A preliminary experience of moderate-intensity stereotactic body radiation therapy for ultra-central lung tumor

Abstract

Purpose: Administration of stereotactic body radiation therapy (SBRT) to ultra-central (UC) lung tumors, generally defined as those abutting the proximal bronchial trees, is difficult due to concerns about serious toxicities. Therefore, our institution has performed moderate-intensity SBRT.

Patients and methods: Patients with UC tumors underwent SBRT at a dose of 50–60 Gy in 10 fractions, with D_max in the target volume not exceeding 110% of the prescribed dose. The primary outcomes were tumor response and overall survival (OS).

Results: From January 2017 to September 2018, we treated eight patients who had been diagnosed with UC tumors. The median follow-up time was 8.6 months (range: 2.7–14.9). Five of the eight patients (62.5%) showed a complete response (CR), two (25%) had a partial response (PR), and one (12.5%) had stable disease (SD); the response and disease control rates were 87.5% and 100%, respectively. Seven patients were alive with no evidence of disease or with controlled disease until the last follow-ups, except for one patient who died due to a non-RT cause at 3 months after SBRT. One patient experienced grade 2 esophageal pain and another had grade 1 cough. No grade 3 or higher toxicities were reported.

Conclusion: Moderate-intensity SBRT might aid in achieving good control of UC tumors without excessive toxicities. Future studies involving larger numbers of patients and longer follow-up times are warranted to confirm the efficacy and feasibility.

Keywords:

• Stereotactic body radiotherapy
• ultra-central tumor
• feasibility
• radiotherapy

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethical approval

Our study is evaluated and approved by institutional review board of Korea University Medical Center (IRB number: 2018AS0175), and informed consent was waived because our study did not have any harm for patients involved and no personally identifiable information were used.

Additional information

Funding

This study was supported by the National Research Fund of Korea under grant NRF-2019M2D2A1A01031560.

Notes on contributors

Sunmin Park

Sunmin Park, Sunmin Park is a certified radiation oncologist, trained and achieved doctoral degree at Asan Medical Center of Korea, which is the largest hospital in the East Asia.

Young Kim

Young Kim, Young Kim is an experienced physician in pulmonary division of internal medicine. She primarily has taken care of patients included in the present study, referred them to the radiation oncology department, and discussed the ultimate clinical decision with Chai Hong Rim. She shared her expertise in pulmonology for this study.

Won Sup Yoon

Won Sup Yoon, Won Sup Yoon is a head of radiation oncology department at Korea University Ansan Hospital. He published a number of studies regarding radiotherapy for breast cancer, liver cancer, and also dosimetry of radiotherapy. He supervised and inspired the study, and participated in actual treatments of patients included in the present study.

Chai Hong Rim

Chai Hong Rim, Chai Hong Rim has been in charge of radiotherapy for the patients included in the study. He performed most of drafting and statistical analyses. He has his expertise not only in the clinical radiotherapy, but also the meta-analysis of clinical series with publishing more than 6 meta-analysis articles in recent 2 years.