Robotic Stereotactic Radiosurgery in Melanoma Patients with Brain Metastases under Simultaneous Anti-PD-1 Treatment

Area of Science:

• Oncology
• Radiology
• Immunotherapy

Background:

• Combination therapy of radiotherapy and immune checkpoint inhibition is gaining interest.
• Melanoma brain metastases present a significant clinical challenge.

Purpose of the Study:

• To evaluate imaging findings, acute toxicity, and local control in melanoma patients with brain metastases treated with stereotactic radiosurgery (SRS) alone or combined with anti-programmed death 1 (PD-1) therapy.
• To assess the safety and efficacy of combined radioimmunotherapy.

Main Methods:

• Retrospective analysis of 26 patients with melanoma brain metastases treated with SRS alone (n=13) or SRS + anti-PD-1 therapy (n=13).
• Volumetric assessment of lesion size using cranial magnetic resonance imaging (cMRI) at 3 and 6 months post-SRS.
• Toxicity assessment using Common Terminology Criteria for Adverse Events (CTCAE) up to 12 weeks.

Main Results:

• Local control at 6 months was comparable: 80% for SRS alone and 86% for SRS + anti-PD-1 therapy.
• All reported toxicities were grade 2 or less, indicating a safe toxicity profile.
• Pseudoprogression (PsP) was observed in 23% of patients receiving SRS + anti-PD-1 therapy, characterized by initial lesion increase followed by regression.

Conclusions:

• Stereotactic radiosurgery (SRS) can be safely combined with anti-programmed death 1 (PD-1) antibodies in melanoma patients with cerebral metastases.
• Early volumetric progression in combined treatment may represent pseudoprogression (PsP), complicating treatment evaluation.
• Combined radioimmunotherapy for melanoma brain metastases requires experienced teams for optimal assessment and management.