The impact of tamoxifen on breast recurrence, cosmesis, complications, and survival in estrogen receptor-positive early-stage breast cancer.

PURPOSE

To evaluate the impact of tamoxifen on breast recurrence, cosmesis, complications, overall and cause-specific survival in women with Stage I-II breast cancer and estrogen receptor positive tumors undergoing conservative surgery and radiation.

METHODS AND MATERIALS

From 1982 to 1991, 491 women with estrogen receptor positive Stage I-II breast cancer underwent excisional biopsy, axillary dissection, and radiation. The median age of patient population was 60 years with 21% < 50 years of age. The median follow-up was 5.3 years (range 0.1 to 12.8). Sixty-nine percent had T1 tumors and 83% had histologically negative axillary nodes. Re-excision was performed in 49% and the final margin of resection was negative in 64%. One hundred fifty-four patients received tamoxifen and 337 patients received no adjuvant therapy. None of the patients received adjuvant chemotherapy.

RESULTS

There were no significant differences between the two groups for age, race, clinical tumor size, histology, the use of re-excision, or median total dose to the primary. Patients who received tamoxifen were more often axillary node positive (44% tamoxifen vs. 5% no tamoxifen), and, therefore, a greater percentage received treatment to the breast and regional nodes. The tamoxifen patients less often had unknown margins of resection (9% tamoxifen vs. 22% no tamoxifen). The 5-year actuarial breast recurrence rate was 4% for the tamoxifen patients compared to 7% for patients not receiving tamoxifen (p = 0.21). Tamoxifen resulted in a modest decrease in the 5-year actuarial risk of a breast recurrence in axillary node-negative patients, in those with unknown or close margins of resection, and in those who underwent a single excision. Axillary node-positive patients had a clinically significant decrease in the 5-year actuarial breast recurrence rate (21 vs. 4%; p = 0.08). The 5-year actuarial rate of distant metastasis was not significantly decreased by the addition of adjuvant tamoxifen in all patients or pathologic node-negative patients. Pathologically node-positive patients had a significant decrease in distant metastasis (35 vs. 11%; p = 0.02). There were no significant differences in cause-specific survival for patients receiving tamoxifen when compared to observation (95% no tamoxifen vs. 89% tamoxifen; p = 0.24). Similar findings were noted for pathologically node-negative patients. However, axillary node-positive patients receiving tamoxifen had an improvement in 5-year actuarial cause-specific survival (90% tamoxifen vs. 70% no tamoxifen; p = 0.10). Cosmesis (physician assessment) was good to excellent in 85% of the tamoxifen patients compared to 88% of the patients who did not receive tamoxifen.

CONCLUSION

The addition of tamoxifen to conservative surgery and radiation in women with Stage I-II breast cancer and estrogen receptor positive tumors resulted in a modest but not statistically significant decrease in the 5-year actuarial risk of a breast recurrence. Tamoxifen significantly decreased the 5-year actuarial risk of distant metastasis in axillary node-positive patients and there was a trend towards improvement in cause-specific survival that was not statistically significant. Tamoxifen did not decrease the 5-year actuarial rate of distant metastasis in axillary node negative, patients and in this group, there was no improvement in cause-specific survival. Tamoxifen did not have an adverse effect on cosmesis or complications.