Pelvic sentinel lymph node biopsy in melanoma patients: is it worthwhile?

Routine retrieval of pelvic sentinel lymph nodes for melanoma rarely adds prognostic information or alters management

Pelvic sentinel lymph nodes (SLNs) are commonly identified during inguinal SLN biopsy for melanoma, but retrieval is not uniform among surgeons/centers. Few studies have assessed rates of micrometastases in pelvic versus superficial inguinal SLNs. Previous studies suggested that presence of pelvic SLNs was predicted by aggressive pathologic features and that their presence portended a worse prognosis. The objectives of this study were to examine presurgical predictors of pelvic SLNs among patients undergoing inguinal SLN biopsy, assess rates of micrometastases in superficial inguinal versus pelvic SLNs, and determine whether presence of pelvic SLNs was associated with long-term outcomes. Multivariable regression was used to assess presurgical factors associated with presence of pelvic SLNs. Rates of micrometastases in superficial inguinal versus pelvic SLNs in patients who had a pelvic SLN were compared with McNemar's test. Groin recurrence, disease-free survival (DFS), and disease-specific survival were analyzed by Kaplan-Meier method. A multivariable Cox model for DFS was performed. Pelvic SLNs were retrieved in 100/537 (18.6%) superficial inguinal SLN biopsies and no preoperative factors predicted their presence. In patients with a pelvic SLN, micrometastases were present in 3.0% of pelvic versus 34.0% of superficial inguinal SLN biopsies (P<0.001). There were no differences in groin recurrence, DFS, and disease-specific survival for patients with/without pelvic SLNs in univariate analyses (all P>0.2) or in the multivariable Cox model for DFS (hazard ratio: 1.1, 95% confidence interval: 0.6-2.1). In conclusion, pelvic SLNs harbor micrometastases less frequently than superficial inguinal SLNs do, suggesting that omission of pelvic SLN biopsy may be reasonable.

Is pelvic sentinel node biopsy necessary for lower extremity and trunk melanomas?

OBJECTIVE

There is currently no consensus regarding how to address pelvic sentinel lymph nodes (PSLNs) in melanoma. Thus, our objectives were to identify the incidence and clinical impact of PSLNs.

METHODS

Retrospective review of a prospectively collected multi-institutional melanoma database.

RESULTS

Of 2476 cases of lower extremity and trunk melanomas, 227 (9%) drained to PSLNs (181 to both PSLNs and superficial (inguinal or femoral) sentinel lymph nodes (SSLN) and 46 to PSLNs alone). Seventeen (7.5%) of 227 PSLN cases were positive for nodal metastasis, 8 of which drained to PSLNs only while 9 drained to both PSLNs and SSLNs. Complication rates between PSLN and SSLN biopsy were similar (15% vs. 14% respectively). In 181 cases with drainage to both SSLNs and PSLNs, PSLN biopsy upstaged one patient (0.6%), and completion dissection based on a positive PSLN did not upstage any.

CONCLUSIONS

PSLN biopsy is safe, however in the setting of negative SSLNs there is minimal clinical impact. We therefore recommend PSLN biopsy when the SSLNs are positive or when the tumor drains to PSLNs alone.