Original article
Relationships among primary tumor size, number of involved nodes, and survival for 8044 cases of Merkel cell carcinoma

https://doi.org/10.1016/j.jaad.2013.11.031Get rights and content

Background

The effects of primary tumor size on nodal involvement and of number of involved nodes on survival have not, to our knowledge, been examined in a national database of Merkel cell carcinoma (MCC).

Objective

We sought to analyze a retrospective cohort of patients with MCC from the largest US national database to assess the relationships between these clinical parameters and survival.

Methods

A total of 8044 MCC cases in the National Cancer Data Base were analyzed.

Results

There was a 14% risk of regional nodal involvement for 0.5-cm tumors that increased to 25% for 1.7-cm (median-sized) tumors and to more than 36% for tumors 6 cm or larger. The number of involved nodes was strongly predictive of survival (0 nodes, 76% 5-year relative survival; 1 node, 50%; 2 nodes, 47%; 3-5 nodes, 42%; and ≥6 nodes, 24%; P < .0001 for trend). Younger and/or male patients were more likely to undergo pathological nodal evaluation.

Limitations

The National Cancer Data Base does not capture disease-specific survival. Hence, relative survival was calculated by comparing overall survival with age- and sex-matched US population data.

Conclusion

Pathologic nodal evaluation should be considered even for patients with small primary MCC tumors. The number of involved nodes is strongly predictive of survival and may help improve prognostic accuracy and management.

Section snippets

Methods

All studies were performed in accordance with Helsinki principles and institutionally approved (institutional review board approval No. 6585). A total of 10,020 cases diagnosed between January 1, 1985, and December 31, 2004, were identified from the NCDB using MCC-specific histology code 8247. In all, 1684 cases missing all TNM information and 292 distant metastatic cases that lacked tumor size information were not included, resulting in a cohort of 8044 cases.

All cases with primary tumor

Results

The demographic characteristics of 8044 patients with MCC given a diagnosis between 1985 and 2004 are presented in Table I. The NCDB had primary tumor size information on 5722 cases (71.1%) and no tumor size information on 1976 cases. The NCDB collects follow-up data from the time of initial diagnosis at 5-year intervals. Follow-up data were available for 4542 of the 8044 cases. Among 1830 live patients, median follow-up was 64.2 months (range 0.5-198 months).

The distribution of MCC primary

Discussion

This study examined 8044 cases from the NCDB to determine the relationship of MCC regional nodal involvement with primary tumor size and the relationship of number of involved nodes with survival. Our findings indicate that patients with small primary MCC tumors have significant risk of nodal disease at the time of presentation and that the number of involved nodes is strongly predictive of survival.

Prior studies of primary tumor size (27-153 cases) reported a median size of 1.2 cm or 1.9 cm.3,

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    • Cited by (0)

    Supported by National Institutes of Health (NIH) K02-AR50993, American Cancer Society RSG-08-115-01-CCE, NIH K24-CA139052, the David and Rosalind Bloom Endowment for Merkel Cell Carcinoma Research, the Michael Piepkorn Endowment, and the University of Washington Merkel Cell Carcinoma Patient Gift Fund.

    Conflicts of interest: None declared.

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    Copyright © 2013 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.