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 s entinel node [SN] detection in multiple foci breast cancer. Seventy-nine pa tients with infiltrative breast carcinoma (diagnosed pre-operatively by cor e biopsy) and a mean age of 55 (31-78) years were enrolled. All patients we re free of previous homolateral surgery, chemotherapy, locoregional radioth erapy or prevalent axillary lymph node. Using for 0.1 ml injections of 1.8 MBq, the technetium - 99 m 100 nm filtered sulfur colloid was injected bu s ubareolar way (group I) in 16 cases of radiologically cancer with multiple invasive foci and 31 of radiologically unifocal cancer, and by peritumoral way (group II) in 32 cases of radiologically unifocal cancer. Scintigrams w ere obtained 2 to 4 hours after the injections and radioactive nodes were d etected preoperatively 18 hour after the injection by intraoperative detect ion probe. Individual removal of all radioactive nodes was followed by axil lary dissection at levels I and II of Berg including Rotter area control. A ll sentinel nodes were submitted to standard histopathological analysis on serial sections at 500 mu intervals completed by immunohistochemistry for c ytokeratin on negative SN. SN were detected by scintigrams in 85% and 88% o f 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 com posed of 69% ductal, 22% lobular and 9% tubular carcinomas, and group II of 87% ductal, 10% lobular and 3% tubular carcinomas. Seven and 5 radiologica lly unifocal tumors were in fact with multiple invasive foci at histology i n groups I and II respectively. The complete scintigraphic procedure permit ted 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 gro up II, the SN were metastatic in 9 patients (28%), 5 of them with the posit ivity restricted to the SN. No false negative result (SN negative and other axillary nodes positive) was observed ingroup I and only one false negativ e result in group II which was related to a cancer with histological multip le invasive foci. Sensitivities were 100% and 90%, and negative predictive values were 100% and 95%, for groups I and II respectively. Subareolar inje ction 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 peritumor al injection.