[Critical study of our initial experience of 993 sentinel node biopsies for breast surgery]

Identification of sentinel node (SN) involvement predictive factors, non-sentinel node involvement predictive factors, selective prognosis of each group of patients by study of breast surgery cases with sentinel node sampling.

Prospective monocentric registering of 993 sentinel node samples routinely taken between January 2001 and October 2005, covering technical aspects of detection (colorimetric and radio-isotope), pathological results (serial sections 5 Mmicro thick prior to staining hematoxylin-eosine-saffron and if necessary, by immune histochemistry cytokeratine high molecular weight), therapeutics and follow-up (average period: 32 months (3-69).

Seven hundred and sixteen patients (72.1%) were free of sentinel node involvement. Among positive sentinel node patients (27.9%), 14.5% presented macrometastasis, 11% micrometastasis and 2.4% isolated tumor cells (CTI). Sentinel node involvement risk factors included: related to clinical features, age (2 years younger in the micrometastatic group compared to the macrometastatic group); related to tumor caracteristics, size (12.15 mm for the negative SN group, 15.4 mm for the micrometastatic group and 16.25 mm for the macrometastatic group), grading (a majority of grade I encountered with micrometastasis versus macrometastasis) and multifocality (macrometastasis SN associated with multilocular tumor in 77.8% cases, micro metastasis SN in 22.2% cases and negative SN in 6.7% cases). Predictive factors do not differ for micro- or macrometastasic involvement. Among features concerning secondary axillary dissection, 47.1% (66/140) were positive with a macrometastatic SN, 12.1% (13/107) with micrometastic SN. Predictive factors of positive secondary axillary dissection were tumor size, grading, micrometastasis size and micrometastasis multifocality. With a 32 months mean follow-up, the positive micrometastasis sub-group (with or without positive secondary axillary dissection) expressed one only metastatic recurrence (0.9%); on the contrary, three patients (2.1%) issued from the macrometastatic SN group, expressed metastatic recurrence. One only local axillary recurrence (0.14%) occurred among negative SN (717 cases); no axillary recurrence occurred among the 30 patients without secondary axillary dissection (CTI [22 cases], micrometastatic SN group [5 cases] and macrometastatc group [3 cases]).

First, 72.1% of T0 or T1 tumors, avoid adverse axillary dissection effects. Second, micrometastatic involvement predictive factors do not differ from macrometastatic ones and those of positive secondary axillary dissection among micrometastatic SN do not appear clearly : the risk of axillary recurrence is low: at the very most, it seems possible to propose a safe guideline, avoiding secondary axillary dissection only for selected group of lower risk patients: tumoral size < 10 mm, grade I, monocentric SN involvement. Third, it is not possible to differentiate a selective prognosis between negative, CTI, micrometastatic and macrometastatic SN subgroups probably because of a short follow-up. Fourth, teaching through companionship is fully valided by the secondary minimal rate of axillary recurrence.