Long term results following radiation therapy of locally recurrent and metastatic malignant melanoma

The 20-year radiotherapy (RT) experience in patients with locally advanced, recurrent or metastatic malignant melanoma (MM) is analyzed with respect t o different endpoints and prognostic factors. From 1977 to 1995, 2917 conse cutive patients were entered in our MM registry. RT was indicated in 721 pa tients (56 females, 65 males) for palliation in advanced MM stages. The his tology 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 les ions which were ineligible for surgery or had residual disease (R2) after r esection 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 m etastases (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 conventiona l 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 respons e (CR) was achieved in 7 (64%) and overall response (CR+PR) in all(100%) UI CC 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 (2 1%) patients. Patients with CR survived longer (median:40 months) than thos e without CR (median:10 months) (p<0.01). At last FU, 26 patients were aliv e: 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 hea d and neck and total dose >40 Gy (all p<0.05); age, gender and histology ha d no impact. In multivariate analysis, UICC stage was the only independent favorable prognostic factor for CR and long-term survival (p<0.001). Extern al RT provides effective palliation and long-term local tumor control in ad vanced UICC stages. UICC staging is a good predictor for initial and long-t erm response in metastatic MM. Prospective randomized trials using RT with or without adjuvant therapy for advanced MM are justified.