A higher radiotherapy dose is associated with more durable palliation and longer survival in patients with metastatic melanoma

BACKGROUND. Oncologists are often reluctant to recommend radiotherapy (RT) to palliate metastatic melanoma due to a perception that this tumor is "radio-resistant." The Mayo Clinic experience was analyzed to determine the efficacy of palliative RT. METHODS. Eighty-four consecutive patients with 114 lesions that were not metastatic to the central nervous system (CNS) were evaluated for the response of the presenting symptom, the duration of response, and survival after RT. The median dose delivered was 30 grays (Gy) and the median biologic effective dose (BED) was 39.0 Gy₁₀. Performance status was not uniformly available for all patients. RESULTS. Complete resolution of the presenting symptom occurred in 10 lesions (9%). Of the lesions treated, there was partial improvement in 86 (75%), no change in 12 (11%), and worsening in 6 (5%) lesions. The median survival was 3.8 months and freedom from disease progression (FFP) for individual lesions was 6 months. Patients treated with >30 Gy had significantly longer FFP compared with patients given ≤30 Gy (P = .01). In addition, patients treated with >30 Gy had a significantly longer survival than those given a lesser dose (median of 2 months vs 8 months; P < .0001). Similarly, patients receiving a BED >39.0 Gy₁₀ also were found to have longer FFP (P = .03) and survival (median of 2 months vs 8 months; P < .0001) compared with those receiving a BED ≤39.0 Gy₁₀. The dose per fraction, number of previous therapies, and location of the lesions did not appear to impact the effectiveness of RT. CONCLUSIONS. RT was found to provide effective palliation of non-CNS metastasis from malignant melanoma and should be considered for symptomatic patients. RT doses >30 Gy and a BED >39.0 Gy₁₀ were found to be associated with longer palliation.