Early start of adjuvant chemotherapy may improve treatment outcome for premenopausal breast cancer patients with tumors not expressing estrogen receptors. The International Breast Cancer Study Group

Systemic therapy

Our knowledge base on systemic therapy for breast cancer continues to expand, including further information regarding hormonal prevention in high-risk women, beneficial effects of tamoxifen in noninvasive disease, an update on primary systemic therapy, and optimization of adjuvant strategies, including data on adjuvant chemoendocrine regimens. The proper evaluation of high-dose strategies has been jeopardized by a serious episode of scientific misconduct. New data are also available on palliative options, bisphosphonates, antibody therapies, and novel targets. Data continue to evolve on the role and optimal schedules of taxanes in early-stage and advanced breast cancer. These and other important recent findings are discussed in this review article.

Response to primary chemotherapy in breast cancer patients with tumors not expressing estrogen and progesterone receptors

BACKGROUND

We recently demonstrated that in premenopausal patients with estrogen receptors (ER)-absent tumors, early initiation of systemic chemotherapy after primary surgery might improve outcome. These data indicate a different responsiveness to chemotherapy for tumors not expressing hormone receptors. To test this hypothesis we evaluated the responsiveness to preoperative chemotherapy in patients with ER and progesterone receptors (PgR)-absent tumors.

PATIENTS AND METHODS

Patients with biopsy-proven T2-T3, N0-2 breast cancer treated at a single institution from January 1995 to August 1999 with preoperative chemotherapy were retrospectively evaluated. ER and PgR were determined immunohistochemically and classified for this purpose as absent (0% of the cells positive) or positive (> or = 1% of the cells).

RESULTS

On 117 evaluable patients 72 had an objective response (61%). A significant difference in response was observed for patients with ER and PgR absent compared with those with ER and/or PgR-positive tumors (82% vs. 57%, P = 0.03 Fishers's exact test). Pathological complete remission rates were also significantly different in the two groups (23% vs. 7%, respectively; P = 0.04).

CONCLUSIONS

The different degree of response according to hormone receptors expression supports the hypothesis that tumors not expressing both ER and PgR might represent a different clinical entity in terms of chemotherapy responsiveness.