are raised approximately threefold when tamoxifen is used for 5 years. The possible reasons for the discrepancy in breast cancer reduction are explored. A review of trial parameters does not clearly explain this difference, and a meta-analysis indicates that all results are compatible with a 40% reduction in short-term incidence. Several important questions remain regarding the clinical implications of this result, including the effect on mortality, the appropriate risk groups for chemoprevention and the long-term effects on incidence. Continued follow up of these trials is crucial for resolving these issues

Immunohistochemical Phenotype of Breast Cancer during 25-Year Follow-up of the Royal Marsden Tamoxifen Prevention Trial.

The randomized, double-blinded Royal Marsden Tamoxifen Breast Cancer Prevention Trial in healthy high-risk women started in 1986 and is still blinded. Eligible participants (n = 2,471) were randomly assigned to tamoxifen (20 mg/d) or placebo for 8 years. Analysis in 2006 showed a 30% risk reduction of estrogen receptor (ER)-positive invasive breast cancer mostly in the posttreatment period. Biomarker analysis in this population may identify any subgroup-specific preventive effects tamoxifen. After a median follow-up of 18.4 years, 242 patients had developed invasive cancer, 134 on placebo and 108 on tamoxifen. From these, 180 tissue blocks were available and ER, progesterone receptor (PgR), Ki67, HER2, and EGFR were immunohistochemically analyzed. A 32% reduction in ER+ and PgR+ invasive cancers resulted after 8 years of treatment. Quantitative levels of ER and PgR were lower in the tamoxifen-treated group, significantly so for ER (P = 0.001). These lower ER levels were restricted to the posttreatment period (P = 0.018). Among the ER+ group, there was a similar proportional decrease in PgR+ and PgR- tumors by tamoxifen. The median levels of Ki67 were similar in both arms. The numbers of HER2-positive and EGFR-positive cancers were higher in the tamoxifen arm but not significantly so. In conclusion, the preventive effects of tamoxifen result in reduced ER-positive but not ER-negative tumors and reduced ER expression in the ER-positive cases largely confined to the posttreatment period. Overall reductions in PgR expression are explained by lower frequency of ER-positive cases. Impact on Ki67, HER2, and EGFR was modest. Cancer Prev Res; 10(3); 171-6. ©2017 AACR

8th International Conference: Primary Therapy of Early Breast Cancer, St Gallen, Switzerland, March 12–15 2003

The International St Gallen Breast Cancer Conference concentrates almost exclusively on adjuvant, multimodal primary therapy for early breast cancer. Begun 25 years ago, this meeting was initially held every 4 years, but therapeutic progress, new strategies and provocative trials data have accelerated to the extent that conferences are now held biennially. The meeting this year was attended by almost 3000 delegates. Major topics included new prognostic and predictive markers in early breast cancer, the best use of adjuvant chemotherapy and endocrine therapy, and innovations in local surgery and radiation therapy

A high incidence of vertebral fracture in women with breast cancer

Because treatment for breast cancer may adversely affect skeletal metabolism, we investigated vertebral fracture risk in women with non-metastatic breast cancer. The prevalence of vertebral fracture was similar in women at the time of first diagnosis to that in an age-matched sample of the general population. The incidence of vertebral fracture, however, was nearly five times greater than normal in women from the time of first diagnosis [odds ratio (OR), 4.7; 95% confidence interval (95% CI), 2.3–9.9], and 20-fold higher in women with soft-tissue metastases without evidence of skeletal metastases (OR, 22.7; 95% CI, 9.1–57.1). We conclude that vertebral fracture risk is markedly increased in women with breast cancer. © 1999 Cancer Research Campaig

Relationship of ZNF423 and CTSO with breast cancer risk in two randomised tamoxifen prevention trials

This work was supported by the National Cancer Institute at the National Institute of Health (Grant number prime award: 5U19CA148065-03Rev; sub-award: 114080_5029147 to JC) and Cancer Research UK (Grant number C569/A16891). MD received funding from the Royal Marsden NIHR Biomedical Research Centre. This work was also supported by the Da Costa Foundation for Breast Cancer Prevention

Bone loss and the aromatase inhibitors

The increasing use of systemic adjuvant therapies has considerably improved the prognosis from early breast cancer. However, some of these therapies affect bone metabolism, resulting in osteoporosis. Aromatase inhibitors lower circulating oestrogen levels to almost unrecordable levels in postmenopausal women, predisposing them to bone loss with an increase in fracture risk. Ongoing clinical trials are favouring the use of the aromatase inhibitors over tamoxifen and this may advocate greater use of these drugs in the future. Strategies for the identification and management of treatment-induced bone loss are currently being defined

The role of bisphosphonates in breast cancer: The present and future role of bisphosphonates in the management of patients with breast cancer

At least 25% of patients with breast cancer develop skeletal metastases, with bone the site of disease producing the greatest morbidity. It is apparent that the bisphosphonates present an important component of the treatment strategy. They are now the treatment of choice in tumour-induced hypercalcaemia, and they can reduce bone pain and skeletal complications such as pathological fractures. In addition, bisphosphonates are being increasingly evaluated in the prevention of bone metastases and to prevent and treat cancer therapy-induced osteoporosis. Ongoing research is aimed at trying to define the optimum route, dose, schedule and type of bisphosphonate

Economic evaluation of chemoprevention of breast cancer with tamoxifen and raloxifene among high-risk women in Japan

Raloxifene was approved for chemoprevention against breast cancer among high-risk women in addition to tamoxifen by the US Food and Drug Administration. This study aims to evaluate cost-effectiveness of these agents under Japan's health system. A cost-effectiveness analysis with Markov model consisting of eight health states such as healthy, invasive breast cancer, and endometrial cancer is carried out. The model incorporated the findings of National Surgical Adjuvant Breast and Bowel Project P-1 and P-2 trial, and key costs obtained from health insurance claim reviews. Favourable results, that is cost saving or cost-effective, are found by both tamoxifen and raloxifene for the introduction of chemoprevention among extremely high-risk women such as having a history of atypical hyperplasia, a history of lobular carcinoma in situ or a 5-year predicted breast cancer risk of ⩾5.01% starting at younger age, whereas unfavourable results, that is ‘cost more and gain less' or cost-ineffective, are found for women with a 5-year predicted breast cancer risk of ⩽5.00%. Therapeutic policy switch from tamoxifen to raloxifene among postmenopausal women are implied cost-effective. Findings suggest that introduction of chemoprevention targeting extremely high-risk women in Japan can be justifiable as an efficient use of finite health-care resources, possibly contributing to cost containment