Surgical Therapy of Merkel Cell Carcinoma—Single Centre Experience of 157 Patients in Germany

To the Editor,

Merkel cell carcinoma (MCC) is a rare neuroendocrine malignancy with a low incidence between 0.3/100000/year and 1.6/100000/year but with high mortality. ¹ The classification of tumour stages depends on the diameter of the primary tumour (stage I: <2 cm, stage II: >2 cm), metastatic spread into regional lymph nodes (stage III), and distant metastasis (stage IV). ¹ The 5-year survival is reported to be 50.6% for local disease, 35.4% for nodal disease, and 13.5% for distant disease. ¹ Surgical therapy remains the basis of management for MCC including primary excision and locoregional evaluation by sentinel node biopsy (SNB). Techniques of micrographically controlled surgery (MCS) like Mohs surgery or 3D histology offer a superior alternative to wide local excision with higher rates of complete tumour removal. ² Dissection of the regional lymph nodes is recommended in case of clinically or sonographically suspect lymph nodes and might be usefully supplemented by radiotherapy and checkpoint inhibitors.^3-5 The aim of the study was to evaluate surgical therapy of MCC patients in a dermatosurgical centre.

We included 157 patients who received treatment between 2009 and 2019 for MCC at the Department of Dermatology (University Hospital Tuebingen). All patients with sonographically confirmed N0 status were offered a SNB. Every indication was based on individual assessment in the interdisciplinary tumour board. For patient’s details see Supplementary Table S1.

One hundred thirty-eight patients underwent reexcision of the primary MCC; in 119 patients MSC was used and R0 resection was achieved in 114 cases (average of 1.3 surgeries). SNB was performed in 111 patients and was successful in 99 patients (89%). Cervical identification rate was 84.8%. Metastases were found in 19% of sentinel nodes. A large tumour diameter was significantly associated with an increased risk of metastasis (P < .0001).

A total of 100 patients received further therapies [n = 75 (48%): mono-radiotherapy, n = 4 (3%): mono-chemotherapy, n = 12 (8%): combined radio-chemotherapy, n = 27 patients (17%): immunotherapy].

Tumour diameter was associated with increased all-cause mortality (P < .0001) with most evident difference for T3 tumours [(American Joint Committee on Cancer (AJCC) classification, 8th edition]. No significant difference for patients with positive or negative sentinel node was observed (P = .71) regarding all-cause mortality.

Patients who received SNB showed increased survival; however, these patients were younger and had smaller tumour diameters. MCS in tumescent local anesthesia is a feasible option for MCC.

Supplemental Material

sj-docx-1-cms-10.1177_12034754231217208 – Supplemental material for Surgical Therapy of Merkel Cell Carcinoma—Single Centre Experience of 157 Patients in Germany

Supplemental material, sj-docx-1-cms-10.1177_12034754231217208 for Surgical Therapy of Merkel Cell Carcinoma—Single Centre Experience of 157 Patients in Germany by Martin Heister, Hans-Martin Häfner, Julian Neuner, Katrin Kofler, Claudia Schulz and Lukas Kofler in Journal of Cutaneous Medicine and Surgery