Dermoscopy as response evaluation tool for cutaneous malignant melanoma metastases treated with Talimogene Laherparepvec: a prospective feasibility study.

Abstract

Currently, the response of cutaneous melanoma metastases (CMM) to treatment with Talimogene Laherparepvec (T-VEC) is evaluated by clinical examination, macroscopic lesion photography and 3-monthly PET-CT scans. When a complete response (CR) is suspected, biopsies are taken for histopathological confirmation. We set out to investigate the feasibility of dermoscopy in monitoring the response to T-VEC in a pilot study. Six patients with CMM treated with T-VEC monotherapy were enrolled in the pilot study. Patients were treated with T-VEC according to protocol, and the response was monitored with clinical examination, macroscopic lesion photography and 3-monthly PET-CT scans. For this study, 1-3 cutaneous metastases per patient were selected. Macroscopic and dermoscopic pictures of these metastases were taken at baseline, prior to each treatment with T-VEC and prior to histological biopsy. The pictures were evaluated by two investigators, using a colour-based pattern classification. In total, 11 CMM were dermoscopically assessed, 93% was located on the extremities. Four metastases had a blue pattern, two metastases had a pink pattern, three metastases had a brown pattern, and two metastases had mixed patterns. Metastases with a pink pattern harboured glomerular and arborizing vessels that diminished and vanished during treatment T-VEC, indicating CR. The remaining metastases did not show changes on a dermoscopic level that were not also seen on macroscopic level. Five patients achieved CR to T-VEC, one patient is still on treatment. These results suggest that for CMM with a pink pattern, dermoscopy can provide additional information regarding the response to T-VEC. For cutaneous metastases with a blue, brown or a mixed patterns, dermoscopy did not provide additional information on top of the information obtained through physical examination and lesion photography. More studies would be needed to determine the exact role of dermoscopy in the evaluation of CMM.