Palliative radiotherapy for recurrent and metastatic malignant melanoma: Prognostic factors for tumor response and long-term outcome: A 20-year experience

Purpose: Radiotherapy is used as a "last resort" for patients with advanced cutaneous malignant melanoma. We have analyzed our 20-year clinical experi ence with respect to different endpoints and prognostic factors in patients with locally advanced, recurrent, or metastatic malignant melanoma. Methods: From 1977 to 1995, 2,917 consecutive patients were entered in the melanoma registry of our hospital. Radiotherapy was indicated in 121 patien ts (56 females, 65 males) for palliative reasons in advanced malignant mela noma stages UICC IIB/III/IV. The histology of the primary lesion was nodula r in 51 patients, superficial spreading in 35, acral-lentiginous in 8, and lentigo maligna melanoma in 4 patients. Eleven patients had primary or recu rrent lesions which were either not eligible for surgery or had residual di sease (R2) after resection of a primary or recurrent lesion (UICC IIB); 57 patients had lymph node (n = 33) or in-transit metastases (n = 24) (UICC II I), and 53 had distant organ metastases (7 M1a; 46 M1b) (UICC IV). Time fro m first diagnosis to on-study radiotherapy averaged 19 (median: 18; range: 3-186) months. In most cases, conventional RT was applied with 2-6 Gy singl e fractions up to a median total radiation dose of 48 (mean: 45; range: 20- 66) Gy. Results: At 3 months follow-up, complete response (CR) was achieved in 7 (6 4%) and overall response [complete (CR) and partial response (PR)] in all ( 100%) UICC IIB patients, in 25 (44%) and 44 (77%) of 57 UICC III patients, and in 9 (17%) and 26 (49%) of 53 UICC IV patients. Tumor progression durin g radiotherapy occurred in 25 (21%) patients. Patients with CR survived lon ger (median: 40 months) than those without CR (median 10 months) (p < 0.01) . At last follow-up (Dec 31, 1996), 26 patients were still alive: 6 (55%) U ICC IIB, 17 (30%) UICC III, and 3 (6%) UICC IV patients (p < 0.01). Univari ate analysis revealed the following prognostic factors for complete respons e and long-term survival: UICC stage (p < 0.001), primary location in the h ead and neck region, total radiation dose above 40 Gy (all p < 0.05), while age, gender, and histology had no impact. In multivariate analysis, UICC s tage was the only independent prognostic factor (p < 0.001). Conclusion: External beam radiotherapy can provide long-term local control and effective palliation in malignant melanoma UICC stages IIB-IV. The curr ent UICC staging system is an excellent prognostic factor for initial and l ong-term tumor response in metastatic melanoma. Therefore, prospective rand omized trials using external radiotherapy with or without adjuvant therapy for advanced malignant melanoma are justified.