Nodal basin recurrence following lymph node dissection for melanoma: Implications for adjuvant radiotherapy

Purpose: To analyze patterns of failure in malignant melanoma patients with lymph node involvement who underwent complete lymph node dissection (LND) of the nodal basin, To determine prognostic factors predictive of local rec urrence in the lymph node basin in order to select patients who may benefit from adjuvant radiotherapy. Methods and Materials: A retrospective analysis of 338 patients undergoing complete LND for melanoma between 1970 and 1996 ho had pathologically invol ved lymph nodes was performed. Mean follow-up from the time of LND was 54 m onths (range: 12-306 months). Lymph node basins dissected included the neck (56 patients), axilla (160 patients), and groin (122 patients), Two hundre d fifty-three patients (75%) underwent therapeutic LND for clinically invol ved nodes, while 85 patients (25%) had elective dissections. Forty-four per cent of patients received adjuvant systemic therapy. No patients received a djuvant radiotherapy to the lymph node basin. Results: Overall and disease-specific survival for all patients at 10 years was 30% and 36%, respectively. Overall nodal basin recurrence was 30% at 1 0 years. Mean time to nodal basin recurrence was 12 months (range: 2-78 mon ths). Site of nodal involvement was prognostic with 43%, 28%, and 23% nodal basin recurrence at 10 years with cervical, axillary, and inguinal involve ment, respectively (p = 0.008). Extracapsular extension (ECE) led to a 10-y ear nodal basin failure rate of 63% vs. 23% without ECE (p < 0.0001). Patie nts undergoing a therapeutic dissection for clinically involved nodes had a 36% failure rate in the nodal basin at 10 years, compared to 16% for patie nts found to have involved nodes after elective dissection (p = 0.002). Lym ph nodes larger than 6 cm led to a failure rate of 80% compared to 42% for nodes 3-6 cm and 24% for nodes less than 3 cm (p < 0.001). The number of ly mph nodes involved also predicted for nodal basin failure with 25%, 46%, an d 63% failure rates at 10 years for 1-3, 4-10, and >10 nodes involved (p = 0.0001). There was no significant difference in nodal basin control in pati ents with synchronous or metachronous lymph node metastases, nor in patient s receiving or not receiving adjuvant systemic therapy. Nodal basin failure was predictive of distant metastasis with 87% of patients with nodal basin recurrence developing distant disease compared to 54% of patients without nodal failure (p < 0.0001). On multivariate analysis, number of positive no des and type of dissection (elective vs. therapeutic) were significant pred ictors of overall and disease-specific survival. Size of the largest lymph node was also predictive of disease-specific survival. Site of nodal involv ement and ECE were significant predictors of nodal basin failure. Conclusions: Malignant melanoma patients with nodal involvement have a sign ificant risk of nodal basin failure after LND if they have cervical involve ment, ECE, >3 positive lymph nodes, clinically involved nodes, or any node larger than 3 cm, Patients with these risk factors should be considered for adjuvant radiotherapy to the lymph node basin to reduce the incidence of n odal basin recurrence. Patients with nodal basin failure are at higher risk of developing distant metastases. (C) 2000 Elsevier Science Inc.