[Subareolar injection of 99m-Tc sulfur colloid for sentinel nodes identification in multifocal invasive breast cancer].

The objective were to study the relevance of the subareolar injection for sentinel node [SN] detection in multiple foci breast cancer. Seventy-nine patients with infiltrative breast carcinoma (diagnosed pre-operatively by core biopsy) and a mean age of 55 (31-78) years were enrolled. All patients were free of previous homolateral surgery, chemotherapy, locoregional radiotherapy or prevalent axillary lymph node. Using four 0.1 ml injections of 1.8 MBq, the technetium-99m 100 nm filtered sulfur colloid was injected by subareolar way (group I) in 16 cases of radiologically cancer with multiple invasive foci and 31 cases of radiologically unifocal cancer, and by peritumoral way (group II) in 32 cases of radiologically unifocal cancer. Scintigrams were obtained 2 to 4 hours after the injections and radioactive nodes were detected peroperatively 18 hours after the injection by intraoperative detection probe. Individual removal of all radioactive nodes was followed by axillary dissection at levels I and II of Berg including Rotter area control. All sentinel nodes were submitted to standard histopathological analysis on serial sections at 500 mu intervals completed by immunohistochemistry for cytokeratin on negative SN. SN were detected by scintigrams in 85% and 88% of the cases of group I and group II respectively, but in 98% and 97% of the cases of respectively both groups by intraoperative probe. Group I was composed of 69% ductal, 22% lobular and 9% tubular carcinomas, and group II of 87% ductal, 10% lobular and 3% tubular carcinomas. Seven and 5 radiologically unifocal tumors were in fact with multiple invasive foci at histology in groups I and II respectively. The complete scintigraphic procedure permitted the detection of a mean number of 2.7 (1-7) SN in group I and 2.3 (1-4) in group II (NS). In group I, the SN were metastatic in 22 patients (48%), 15 of them with the metastases being restricted to the SN, whereas in group II, the SN were metastatic in 9 patients (28%), 5 of them with the positivity restricted to the SN. No false negative result (SN negative and other axillary nodes positive) was observed in group I and only one false negative result in group II which was related to a cancer with histological multiple invasive foci. Sensitivities were 100% and 90%, and negative predictive values were 100% and 95%, for groups I and II respectively. Subareolar injection of radiocolloid allows identification of SN in cases of unifocal and multiple cancer. The mean number of SN detected by the subareolar method is not significantly different, although higher, to that detected by peritumoral injection.