THE USE OF MAMMOGRAPHY IN BREAST PRESERVATION IN LOCALLY ADVANCED BREAST-CANCER

Purpose: As the feasibility of breast preservation in locally advanced breast cancer is currently under evaluation, little information is av ailable correlating mammographic changes to chemotherapy with local ou tcome. To evaluate the role of mammography in selecting candidates wit h locally advanced breast cancer for conservative local therapy, we an alyzed mammographic changes in the breast to induction chemotherapy an d correlated the radiologic appearance with pathologic outcome. Method s and Materials: From 1985 through 1993, 91 patients with Stage III br east cancer were enrolled on a multimodality clinical trial using chem ohormonal therapy followed by local treatment and maintenance therapy. Induction therapy consisted of cyclophosphamide, doxorubicin, methotr exate, and 5-fluorouracil with hormonal synchronization using tamoxife n and conjugated estrogens. After nine cycles, surgical biopsies of th e breast were performed. Through 1988, clinical examination alone dire cted the site for postinduction biopsy; for patients treated after 198 8, mammography, in addition to physical examination, determined the bi opsy location. Local treatment was determined by biopsy result. Patien ts with a pathologic complete response received radiation only to the breast and regional nodes, while those with pathologically proven resi dual disease underwent mastectomy and postoperative radiotherapy. Nine additional cycles of maintenance chemotherapy were administered. Resu lts: Fifty-three of 91 patients (58%) obtained; clinical complete resp onse (CR) to induction chemotherapy. Twenty-eight of the 53 women with a clinical CR had both pre- and postinduction mammograms. Of these 28 women, 9 obtained a pathologic CR and 19 obtained a pathologic partia l response (PR). Fifty-five percent (5) of the pathologic complete res ponders had resolution of mammographic abnormalities on the postinduct ion mammogram. Sixty-eight percent (13) of the pathologic partial resp onders had abnormal mammographic findings. The positive predictive val ue for residual cancer using physical examination was 92%, while the n egative predictive value was only 36%. Among patients with a clinical complete response, the positive and negative predictive values for res idual cancer using postinduction mammography were 79% and 56%, respect ively. Limitations of mammography included uncertain significance of r esidual microcalcifications and residual masses on postinduction chemo therapy mammograms. Conclusions: Although mammography improved the acc uracy of noninvasive evaluation in patients with a clinical complete r esponse, pathologic assessment was still required to determine appropr iate local therapy. More sensitive imaging modalities or modifications of film-screen mammography may improve noninvasive detection of resid ual disease following induction chemotherapy.