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

Abstract

Purpose: Radiotherapy is used as a "last resort" for patients with advanced cutaneous malignant melanoma. We have analyzed our 20-year clinical experience 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 patients (56 females, 65 males) for palliative reasons in advanced malignant melanoma stages UICC IIB/III/IV. The histology of the primary lesion was nodular in 51 patients, superficial spreading in 35, acral-lentiginous in 8, and lentigo maligna melanoma in 4 patients. Eleven patients had primary or recurrent lesions which were either not eligible for surgery or had residual disease (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 III), and 53 had distant organ metastases (7 M1a; 46 M1b) (UICC IV). Time from 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 single 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 (64%) 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 during radiotherapy 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 follow-up (Dec 31, 1996), 26 patients were still alive: 6 (55%) UICC IIB, 17 (30%) UICC III, and 3 (6%) UICC IV patients (p < 0.01). Univariate analysis revealed the following prognostic factors for complete response and long-term survival: UICC stage (p < 0.001), primary location in the head 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 stage 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 current UICC staging system is an excellent prognostic factor for initial and long-term tumor response in metastatic melanoma. Therefore, prospective randomized trials using external radiotherapy with or without adjuvant therapy for advanced malignant melanoma are justified.