Role of Sentinel Lymph Node Biopsy Status in Adjuvant Radiotherapy for Merkel Cell Carcinoma
Posted: Tuesday, October 5, 2021
Sue S. Yom, MD, PhD, MAS, of the University of California San Francisco, and colleagues investigated whether the sentinel lymph node biopsy (SLNB) status of patients with Merkel cell carcinoma could help determine the extent of radiotherapy necessary to achieve disease control. Published in Advances in Radiation Oncology, their findings demonstrated that there was, in fact, a correlation between improved survival rates and SLNB status–based radiotherapy regimens.
From 1996 to 2015, a total of 57 patients with node-negative Merkel cell carcinoma who underwent wide local excision and SLNB were identified for the study. A total of 33 SLNB-negative patients were given adjuvant radiotherapy to the primary site, whereas 9 patients were observed. Of the SLNB-positive patients, 13 were treated with radiotherapy to the primary site plus nodal basin, whereas 2 were observed.
The study findings revealed significant differences between SLNB-negative patients given radiotherapy to the primary site and SLNB-positive patients given comprehensive radiotherapy. Node-negative patients had a 4-year disease-specific survival of 100% (P = .008) and a local recurrence-free survival of 100% (P = .008), whereas the node-positive patients had a 4-year disease-specific survival and a recurrence-free survival of 65% and 75%, respectively. Overall survival rates did not seem to differ significantly, at 87.5% and 57.7% (P = .164), respectively. Moreover, 67% of observed node-negative patients had any disease failure, whereas 50% of observed node-positive patients had a distant relapse.
“Radiotherapy to the primary site was important for optimizing local control. Regional radiotherapy may not be necessary in cases of negative sentinel lymph node biopsy, which demonstrated a low risk of relapse in the nodal bed,” wrote the authors.
Disclosure: For full disclosures of the study authors, visit www.advancesradonc.org.