Abstract
Objectives: To present the clinical course of a patient with painful oligometastatic melanoma with stereotactic body radiation therapy (SBRT) concurrently with immune checkpoint inhibition, resulting in a durable response with symptom relief, radiographic complete metabolic response, and negative circulating tumor deoxyribonucleic acid (ctDNA). The objective of the case report is to highlight SBRT as a practical and effective option for administering combined modality therapy in a rural community setting, where geographic and logistical challenges may limit access to surgery. Our objective is to illustrate the potential synergy between SBRT and systemic immunotherapy to achieve durable control of metastatic melanoma, including complete metabolic and biomarker remission.
Methods: A case report was conducted of a 68-year-old woman with primary cutaneous melanoma of the lower back who presented with progressive, painful right groin and abdominal wall subcutaneous masses. Diagnostic ultrasound and biopsy confirmed metastatic melanoma. Staging positron emission tomography (PET-CT) demonstrated subcutaneous metastases in the right posterior abdominal wall and right groin consistent with Stage IV (pT2bN0M1a) melanoma. She was initiated on dual immune checkpoint therapy. Because of the focal pain, travel limitations due to distance from the surgical center, the patient declined surgical excision. SBRT to a dose of 40 Gy in 5 fractions was administered, followed by maintenance immunotherapy. Surveillance included symptom assessment, PET-CT, MRI brain, and ctDNA testing.
Results: Following SBRT, the patient experienced rapid improvement in localized pain after completion of radiation therapy. PET-CT interval imaging studies showed progressive reduction in the size and metabolic activity of the subcutaneous metastatic deposits, resulting in complete metabolic response. During surveillance, serial brain imaging and ctDNA remained negative for progression, with no new metastases. A durable complete response after treatment has been sustained for more than 1 year with continuous absence of radiographic or biochemical recurrence.
Conclusion(s): Combining SBRT in conjunction with immune checkpoint inhibition resulted in rapid symptom relief, radiologic tumor regression, and a durable complete metabolic response with persistent ctDNA negativity in a patient with oligometastatic melanoma who declined surgery due to geographic barriers. This case demonstrates the feasibility of a community radiation oncology practice in delivering advanced treatment and supports emerging evidence of synergy between immunotherapy and focal radiation therapy with SBRT. Further investigation is needed to clarify optimal patient selection, sequencing, and integration of SBRT with immunotherapy in oligometastatic melanoma.
