Staging role of micrometastatic sentinel lymph nodes in breast cancer

AIM: Axillary dissection may be avoided in patients with breast cancer and negative sentinel lymph node (SL); not all metastatic SL patients show metastasis on the remaining axillary lymph nodes. The purpose of this study was to evaluate the possible presence of metastases in the remaining axillary lymphatic glands, the so called not-SL, in patients with SL either macro- or micrometastatic, and to try to locate a subgroup of patients in which metastases are present only in SL. METHODS: A retrospective study was conducted in 91 patients who from March 2000 to June 2003 underwent a biopsy of SL and dissection of the axillary cavity (23 patients with micrometastatic SL and 68 with macrometastatic SL). A multivariate analysis evaluated the statistic association with not-SL metastases of almost 22 prognostic factors. RESULTS: Of the 68 patients affected by macrometastatic SL, 32 (47%) showed metastases of the not-SL; of the 23 patients with micrometastatic SL, 7 (30%) showed metastases of the not-SL. In the last 2 years, among all those patients with micrometastatic SL, the probability of disease at the not-SL reached the null percentage. During year 2000, 3 (50%) patients out of 6 with micrometastatic SL showed metastases at the not-SL; during years 2002/2003 no patients out of 8 with micrometastatic SL showed metastases at the not-SL. A multivariate analysis showed only 2 factors significantly associated to the metastatic not-SL: age (cut off 60 years) OR 4.6, P 0.003 and histological examination of the SL OR 2.8, P 0.003. CONCLUSIONS: The average frequency of disease of not-SL in patients with either micro- or macrometastatic SL is not so different than values observed in literature. The predictive disease value of the remaining axillary lymphatic glands of the micrometastatic SL reached the null percentage in the last 2 years, therefore at seems to depend on the operators experience in SL biopsy technique. Among patients with metastatic SL (micro and macro), it was not possible to detect a subgroup in which not-SL are not metastatic with reasonable certainty. Nevertheless, a multivariate analysis showed the histological factor of the SL, to be significantly associated to not-SL metastases, as well as to the age-factor.