Breast conservation for mammographically occult carcinoma

Preoperative mammography is an essential part of the evaluation of patient eligibility for breast conserving therapy.

It is uncertain whether factors that contribute to the nonvisualization of carcinoma on mammograms are indications for mastectomy. The purpose of this study was to determine if the failure to identify clinically evident carcinoma on a mammogram is a contraindication to breast conserving therapy.

An analysis of 268 women with 269 clinically evident carcinomas who were treated from June 1988 to September 1993 was performed. Contraindications to breast preservation included multicentric tumors, diffuse indeterminate microcalcifications, pregnancy, prior irradiation to the breast region, the inability to achieve negative margins after two surgical procedures, and a large tumor to breast ratio.

Mammographically occult tumors (MO) were present in 52 patients (19%). The mean age of patients with MO tumors was 52 versus 57 for mammographically evident (ME) tumors (p = 0.009), but the incidence by decade did not vary. Special histologic tumor types were more frequent among MO than ME tumors (13.5% vs. 1.8%, p < 0.001). Tumor size, the incidence of axillary node metastases, and stage did not vary. An equal proportion of patients with MO and ME tumors were candidates for breast preservation (67% vs. 70%), and a large tumor to breast ratio was the most common contraindication in both groups.

Even with modem mammographic technology, MO tumors remain a significant problem. This study did not demonstrate an association between MO tumors and factors such as size, unfavorable histology, or multicentricity which would preclude the use of breast conserving therapy. These results support the treatment of MO tumors with breast conserving surgery after a detailed clinical evaluation.