BREAST-TUMOR RESPONSE TO PRIMARY CHEMOTHERAPY PREDICTS LOCAL AND DISTANT CONTROL AS WELL AS SURVIVAL

The purpose of the present paper was to evaluate correlations between clinical response to chemotherapy and outcome in a subgroup analysis o f premenopausal patients with tumours considered too large for breast conserving surgery, treated with primary chemotherapy (n = 200) from a previously published trial (Scholl S.M., Fourquet A., Asselain B, et al. Eur J Cancer 1994, 30A, 645-652). Objective response rates amounte d to 65% following four courses. In a multivariate Cox regression anal ysis, comparing seven parameters, the following variables were associa ted with poor survival: clinically involved nodes [Nib: RR: 2.7 (95% C I 1.3-5.3)], the failure to respond to chemotherapy [D: RR: 2.62 (95% CI 1.3-5)] and a raised S phase fraction [SPF > 5%: RR: 2.4 (95% CI 1. 25)]. Parameters associated with increased metastatic recurrence rates , by order of entry in the model, were: young age [<35: RR: 2.46 (95% CI 1.2-5)], large clinical tumour size [T3: RR: 2.02 (95% CI 1.23.4)], poor histological grade (SBR III: RR: 1.93 (95% CI 1.1-3.3)] and the failure to respond to chemotherapy [D: RR: 1.91 (95% CI 1-3.4)]. The a ssessment of both tumour cell proliferation rates as well as possibly drug resistance markers (although not available in the present study) should be helpful in selecting patients likely to benefit from intensi fied chemotherapy regimens. The most accurate predictor of response in the present study appeared to be the response to chemotherapy treatme nt itself.