Clinical characteristics, risk factors, and outcomes after adjuvant radiotherapy for patients with thymoma in the United States: analysis of the Surveillance, Epidemiology, and End Results (SEER) Registry (1988–2013)

Abstract

Purpose: The surgery with adjuvant radiation for the treatment of thymoma is still debated. The aim of this study was to examine the efficacy of postoperative radiotherapy (PORT) in a population-based registry of patients with thymoma.

Materials and methods: We conducted a retrospective analysis of the Surveillance, Epidemiology, and End Results database to compare the outcomes of patients with thymoma who received surgery with or without PORT.

Results: Among the 2234 patients of this study, the surgery with PORT group had a longer mean overall survival (OS) and cancer-specific survival (CSS) than did the surgery without PORT group (OS: 172.3 vs. 155.3 months, p = .005; CSS: 247.3 vs. 241.8 months, p = .04). PORT significantly improved OS and CSS of patients with stage III/IV disease, but decreased CSS for those with stage I/IIA disease. Although the surgery with PORT group had a higher rate of secondary cancers, the between-group difference in the disease-free interval was not significant.

Conclusions: PORT provides a significant benefit for patients with thymoma, particularly those with advanced disease. However, it also increases the risk of a second malignancy. We suggest that treatment guidelines should adopt a more positive stance on the use of PORT.

Keywords:

• Adjuvant radiotherapy
• thymoma
• thymic epithelial tumors
• second primary malignancy
• SEER
• population-based

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Notes on contributors

Haibo Mou graduated from Zhejiang University School of Medicine. He is a chief physician and medical oncologist in the Department of Oncology, Zhejiang University International Hospital (Shulan Hospital), Hangzhou, China, with expertise in thoracic oncology, breast cancer, colorectal cancer and other malignant tumors. He has conducted and participated in many clinical trials in oncology.

Qin Liao graduated from Jiangxi Medical University. She is a fellow in the Department of Oncology, Zhejiang University International Hospital (Shulan Hospital), Hangzhou, China.

Xuehua Hou graduated from Zhejiang Chinese Medical University. She is an internal in the Department of Oncology, Zhejiang University International Hospital (Shulan Hospital), Hangzhou, China.

Te Chen graduated from Zhejiang University School of Medicine. He is an internal in the Department of Oncology, Zhejiang University International Hospital (Shulan Hospital), Hangzhou, China.

Yuping Zhu graduated from Zhejiang University School of Medicine. She is the nursing director of the Department of Oncology, Zhejiang University International Hospital (Shulan Hospital), Hangzhou, China.

Additional information

Funding

This study was supported by the Health Department of Zhejiang Province [2013KYB101], the Zhejiang Provincial Bureau of Traditional Chinese Medicine [2012ZB085] and the Project of Zhejiang Provincial Department of Education [Y201636437].