TOPLINE

Adjuvant radiation therapy (RT) use increased modestly among surgically treated patients with Merkel cell carcinoma (MCC) between 2000 and 2020, but rates did not increase for localized disease.

METHODOLOGY

• Researchers analyzed data of 8934 surgically treated patients with MCC from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2020.
• Adjuvant RT was defined as beam radiation delivered following surgery. Multivariable logistic regression models adjusted for year, age (< 50, 50-59, 60-69, 70-79, ≥ 80 years), race, sex, income quartile, urban residence, and disease stage (localized, regional, distant).
• A separate localized cohort model (n = 5030) also adjusted for tumor size, primary site, and nodal evaluation.
• Researchers assessed temporal trends in adjuvant RT use with year as a continuous predictor.

TAKEAWAY

• Overall adjuvant radiation therapy use increased from 40% during 2000-2005 to 47.6% during 2016-2020 (odds ratio [OR] per year, 1.02; P < .001), with the increase driven primarily by patients with regional disease. However, there was no significant temporal trend in localized disease.
• Compared with younger patients, those aged 80 years or older had lower odds of receiving RT (OR, 0.33; P < .001), whereas men (OR, 1.21; P < .001) and those with regional-stage disease (OR, 3.01; P < .001) were more likely to receive RT.
• Among patients with localized disease, tumors larger than 2 cm (OR, 1.76; P < .001), head and neck primary site (OR, 1.32; P < .001), and nodal evaluation (OR, 1.54; P < .001) independently predicted receipt of adjuvant RT. Only 40.1% of patients with a head and neck primary site received adjuvant RT.
• Of the 4868 patients who did not receive adjuvant RT, 2.9% had a recorded refusal, and 2.1% had RT recommended but whether it was ultimately given was unknown.

IN PRACTICE

"Adjuvant RT rates for localized MCC have not improved over two decades despite evidence supporting its use in reducing recurrence," the authors wrote. "Few patients refused RT, suggesting treatment variances are not driven by patient preferences," they added, noting that "variations in utilization may be driven by a range of factors from the specialty managing MCC patients, the rapidly evolving nature of NCCN [National Comprehensive Cancer Network] guidelines, and comorbidities preventing radiation."

SOURCE

The study was led by Ross O'Hagan, MD, Department of Dermatology, Icahn School of Medicine, Mount Sinai, New York, and was published online as a brief report on July 14 in the Journal of the American Academy of Dermatology.

LIMITATIONS

Limitations of the study include incomplete SEER data regarding patient comorbidities, immunosuppression status, and provider specialty. The SEER database incompletely captured immunotherapy use, which could have affected the interpretation of treatment trends for distant disease. The study period ended in 2020 and may not fully reflect more recent treatment patterns.

DISCLOSURES

The study did not receive any specific funding. The authors disclosed no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.