Radiation, Lymph Node Dissection, or Both: Management of Lymph Node Micrometastases from Merkel Cell Carcinoma

• Published in: Annals of surgical oncology 2023-07, Vol.30 (7), p.4345-4355
• Main Authors: Ma, Kevin L., Sharon, Cimarron E., Tortorello, Gabriella N., Perry, Nikhita J., Keele, Luke J., Lukens, John N., Karakousis, Giorgos C., Miura, John T.
• Format: Article
• Language: English
• Subjects: Aged; Carcinoma; Carcinoma, Merkel Cell - radiotherapy; Carcinoma, Merkel Cell - surgery; Female; Humans; Lymph Node Excision; Lymph nodes; Lymph Nodes - pathology; Lymph Nodes - surgery; Lymphatic system; Male; Medicine; Medicine & Public Health; Melanoma; Metastases; Multivariate analysis; Neoplasm Micrometastasis; Oncology; Radiation; Radiation therapy; Retrospective Studies; Sentinel Lymph Node Biopsy; Skin cancer; Skin Neoplasms - radiotherapy; Skin Neoplasms - surgery; Surgery; Surgical Oncology; Survival analysis
• ISSN: 1068-9265; 1534-4681
• DOI: 10.1245/s10434-023-13437-z

Background Regional lymph node micrometastases from Merkel cell carcinoma (MCC) can be treated with completion lymph node dissection (CLND) and/or radiation therapy (RT). It is unclear how these options compare in terms of survival benefits for patients. Patients and Methods This retrospective cohort study used data from years 2012–2019 of the National Cancer Database. Patients with MCC and clinically negative, but pathologically positive, lymph node metastases who received RT to and/or CLND of the regional lymph node basin were included. Inverse probability weight balancing was performed using covariates followed by Cox proportional hazards modeling for survival analysis. Results A total of 962 patients were included [median (interquartile range) age, 74 (67–80) years, 662 (68.8%) male patients, 926 (96.3%) white patients]. The majority (63%, n  = 606) had a CLND only, while 18% ( n  = 173) had RT only, and 19% ( n  = 183) had both CLND and RT. From 2016 to 2019, usage of RT only increased from 10% to 31.8%. Multivariate analysis demonstrated that treatment modality was not associated with survival [RT versus CLND, hazard ratio (HR) 0.842, 95% confidence interval (CI) 0.621–1.142, p  = 0.269, RT+CLND versus CLND, HR 1.029, 95% CI 0.775–1.367, p  = 0.844]. This persisted after balancing weights (RT versus CLND, HR 0.837, 95% CI 0.614–1.142, p  = 0.262, RT+CLND versus CLND, HR 1.085, 95% CI 0.801–1.470, p  = 0.599). Conclusions The usage of RT for nodal micrometastasis in MCC is increasing as compared with CLND. This strategy appears to be safe, with no significant difference in survival outcomes.