Merkel cell cancer staging

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vamsikrishna Gunnam M.B.B.S [2] Ahmad Al Maradni, M.D. [3]

Overview

The staging of merkel cell cancer is based on the TNM staging system.

Staging

According to the TNM staging system, merkel cell cancer is classified into 4 stages based on the following:
- Tumor size
- Involvement of lymph nodes
- Metastasis
The stages of merkel cell carcinoma are shown in the table below:^[1]^[2]^[3]^[4]

Stage	Primary Tumor (T)	Lymph Node (N)	Metastasis (M)
0	In situ	No regional lymph node metastasis	No distant metastasis
IA	≤2 cm	Nodes negative by pathologic exam	No distant metastasis
IB	≤2 cm	Nodes negative by clinical exam (no pathologic node exam performed)	No distant metastasis
IIA	>2 cm	Nodes negative by pathologic exam	No distant metastasis
IIB	>2 cm	Nodes negative by clinical exam (no pathologic node exam performed)	No distant metastasis
IIC	Invades bone, muscle and cartilage	No regional lymph node metastasis detected	No distant metastasis
IIIA	Any size tumor (includes invading tumors)	Micrometastasis (which are diagnosed after sentinel or elective lymphadenectomy)	No distant metastasis
IIIB	Any size tumor (includes invading tumors)	Positive for: Macrometastasis In transit metastasis	No distant metastasis
IV	Any size tumor (includes invading tumors)	Any lymph node metastasis	Metastasis beyond regional lymph nodes

References

↑ Harms KL, Healy MA, Nghiem P, Sober AJ, Johnson TM, Bichakjian CK, Wong SL (October 2016). “Analysis of Prognostic Factors from 9387 Merkel Cell Carcinoma Cases Forms the Basis for the New 8th Edition AJCC Staging System”. Ann. Surg. Oncol. 23 (11): 3564–3571. doi:10.1245/s10434-016-5266-4. PMID 27198511.
↑ Lemos BD, Storer BE, Iyer JG, Phillips JL, Bichakjian CK, Fang LC, Johnson TM, Liegeois-Kwon NJ, Otley CC, Paulson KG, Ross MI, Yu SS, Zeitouni NC, Byrd DR, Sondak VK, Gershenwald JE, Sober AJ, Nghiem P (November 2010). “Pathologic nodal evaluation improves prognostic accuracy in Merkel cell carcinoma: analysis of 5823 cases as the basis of the first consensus staging system”. J. Am. Acad. Dermatol. 63 (5): 751–61. doi:10.1016/j.jaad.2010.02.056. PMC 2956767. PMID 20646783.
↑ Foote M, Veness M, Zarate D, Poulsen M (September 2012). “Merkel cell carcinoma: the prognostic implications of an occult primary in stage IIIB (nodal) disease”. J. Am. Acad. Dermatol. 67 (3): 395–9. doi:10.1016/j.jaad.2011.09.009. PMID 22030017.
↑ Rastrelli M, Ferrazzi B, Cavallin F, Chiarion Sileni V, Pigozzo J, Fabozzi A, Tropea S, Vecchiato A, Costa A, Parisi A, Rossi CR, Del Fiore P, Alaibac M (September 2018). “Prognostic Factors in Merkel Cell Carcinoma: A Retrospective Single-Center Study in 90 Patients”. Cancers (Basel). 10 (10). doi:10.3390/cancers10100350. PMC 6210570. PMID 30249978.

Overview