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

BACKGROUND: 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. OBJECTIVES: We set out to investigate the feasibility of dermoscopy in monitoring the response to T-VEC in a pilot study. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

The value of lymph node ultrasound and whole body 18F-FDG PET/CT in stage IIB/C melanoma patients prior to SLNB.

BACKGROUND: Stage IIB/IIC (8th AJCC) melanoma patients are known to have high-risk primary tumors, however they follow the same routine to sentinel lymph node biopsy (SLNB) as more low risk tumors. Guidelines are not conclusive regarding the use of preoperative imaging for these patients. The aim of this pilot study was to assess the value of ultrasound (US) and 18F-FDG PET/CT prior to lymphoscintigraphy (LSG) and SLNB for stage IIB/C melanoma patients. METHODS: From 2019-04 till 2020-01, all stage IIB/C melanoma patients underwent US of the regional lymph nodes and whole body 18F-FDG PET/CT before their planned LSG and SLNB. Suspected metastases were confirmed with fine needle aspiration (FNA), prior to surgery. RESULTS: In total 23 patients were screened: six had metastases detected by imaging, two by US, one by 18F-FDG PET/CT and three were detected by both imaging modalities. All metastases were nodal and therefore treatment was altered to lymph node dissection and all but one also received adjuvant therapy. Eight (47%) of the 17 patients without macroscopic disease, still had a positive SN. Sensitivity, specificity and false negative rate for US and 18F-FDG PET/CT were 36%, 89%, 64% and 29%, 100% and 71%, respectively. CONCLUSION: Preoperative negative imaging does not exclude the presence of SN metastases, therefore SLNB cannot be foregone. However, US detected metastases in 22% of patients, altering their treatment, which suggests it is effective in the work-up of stage IIB/C melanoma. Staging with 18F-FDG PET/CT is not of added value prior to LSG and SLNB and should therefore not be used.