Patterns of Metastasis in Merkel Cell Carcinoma

Abstract

Background. Merkel cell carcinoma (MCC) is a cutaneous neuroendocrine malignancy with a propensity for regional and distant spread. Because of the relative infrequency of this disease, the patterns of metastasis in MCC are understudied. Methods. Patients with American Joint Committee on Cancer (8th edition) stage I-IV MCC treated at our institution were identified (1/1/2008-2/28/2018). The first site of metastasis was classified as regional [regional lymph node (LN) basin, in-transit] or distant. Distant metastasisfree (DMFS) and MCC-specific (MSS) survival were estimated. Results. Of 133 patients, 64 (48%) had stage I, 13 (10%) stage II, 48 (36%) stage III, and 8 (6%) stage IV disease at presentation. The median follow-up time in patients who remained alive was 36 (interquartile range 20-66) months. Regional or distant metastases developed in 78 (59%) patients. The first site was regional in 87%, including 73% with isolated LN involvement, and distant in 13%. Thirtyseven (28%) patients eventually developed distant disease, which most commonly involved the abdominal viscera (51%) and distant LNs (46%) first. The lung (0%) and brain (3%) were rarely the first distant sites. Stage III MCC at presentation was significantly associated with worse DMFS (hazard ratio 4.87, P = 0.001) and stage IV disease with worse MSS (hazard ratio 6.30, P = 0.002).

Nationwide multidisciplinary consensus on the clinical management of Merkel cell carcinoma: a Delphi panel

“…The literature highlights that such approach has a major influence on treatment management in most cases leading to a significant modification of an established treatment plan. 53 The panelists agreed that cases of MCC be discussed and referred to dedicated centers as soon as possible. The improvement in new therapeutical opportunities for this rare pathology needs expertize and multidisciplinarily approach.…”

“…26 65 Testing MCPyV antibody can optimize surveillance in conjunction with imaging studies; an increasing titer prompts imaging studies to confirm and localize recurrence in a timely manner, while a decreasing titer indicates that there is no recurrence or that the cancer is reduced significantly. 53 Imaging plays a crucial role in diagnosis and initial staging, planning for surgery or radiation therapy, assessment of treatment response and surveillance of recurrence and metastases. 66 Moreover, in locally advanced disease or distant metastases, imaging plays an important role in determining the location of the primary tumor and identifying the local-regional invasion to guide surgical or radiation therapy, in particular in the head and neck, due to its anatomic complexity.…”

Merkel cell carcinoma: An updated review of pathogenesis, diagnosis, and treatment options

“…The most common locations for metastases are the distant lymph nodes and intra-abdominal organs. 79,80 There is no single documented approach for the treatment of patients with metastatic MCC, and thus the NCCN currently recommends that these patients enroll in a clinical trial if possible, have their case reviewed by a multidisciplinary tumor board, and undergo comprehensive imaging. 37 Most patients with metastatic MCC receive treatment with systemic therapy, radiation therapy, surgery, or a combination of these three.…”

Survival outcomes and epidemiology of Merkel cell carcinoma of the lower limb and hip: A Surveillance, Epidemiology, and End Results analysis 2000-2018

“… 9 , 10 Although UV-mutational MCC is known to be aggressive, with high regional invasion and metastasis rates, MCPyV-linked MCC might behave differently. 8 , 11 , 12 …”