Aim: To determine whether preoperative factors, such as size of metastases in the sentinel lymph node (SLN), number of positive SLNs (1, >1), tumoral grade, lymphovascular invasion (LVI) and tumoral size can predict the presence of metastases in non-SLNs, when the SLN is positive.
Methods: The study population was 1 146 breast cancer patients. Lymphadenectomy was performed in 150. Three groups of patients were established depending on the size of the metastases in SLNs: group A: <2 mm; group B: 2 < or =GC < or =5 mm; group C: > 5 mm. Either the chi(2) test or Fisher's test was performed to compare categorical variables, and a multivariate conditional logistic regression model for data sets was performed to identify the deterministic factors of metastases presence.
Results: Ten percent of group A, 28% of group B and 52% of group C presented non-SLN metastases. Patients with >1 positive-SLN presented significantly more non-SLN metastases than those with only one positive-SLN; 56% of patients with LVI presented non-SLN metastases versus 26% of those without LVI. The tumoral grade and size did not seem to have any influence on the number of patients with non-SLN metastases. The number of positive-SLNs and size of metastases were statistically associated with the presence of metastases.
Conclusions: In this study population, the probability of finding non-SLN metastases was statistically related to the size of the SLN metastases and the number of positive-SLNs.