Women with a mutation in BRCA1 or BRCA2 face a lifetime risk of breast cancer of approximately 80 %. Tamoxifen treatment of the first cancer has been associated with a reduction in the risk of a ...subsequent contralateral cancer. We studied 1,504 women with a known BRCA1 or BRCA2 mutation, 411 women with bilateral breast cancer (cases) and 1,093 women with unilateral breast cancer (controls) in a matched case–control study. Control women were of similar age and had a similar age of diagnosis of first breast cancer as the cases. For each woman who used tamoxifen, the starting and stopping dates were abstracted and the duration of tamoxifen use was calculated. Three hundred and thirty-one women had used tamoxifen (22 %); of these 84 (25 %) had completed four or more years of tamoxifen, the remainder stopped prematurely or were current users. For women with up to 1 year of tamoxifen use, the odds ratio for contralateral breast cancer was 0.37 (95 % CI 0.20–0.69;
p
= 0.001) compared to women with no tamoxifen use. Among women with 1–4 years of tamoxifen use the odds ratio was 0.53 (95 % CI 0.32–0.87;
p
= 0.01). Among women with four or more years of tamoxifen use the odds ratio was 0.83 (95 % CI 0.44–1.55;
p
= 0.55). Short-term use of tamoxifen for chemoprevention in BRCA1 and BRCA2 mutation carriers may be as effective as a conventional 5-year course of treatment.
To estimate the 15-year survival following a diagnosis of stage I breast cancer among women who carry a BRCA1 mutation and to determine predictors of mortality, including the use of chemotherapy. ...Patients were 379 women with stage I breast cancer for whom a BRCA1 mutation had been identified, in herself or in a close family member. Patients were followed for up to 15 years from the initial diagnosis of breast cancer. Survival rates were estimated for women by age, tumor size (≤1 cm; >1 cm), ER status (±), and by chemotherapy (yes/no). 42 women died of breast cancer in the follow-up period (11.2 %). Survival rates were similar for women with cancers of size 0–1.0 cm and size 1.1–2.0 cm. Of the 267 women in the study who used chemotherapy, 21 had died (7.9 %) compared to 21 deaths among 112 women who did not receive chemotherapy (18.8 %;
p
= 0.002). The 15-year survival was 89.4 % for women who received chemotherapy and was 73.1 % for women who did not receive chemotherapy (
p
= 0.08; log rank). The adjusted hazard ratio for death following a diagnosis of stage I breast cancer associated with chemotherapy was 0.53 (95 % CI 0.28–1.07;
p
value 0.06) after adjusting for age of diagnosis, tumor size, and estrogen receptor status. This was statistically significant only among women with ER-negative breast cancers (HR = 0.28; 95 % CI 0.10–0.79;
p
= 0.02). BRCA1 positive women who are treated for stage I breast cancer with chemotherapy have better survival than those who do not receive chemotherapy. The difference cannot be explained by other prognostic factors. All women with invasive breast cancer and a BRCA1 mutation should be considered to be candidates for chemotherapy.
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