Melanoma metastases to the neck nodes: role of adjuvant irradiation.

Abstract

To review experiences in the treatment of regionally advanced melanoma to the neck and/or parotid with emphasis on the role of adjuvant radiotherapy. Clinical and histopathologic data, treatment details, and outcomes in patients treated during the period 2000-2006 at the Institute of Oncology, Ljubljana, Slovenia, were reviewed. A total of 40 patients with 42 dissections underwent surgery, and 43 patients with 45 dissections received irradiation postoperatively to a median equivalent dose (eqTD(2): 2 Gy/fraction, 1 fraction/day, 5 fractions/week) of 60 Gy (range, 47.8-78.8). Regional control 2 years after surgery was 56% (95% confidence interval [CI] 40-72%) and after postoperative radiotherapy 78% (CI 63-92%) (p = 0.015). On multivariate analysis, postoperative radiotherapy (yes vs. no: hazard ratio [HR] 6.3, CI 2.0-20.6) and sum of the risk factors present (i.e., risk factor score; HR 1.7 per score point, CI 1.2-2.6) were predictive for regional control. On logistic regression testing, the number of involved nodes was associated with the probability of distant metastases (p = 0.021). The incidence of late toxicity did not correlate with the mode of therapy, eqTD(2), or fractionation pattern. Adjuvant radiotherapy has the potential to compensate effectively for the negative impact of adverse histopatologic features to disease control in a dissected nodal basin. More conventionally fractionated radiotherapy regimens using fraction doses of 2-2.5 Gy, with cumulative eqTD(2)> or =60 Gy, are recommended. The number of involved lymph nodes is proposed as an additional criterion for limiting the implementation of adjuvant irradiation.