New lumps in the breast following conservation treatment for early breast cancer.

A new lump in the breast following conservation treatment for early breast cancer may represent a recurrence of the disease or may be a benign lesion. Clinical evaluation of these lumps is often extremely difficult and, potentially, mammography would seem to be of great importance in the assessment. Between November 1981 and March 1986, 214 patients with operable breast cancers of 4 cm or less in diameter underwent conservative treatment. The conservation technique comprised synchronous excision of the primary tumour without a wide margin, axillary clearance, interstitial irradiation with iridium 192 (2000 cGy), and subsequent external beam radiotherapy to the breast (4600 cGy). After an average follow-up of 26 months, 17 patients developed a new lump in the treated breast necessitating further biopsy. Seven of these were malignant and 10 benign. In the latter category the most frequent finding was fat necrosis. Clinically, the lesions were indistinguishable from each other. The mammographic signs, which best predicted malignancy, were either of a mass or of a malignant type of microcalcification. This study illustrates the problems associated with deciding the nature of a new lump in the breast following conservation treatment. Mammography is complementary to physical examination, and a base-line mammogram six months after completion of therapy is helpful. Despite the use of mammography, biopsy is the only definitive way of excluding recurrence.