Outcomes after stereotactic radiosurgery of brain metastases in patients with malignant melanoma and validation of the melanoma molGPA

Abstract

Introduction Malignant melanoma is the third most common primary in the diagnosis of brain metastases. Stereotactic radiosurgery (SRS) is a well-established treatment option in limited brain disease. We analyzed outcomes of SRS with a particular focus on the graded prognostic assessment (GPA, melanoma molGPA), prognostic factors, and toxicity. Methods We evaluated 173 brain metastases in 83 patients with malignant melanoma. All were treated with SRS median dose of 20 Gy prescribed to the 80 or 100% isodose line between 2002 and 2019. All patients were followed-up regularly, including contrast‐enhanced brain imaging as well as clinical examination, initially 6 weeks after treatment, then in quarterly follow-up. Results The median age was 61 years (range 27–80); 36 female and 47 male patients were treated. After a median follow-up of 5.7 months, median OS (overall survival) was 9.7 months 95%-KI 4.7–14.7). LC (local control) at 6 months, 12, 24 months was 89%, 86%, and 72%, respectively (median was not reached). Median DBC (distant brain control) was 8.2 months (95%-KI 4.7–11.7). For OS, a KPS ≥ 80%, a positive BRAF mutation status, a small PTV (planning target volume), the absence of extracranial metastases, as well as a GPA and melanoma molGPA > 2 were prognostic factors. In the MVA, a small PTV and a melanoma molGPA > 2 remained significant. Conclusion The present survival outcomes support the use of the disease-specific melanoma molGPA as reliable prognostic score. Favorable outcomes for SRS compared to other studies were observed. In the treatment of brain metastases of malignant melanoma patients, a multidisciplinary approach consisting of surgery, SRS, chemotherapy, and immunotherapy should be considered.

Management of intracranial melanoma metastasis with radiosurgery: a case report and literature review

“…Patients with solid tumors often present with metastases to the central nervous system; among the theraoptions for the treatment of brain metastases are local strategies such as surgery, stereotactic radiosurgery, or holoencephalic radiotherapy to define what type of treatment is appropriate for each patient. It is necessary to individualize each case according to age, the number of intracranial metastases and extracranial metastatic involvement, the probability of survival, and the patient's functional status 3 .…”

“…Brain metastases from malignant melanoma are classically considered radioresistant to conventional fractionated external radiation therapy and holocranial radiotherapy. However, during the last decade, stereotactic radiosurgery has become an effective treatment modality for selected patients (1-4 metastases that measure < 3-4 cm) 3 .…”