ABSTRACT
PURPOSE: Melanoma brain metastases (BMs) are associated with poor survival. Combination immune checkpoint inhibitors (ICIs) with anti-PD1 and anti-CTLA-4 are the international standard-of-care treatment. Most landmark clinical trials excluded real-world patients with symptomatic disease, poor performance status (PS), and steroid use. Despite the high incidence of melanoma in New Zealand (NZ), the only publicly funded systemic treatment is anti-PD1 monotherapy. The real-world outcomes for BMs after ICIs in NZ are unknown. METHODOLOGY: Medical records of patients with melanoma BMs in seven cancer centers across NZ between September 1, 2016, and September 1, 2020, were evaluated. Clinicopathologic characteristics, treatment, intracranial (IC) tumor response rates, IC progression-free survival, and overall survival (OS) are reported. RESULTS: One hundred and forty-four patients received at least one dose of ICI. One hundred and thirty-three (93%) patients received anti-PD1 monotherapy. Almost a quarter of patients had poor baseline PS, 56% were symptomatic, and 33% had corticosteroids. Patients also received local therapies: 61 (42%) patients underwent surgery, 42 (29%) received whole brain radiation, and 47 (33%) received stereotactic radiation. The median OS was 15 months, and a third of patients were alive at 2 years. The toxicity of ICIs was at 28% and 15% for Common Terminology Criteria for Adverse Events grade 1-2 and 3-4 events, respectively. Of the patients who are still alive, 76% of patients remained symptomatic neurologically at last follow-up. CONCLUSION: Most patients in this NZ real-world study were symptomatic and received anti-PD1 monotherapy. Approximately one-third of treated patients are alive at 2 years, but most patients remained symptomatic. This highlights the need for more effective treatment and prospective management of their neurologic rehabilitation needs.
ABSTRACT
The treatment of melanoma has been revolutionised in recent years by advances in the understanding of the genomic landscape of this disease, which has led to the development of new targeted therapeutic agents, and the ability to therapeutically manipulate the immune system through inhibition of cancer cell-T-cell interactions that prevent an adaptive immune response. While these therapeutic interventions have dramatically improved the prospects of survival for patients with advanced melanoma, they bring significant complexity to the interpretation of therapeutic response because their mechanisms and temporal profile of response vary considerably. In this review, we discuss the mode of action of these emerging therapies and their toxicities to provide a framework for the use of FDG PET/CT in therapeutic response assessment. We propose that the greatest utility of PET in assessment of response to agents that abrogate signalling related to BRAF mutation is for early assessment of resistance, while in anti-CTLA4 therapy, immunological flare can compromise early assessment of response but can identify potentially life-threatening autoimmune reactions. For anti-PD1/PDL1 therapy, the role of FDG PET/CT is more akin to its use in other solid malignancies undergoing treatment with conventional chemotherapy. However, further research is required to optimise the timing of scans and response criteria in this disease.
