PREOPERATIVE HISTOLOGICAL DIAGNOSIS OF BREAST-CANCER

Background: A concordant triple assessment (clinical, mammographic and cytological) diagnosis of breast malignancy allows for pre-operative planning of surgery and may also allow for one-stage surgery. However, while the accuracy of cytology is high, it is unable to distinguish i nvasive cancer from ductal carcinoma in situ (DCIS). A malignant mass may be due to pure in situ cancer and hence axillary dissection may be avoided if pre-operative histology is available. Methods: A consecuti ve series of 300 cases of breast cancer treated over the last 5 years by the two authors was analysed to determine: the method of achieving pre-definitive operation histology; the number of stages of surgery re quired; and the number of cases of mass-forming DCIS which could be su sceptible to over-treatment. Results: Of 289 patients undergoing local definitive surgery for breast cancer, 12 (42%) had clinical masses pr edominantly due to DCIS and in most of these patients axillary dissect ion was avoided. Histology was obtained prior to definitive surgery in 272 (94.1%) patients, by intra-operative frozen section in 159 (55.0% ), incisional biopsy in 37 (12.8%), needle localization biopsy in 62 ( 21.5%) and core biopsy in 14 (4.8%). A total of 189 patients (65.4%) u nderwent one-stage surgery only. Breast conservation was achieved in 2 10 (72.7%) patients. Those requiring mastectomy were significantly mor e likely to have required two stages of surgery as were those with les ions detected by screening. Conclusions: Mass-forming DCIS cannot be p redicted pre-operatively by triple assessment alone; and therefore pre -operative histology is required to avoid axillary dissection. Pre-ope rative histology may be obtained by core biopsy or intra-operative fro zen section to identify DCIS and distinguish it from invasive disease, but both allow a one-stage surgical procedure in the majority of case s.