BRAF testing timelines and impact on the starting of systemic treatment.

Abstract

e21575 Background: Targeted therapy with BRAF and MEK inhibitors constitute part of the standard treatment for BRAF V600 mutated melanoma. Timely detection of BRAF mutation is necessary for clinicians and patients to make treatment decisions. We aimed to map the BRAF testing timelines from the time of request until the reported result in order to assess obstacles to timely BRAF reporting in our community, and its impact on the initiation of systemic therapy. Methods: In this single-center retrospective study, we included adult patients referred to the Medical Oncology Department at the Princess Margaret Cancer Centre (PM) from January 2019 to August 2019 with histologically confirmed cutaneous or mucosal melanoma and BRAF molecular testing performed in 2019. The Log-Rank method was applied to detect differences in BRAF turnaround time and time to treatment initiation in specified subgroups. A p value < 0.05 was considered statistically significant. Results: Sixty-six cases were identified. The median age was 64 (24-88), and 42 (64%) were male. At the time of BRAF request, 10 (15%) patients had stage II, 33 (50%) had stage III, and 23 (35%) had stage IV disease. Twenty-eight (43%) were positive for the BRAF V600E/K mutation by ARMS assay and 4 (6%) for other variants by NGS test. Thirty-three (50%) patients had the BRAF test available at their first PM Medical Oncology visit. Median time between BRAF request and result was 17 days; when a reflex BRAF test was ordered by the Pathology Department, the median turnaround time was 12 days (95% CI 8-15), compared to 20 days (95% CI 16-23) if the order was requested by another specialist ( p < 0.001). Median time to transfer samples between institutions was 6 days. If the BRAF test was processed within the institution where the biopsy was performed, the BRAF median turnaround time was 13 days (95% CI 6-19) compared to 19 days (95% CI 16-21) if a sample was transferred to another institution ( p = 0.02). In total, 49 patients had systemic therapy. Median time between the first visit with Medical Oncology and treatment initiation was 29 days and was not statistically different if the BRAF result was available or not (28 vs. 34 days; p = 0.09). In the subgroup with stage IV disease (Table), 20 patients received systemic therapy; the median time to treatment initiation was 24 days and differed with BRAF result availability (20 vs. 31 days, p = 0.03). Conclusions: The current BRAF testing timeline at the PM varies from days to weeks. A major factor impacting this timeline is transfer time, which can be streamlined by pathology reflex testing. Delays in turnaround time appears to impact subsequent timing and type of therapeutic interventions, especially in patients with stage IV disease.[Table: see text]