ASCO 2021: Dutch Study of Postoperative Radiotherapy in Merkel Cell Carcinoma
Posted: Friday, June 25, 2021
Sonja Levy, MD, of the Netherlands Cancer Institute, Amsterdam, and colleagues conducted a study evaluating the impact of postoperative radiotherapy on the survival of patients with stage I to III Merkel cell carcinoma. During the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting, the investigators reported that although postoperative radiotherapy did not demonstrate a benefit in disease-specific survival, there was an observed improvement in recurrence-free survival for those with stage III disease (Abstract 9575).
In this retrospective study, the researchers focused on 219 patients from the Netherlands who had pathologic stage I/II (n = 54), clinical stage I/II (n = 82), and stage III (n = 83) Merkel cell carcinoma. They also all underwent postoperative radiotherapy.
The median time to follow-up was 53.4 months, 28 months, and 30.8 months for patients with pathologic stage I/II, clinical stage I/II, and stage III Merkel cell carcinoma, respectively. No confounding was identified by propensity score matching. In patients with pathologic and clinical stage I/II disease, most recurrences were regional, but a majority of patients with stage III disease had distant recurrence.
Across all stages of disease, recurrence-free survival significantly differed (P < .001); disease-specific survival was significantly worse for patients with clinical stage I/II and stage III Merkel cell carcinoma compared with those who had pathologic stage I/II disease (P = .003). Notably, the authors reported that postoperative radiotherapy did not seem to improve survival for the majority of patients.
According to a multivariable analysis, predictors for disease-specific survival included male gender (hazard ratio [HR] = 1.94, P = .030), performance status of 3 (HR = 3.87, P = .014) and an unknown performance status (HR = 5.45, P = .004), primary tumor on the trunk (HR = 2.67, P = .008), clinical stage I/II disease (HR = 5.38, P = .001), and stage III disease (HR = 6.44, P < .001).
Disclosure: Dr. Levy reported no conflicts of interest. For full disclosures of the other study authors, visit coi.asco.org.
