Analysis of Prognostic Factors from 9387 Merkel Cell Carcinoma Cases Forms the Basis for the New 8th Edition AJCC Staging System

Abstract

Analysis of a national dataset of MCC cases validates the predictive value of disease extent at presentation. Separation of clinical and pathological stage groups and regrouping of unknown primary tumors are supported by the analysis. The revised staging system provides more accurate prognostication and has been formally accepted by the AJCC staging committee for inclusion in the 8th edition.

The diagnostic utility of Merkel cell polyomavirus immunohistochemistry in a fine needle aspirate of metastatic Merkel cell carcinoma of unknown primary to the pancreas

“…The highest anatomical distributions are the head and neck (43%), extremities (39%), and trunk (11%). 4 Several large studies from the National Cancer…”

“…4 MCC has high propensity for loco-regional recurrence and distant metastases to lymph nodes, skin, lung, brain, bone, and liver. 23 However, metastases to the pancreas are exceedingly rare; only 19 cases have been reported in the literature.…”

“…Yet about 4%-14% of MCCs manifest as nodal or metastatic disease without a detectable primary tumor. [4][5][6] Pancreatic involvement by MCC is rare with 19 reported cases in the literature. [7][8][9][10][11][12][13][14][15][16][17][18][19] To date, only 8 cases have been diagnosed by endoscopic ultrasound-guided fine-needle aspiration cytology (EUS-FNA).…”

Metastatic Merkel-cell carcinoma: the dawn of a new era

“…Despite an often delayed diagnosis at presentation, the majority of cases are local (65%) with only a minority having distant disease (8%) 9. However, it is important to diagnose MCC early because the 5-year overall survival drops from 63% for Stage I disease to just 14% for Stage IV 9…”

Epidemiology, biology and therapy of Merkel cell carcinoma: conclusions from the EU project IMMOMEC

“…This allowed enrollment of more than 600 MCC patients into a prospective clinical database, establishment of an extensive tumor repository and development of a robust translational research program [59]. Clinical data and expertise from this large MCC center have contributed to the development of the new 8th edition American Joint Committee on Cancer (AJCC) MCC staging system [60]. This revised staging system will include a separate stage group for patients with metastatic MCC with unknown primary tumor, who carry a more favorable prognosis compared to patients presenting with concurrent primary and nodal metastatic disease.…”