Long term results following radiation therapy of locally recurrent and metastatic malignant melanoma [Langzeitergebnisse nach strahlentherapie beim lokal rezidivierten und metastasierten malignen melanom]

The 20-year radiotherapy (RT) experience in patients with locally advanced, recurrent or metastatic malignant melanoma (MM) is analyzed with respect to different endpoints and prognostic factors. From 1977 to 1995, 2917 consecutive patients were entered in our MM registry. RT was indicated in 121 patients (56 females, 65 males) for palliation in advanced MM stages. The histology of the primary lesion was nodular in 51, superficial spreading in 35, acral-lentiginous in 8 and lentigo maligna in 4 patients); 22 were missing or could not be reclassified. Eleven patients had primary or recurrent lesions which were ineligible for surgery or had residual disease (R2) after resection of a primary or recurrent lesion (UICC IIB); 57 patients had lymph node (33) or in-transit metastases (24) (UICC III), 53 had distant organ metastases (7 M1a; 46 M1b) (UICC IV). Time from first diagnosis to on- study RT averaged 19 (median: 18; range: 3-186) months. In most cases conventional RT was applied (2-6 Gy single fractions) up to a mean total RT dose of 45 (median:48; range:20-66) Gy. At 3 months follow-up (FU), complete response (CR) was achieved in 7 (64%) and overall response (CR+PR) in all (100%) UICC IIb patients, in 25 (44%)/44 (77%) of 57 UICC III patients, and in 9 (17%)/26 (49%) of 53 UICC IV patients. Progression during RT occurred in 25 (21%) patients. Patients with CR survived longer (median: 40 months) than those without CR (median: 10 months) (p<0.01). At last FU, 26 patients were alive:6 (55%) UICC IIB, 17 (30%) UICC III, and 3 (6%) UICC IV patients (p<0.01). In univariate analysis following favorable prognostic factors for CR and longterm survival were identified: low UICC stage (p<0.001), primary site head and neck and total dose >40 Gy (all p<0.05); age, gender and histology had no impact. In multivariate analysis, UICC stage was the only independent favorable prognostic factor for CR and long-term survival (p<0.001). External RT provides effective palliation and long-term local tumor control in advanced UICC stages. UICC staging is a good predictor for initial and long-term response in metastatic MM. Prospective randomized trials using RT with or without adjuvant therapy for advanced MM are justified.