Brazilian Society of Surgical Oncology recommendations on Merkel cell carcinoma surgical treatment

Abstract

Background: Merkel cell carcinoma (MCC) is a rare neuroendocrine skin cancer with poor 5-year survival rates. Surgery and radiation are the current first-line treatments for local and nodal disease.

Objectives: The Brazilian Society of Surgical Oncology developed this document aiming to guide the surgical oncology role in multimodal MCC management.

Methods: The consensus was established in three rounds of online discussion, achieving consensus on specific topics including diagnosis, staging, treatment, and follow-up.

Results: Patients suspected of having MCC should undergo immunohistochemical examination and preferably undergo pathology review by a dermatopathologist. Initial staging should be performed with dermatologic and nodal physical examination, combined with complementary imaging. Whole-body imaging, preferably with positron emission tomography (PET) or computed tomography (CT) scans, are recommended. Due to the need for multidisciplinary approaches, we recommend that all cases should be discussed in tumor boards and referred to other specialties as soon as possible, reducing potential treatment delays. We recommend that all patients with clinical stage I or II may undergo local excision associated with sentinel lymph node biopsy. The decision on margin size should consider time to recovery, patient's comorbidities, and risk factors. Patients with positive sentinel lymph nodes or the presence of risk factors should undergo postoperative radiation therapy at the primary site. Exclusive radiation is a viable option for patients with low performance. Patients with positive sentinel lymph node biopsy should undergo nodal radiation therapy or lymphadenectomy. In patients with nodal clinical disease, in addition to primary tumor treatment, nodal radiation therapy and/or lymphadenectomy are recommended. Patients with advanced disease should preferably be enrolled in clinical trials and discussed in multidisciplinary meetings. The role of surgery and radiation therapy in the metastatic/advanced setting should be discussed individually and always in tumor boards.

Conclusion: This document aims to standardize a protocol for initial assessment and treatment for Merkel cell carcinoma, optimizing oncologic outcomes in middle-income countries such as Brazil.

Keywords: Merkel cell; consensus; surgery.