Link Between Primary Location of Merkel Cell Carcinoma and Sites of Distant Metastases
Posted: Monday, February 10, 2020
A retrospective analysis published in Cancer Medicine investigated the relationship between primary lesion and metastatic sites of Merkel cell carcinoma. The study, conducted by Paul Nghiem, MD PhD, of the University of Washington, Seattle, and colleagues, examined how the likelihood of survival may change based on the site of metastasis and whether the site of the primary lesion can predict the initial metastatic site.
The study enrolled 215 patients with metastatic Merkel cell carcinoma. Distant metastasis occurred in 49% of patients within the first year and increased to 80% of patients in the second year. Metastatic sites included lymph nodes, distant skin/body wall, liver, bone, pancreas, brain, adrenal gland, bowel, peritoneum/retroperitoneum, gonad, oral, heart, kidneys, spleen, and urinary bladder. The most frequent sites of metastasis included lymph nodes (41%), skin/body wall (25%), liver (23%), and bone (21%).
After identifying the sites of metastasis, the authors explored the relationship between primary lesion site and metastatic site, finding differential correlations based on the primary lesion site. For instance, patients with a head/neck primary lesion were at a higher risk of developing a liver metastasis compared with other sites (43.1% vs. 15.3% P < .001). Also, patients who were diagnosed with primary Merkel cell carcinoma of the lower limb were at higher risk to develop distant nodal metastasis than patients with other primary lesions (56.4% vs. 37.5% P < .033).
During follow-up, 75% of patients died. Survival rates after diagnosis of metastases were 45% at 1 year, 22% at 3 years, and 18% at 5 years. The authors searched for a relationship between prognosis based on metastasis from the primary site. They found that patients with multiple metastatic sites, liver metastases, and nodal metastasis all had a worse prognosis than those with skin/body wall metastases. The authors noted that the results of this study could be useful in increasing the accuracy of prognosis and providing stricter guidelines for surveillance of Merkel cell carcinoma.
Disclosure: For full disclosures of the study authors, visit onlinelibrary.wiley.com.