Feasibility of Sentinel Lymph Node Biopsy in Multiple Unilateral Synchronous Breast Cancer: Results of a French Prospective Multi-institutional Study (IGASSU 0502)

Background: To prospectively determine the feasibility of sentinel lymph node biopsy (SLNB) in preoperatively diagnosed multiple unilateral synchronous invasive breast cancers.

Patients And Methods: The Interest of Axillary Sentinel Lymph Node Biopsy in Multiple Invasive Breast Cancer (IGASSU) study was a prospective multi-institutional study with initial breast surgery, SLNB, and systematic axillary lymph node dissection (ALND). Patients eligible for the IGASSU study had an operable invasive multiple synchronous tumor (MST), defined as two or more physically separate invasive tumors in the same or different quadrant.

Results: From 1 March 2006 to 31 August 2007, 216 patients were prospectively included from 16 institutions. Of these patients, 211 were assessable. The SLNB-identified rate was 93.4% (197 of 211). The false-negative rate (FNR) was 13.6% (14 of 103) [95% confidence interval (CI) 7% to 20%], and the accuracy was 92.9% (183 of 197) (95% CI 89% to 96%). In a univariate analysis, tumor location (only external location versus other location) was the only clinicopathological factor influencing the FNR [22% (11%-33%) versus 7% (4%-10%)], even then median aggregate histological tumor size was smaller in external tumors [17 mm (range 12-80 mm) versus 34 mm (range 8-90 mm), P = 0.016].

Conclusion: With a FNR of 13.6%, we do not recommend SLNB as a routine procedure for MST, even for small tumor.