Patterns of initial distant metastases in 151 patients undergoing surveillance for treated Merkel cell carcinoma

March 17, 2024


Journal of the European Academy of Dermatology

Publication Date

March 17, 2024


Kim E, Liu M, Giobbie-Hurder A, Bahar F, Khaddour K, Silk A, Thakuria M Summary

MCC is a cancer that has a high risk of coming back (recurrence) or spreading to other places. This study looked at how the location where the cancer first developed is related to where it tends to come back. The findings from this study supported the results of a similar paper from 2020. Both studies found that MCC originally on the head or neck is more likely to come back in the liver, whereas MCC originally on the legs is more likely to come back in the distant lymph nodes. These studies can give doctors a better idea of which patients may be at greater risk for MCC recurring in certain places, although recent progress such as surveillance blood tests and immunotherapy have greatly improved survival in patients with recurrent MCC.



Merkel cell carcinoma (MCC) is associated with high rates of recurrence and distant metastatic progression. Current guidelines for surveillance imaging are not evidence based. Better characterization of the pattern of distant metastatic spread will better inform surveillance and facilitate earlier detection of metastases.


This retrospective study aimed to assess potential relationships between primary tumour site and site of initial distant metastasis, time to distant metastasis, overall survival (OS) and MCC-specific death (MSD).


Patients with local or regional (Stage I–III) disease who were treated with curative intent and progressed to Stage IV were included in this study (n = 151). Fisher’s exact test was used to assess differences in patterns of initial distant metastases based on primary tumour site. Time to initial distant metastasis was calculated from date of MCC diagnosis. OS and MSD were calculated from date of initial distant metastasis to date of death from any or MCC-related causes, respectively.


Of 151 patients included in analysis, 89 (58.9%) had a single initial distant metastatic site, and 62 (41.1%) had multiple sites. Patients with upper limb primary tumours were significantly less likely to develop distant lymph node or liver metastases (p = 0.02 and 0.04, respectively). Median time to distant metastasis was 11 months (IQR 6.7–17.9 months). Median OS was 15.3 months, and was shorter for patients with liver (7.0 months, p = 0.0004) or bone metastases (8.9 months, p < 0.0001). Using skin/soft tissue metastasis as a reference group, patients with multiple metastatic sites had significantly higher hazards of MSD (HR = 3.46 univariate, 3.77 multivariate analysis). Time to distant metastasis, OS and MSD did not differ by viral status.


Sites of initial distant metastasis are related to primary tumour sites and survival outcomes. Because patients often have multiple initial metastases, full-body cross-sectional rather than region-specific imaging may facilitate earlier detection of metastatic disease.

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