Pure tubular carcinoma of the breast and sentinel lymph node biopsy: a retrospective multi-institutional study of 234 cases.

Background: Pure Tubular Carcinoma (PTC) of the breast is a rare histological subtype of invasive breast cancer characterized by a low rate of lymph node involvement. Currently there is no consensus on less surgical axillary node staging according to this histological subtype.
Methods: We performed a retrospective multi-institutional study. Inclusion criteria were PTC, sentinel lymph node detection (SLND) and conservative breast surgery.
Results: From January 1999 to December 2006, 234 patients were included in the study from 9 institutions. The median pathological tumor size was 9.59 (1-22) mm. SLN were successfully detected in 98% (229/234) of patients. Among the 234 patients, a macrometastasis was found in 6 cases (2.5%), micrometastasis in 15 cases (6.4%), and isolated cells in 2 cases (0.8%). In the case of patients with SLND macrometastasis, half of them had macrometastasis in the complementary axillary lymphadenectomy, and none in the case of SLN only micrometastasis or isolated cells. Of the 122 patients with a pathological tumor size <10 mm, none had sentinel node macrometastasis. According to a multivariate analysis, pathological tumor size (>10 mm) was the only parameter significatively linked to the risk of lymph node involvement (p = 0.007).
Conclusion: In a large multi-institutional series with SLND, we have shown that the risk of axillary lymph node involvement in PTC is very low. In the case of PTC <10 mm, we suggest that surgical axillary evaluation, even with SLND, may not be warranted.
(Copyright © 2012 Elsevier Ltd. All rights reserved.)