Merkel Cell Carcinoma: Population-Based Study Focuses on Predictors of Relapse
Posted: Thursday, January 6, 2022
Kurian Joseph, MD, of the University of Alberta & Cross Cancer Institute, Edmonton, Canada, and colleagues evaluated the patterns and predictors of relapse in patients with Merkel cell carcinoma by performing a population-based study. In Radiotherapy & Oncology, the study authors reported that adjuvant radiotherapy improved recurrence-free survival without impacting Merkel cell carcinoma–specific survival and overall survival. They also noted that comorbidity appeared to be independently associated with overall survival.
“For stage I, adjuvant radiotherapy may be avoided in low-risk patients with negative sentinel lymph node biopsy and adequate margin clearance but is recommended for patients with high-risk factors such as positive margin, immunosuppression, and lymphovascular invasion,” the investigators concluded. “Although stage III patients benefited from adjuvant regional node irradiation, it did not improve systemic control.”
A total of 217 patients with a histologic diagnosis of Merkel cell carcinoma were included in this study. Extracted patient data included baseline demographics, tumor characteristics, treatment regimens, and follow-up information. Charlson Comorbidity index was also calculated for each participant to identify the correlation between survival outcome and comorbidities.
The median follow-up was 40 months. Surgery plus radiotherapy was the preferred treatment option among 55% of individuals, followed by surgery alone (45%). In patients with stage I disease (n = 6), the rate of local recurrence was low, with a clear margin of at least 1 cm and negative sentinel lymph node biopsy without high-risk factors, regardless of adjuvant radiotherapy.
According to the study authors, a high risk of nodal failure was significantly associated with immunosuppression (P = .001) and a tumor size greater than 2 cm (P = .024), whereas adjuvant radiotherapy seemed to be correlated with a significant reduction in regional failure (P = .002). Additionally, distant metastases appeared to be infrequent in patients with stage I (n = 4) and II (n = 4) disease compared with those who had stage III disease (n = 32).
Disclosure: The study authors reported no conflicts of interest.