Background Numerous predictive factors for cutaneous melanoma metastases to sentinel lymph nodes have been identified; however, few have been found to be reproducibly significant. This study investigated the significance of factors for predicting regional nodal disease in cutaneous melanoma using a large multicenter database. Methods Seventeen institutions submitted retrospective and prospective data on 3463 patients undergoing sentinel lymph node (SLN) biopsy for primary melanoma. Multiple demographic and tumor factors were analyzed for correlation with a positive SLN. Univariate and multivariate statistical analyses were performed. Results Of 3445 analyzable patients, 561 (16.3%) had a positive SLN biopsy. In multivariate analysis of 1526 patients with complete records for 10 variables, increasing Breslow thickness, lymphovascular invasion, ulceration, younger age, the absence of regression, and tumor location on the trunk were statistically significant predictors of a positive SLN. Conclusions These results confirm the predictive significance of the well-established variables of Breslow thickness, ulceration, age, and location, as well as consistently reported but less well-established variables such as lymphovascular invasion. In addition, the presence of regression was associated with a lower likelihood of a positive SLN. Consideration of multiple tumor parameters should influence the decision for SLN biopsy and the estimation of nodal metastatic disease risk.

The presence of tumor at the lateral margin of punch biopsies is an expected result, since this method is often used to diagnose lesions with a large diameter. The presence of positive deep margins in 22% of shave biopsy specimens compromises the ability of this technique to properly stage patients.

The timing of sentinel node biopsy in the setting of neo-adjuvant chemotherapy for breast cancer is controversial. Sentinel node biopsy performed after neo-adjuvant chemotherapy may save patients with a nodal response the morbidity of an axillary lymph node dissection. A retrospective review of prospectively collected data compared sentinel node biopsies performed after patients had received neo-adjuvant chemotherapy with patients who had not received neo-adjuvant chemotherapy. Demographic factors, tumor characteristics, and the results of the sentinel node biopsies and completion lymph node dissections (when applicable) were compared. A total of 231 axillary procedures (224 patients) were evaluated. The patients who received neo-adjuvant chemotherapy (NEO; N=52) were younger, had higher grade tumors, were more likely to have a mastectomy, and were more likely to have ER-negative and HER-2/neu positive tumors than the patients who did not receive neo-adjuvant chemotherapy (NON; N=179). The mean clinical tumor size in the neo-adjuvant group was 4.5cm (±1.8) prior to chemotherapy; the post-chemotherapy pathologic size was 1.4cm (±1.3). A sentinel node was identified in all cases. There were no significant differences between the groups in the mean number of sentinel nodes removed (NEO=3.3; NON=3.1; p=0.545), the percentage of positive axillae (NEO=24%; NON=21%; p=0.776) or the mean number of positive sentinel nodes (NEO=1.3; NON=1.5; p=0.627). There was no difference in the percentage of completion lymph node dissections with additional positive nodes (NEO=20%; NON=35%; p=0.462); there was a difference in the number of nodes removed in the completion lymph node dissections (mean NEO=12.0; NON=16.4; p=0.047). Sentinel node biopsy performed after neo-adjuvant chemotherapy appears to be an oncologically sound procedure and may save some patients the morbidity of a complete lymph node dissection.

There are no significant differences in the principal results of SLN biopsy between PO and IO injection methods. Dermal radiocolloid injection after induction of anesthesia seems to be an oncologically sound procedure and may be a preferable technique.