Therapie und Prognose des kleinen Mammakarzinoms

Abstract

A retrospective clinical study included 1283 patients with breast cancer. 307 of 762 tumours with known diameter (mm) were classified as stage pT1 (TNM, 70). Four groups were formed to compare the prognosis in subgroups of pT1 cancers: 0-5 mm (n = 22), 6-9 mm (n = 22), 10 mm (n = 53) and 11-20 mm (n = 210). A comparison of three types of surgery was made: Radical subcutaneous mastectomy (12), bilateral modified subcutaneous mastectomy (10, 11), and modified radical mastectomy (Auchincloss, 3). Both forms of subcutaneous mastectomy were combined with adjuvant postoperative radiotherapy to the side of the tumour. In this trial, patients were younger at diagnosis than usually stated in the literature. Small breast cancers had the same localisation and histology as large ones. Axillary lymph node metastases were identified from a tumour diameter of 6 mm upwards. Bilateral tumours were seen in 2 of 22 patients with tumours less than or equal to 5 mm. Multifocal growth was observed also in the same size range. Histologically different simultaneous invasive unilateral cancers were seen starting at a diameter of 8 mm of the larger tumour. Systemic metastases were observed in tumours of 10 mm in diameter. Local recurrences occurred in breast cancers with a diameter of 2 mm and more. There were no recurrences in the area of the nipple or areola in pT1 cancers. Small breast cancers did not appear to be biologically different from larger lesions. No prognostic subgroups of pT1 were evident beyond the established TNM staging. Disease-free survival was not significantly different between the three surgical approaches. Local recurrence was significantly less frequent after breast-conserving surgery. A negative influence of local recurrence on the prognosis was observed to a similar extent irrespective of the type of surgery. The concept of "minimal breast cancer" suggesting ablative surgery for a heterogeneous group of preinvasive and small invasive lesions is outdated. The different forms of subcutaneous mastectomy are a therapeutic alternative in the context of breast-conserving surgery of small infiltrating breast cancers. Especially the modified subcutaneous mastectomy (Beller) combines a good cosmetic result without prognostic impairment and with a potential reduction of the risc of contralateral breast cancer. Further potential applications include prophylactic treatment of high-risk patients with preinvasive lesions.