Final report of a prospective randomized study on thoracic radiotherapy target volume for limited‐stage small cell lung cancer with radiation dosimetric analyses. Issue 4 (12th November 2019)

• Record Type: Journal Article
• Authors: Hu, Xiao; Bao, Yong; Xu, Yu‐jin; Zhu, Hui‐neng; Liu, Jin‐shi; Zhang, Li; Guo, Ying; Jin, Ying; Wang, Jin; Ma, Hong‐lian; Xu, Xiao‐ling; Song, Zheng‐bo; Tang, Hua‐rong; Peng, Fang; Fang, Min; Kong, Yue; Chen, Meng‐yuan; Dong, Bai‐qiang; Zhu, Liang; Yu, Chang; Yu, Xin‐min; Hong, Wei; Fan, Yun; Zhang, Yi‐ping; Chen, Peng‐cheng; Zhao, Qiang; Jiang, You‐hua; Zhou, Xin‐ming; Chen, Qi‐xun; Sun, Wen‐yong; Mao, Wei‐min; Chen, Ming;
• Is Part Of: Cancer. Volume 126:Issue 4(2020)
• Page Start: 840
• Page End: 849
• Publication Date: 2019-11-12
• Subjects: combined modality treatment -- limited‐stage -- lung cancer -- radiation target volume small cell; Cancer -- Periodicals; Cancer -- Cytopathology -- Periodicals; 616.99405
• DOI: 10.1002/cncr.32586
• Languages: English
• ISSNs: 0008-543X

Abstract

Abstract : Background: The thoracic radiotherapy (TRT) target volume for limited‐stage small‐cell lung cancer (SCLC) has been controversial for decades. In this report, the final results of a prospective randomized trial on the TRT target volume before and after induction chemotherapy are presented. Methods: After 2 cycles of etoposide and cisplatin, patients arm were randomized to receive TRT to the postchemotherapy or prechemotherapy tumor volume in a study arm and a control arm. Involved‐field radiotherapy was received in both arms. TRT consisted of 1.5 grays (Gy) twice daily in 30 fractions to up to a total dose of 45 Gy. Lymph node regions were contoured, and intentional and incidental radiation doses were recorded. Results: The study was halted early because of slow accrual. Between 2002 and 2017, 159 and 150 patients were randomized to the study arm or the control arm, respectively; and 21.4% and 19.1% of patients, respectively, were staged using positron emission tomography/computed tomography ( P = .31). With a median follow‐up of 54.1 months (range, 19.9‐165.0 months) in survivors, the 3‐year local/regional progression‐free probability was 58.2% and 65.5% in the study and control arms, respectively ( P = .44), and the absolute difference was −7.3% (95% CI, −18.2%, 3.7%). In the study and control arms, the median overall survival was 21.9 months and 26.6 months, respectively, and the 5‐year overall survival rate was 22.8% and 28.1%, respectively ( P = .26). Grade 3 esophagitis was observed in 5.9% of patients in the study arm versus 15.5% of those in the control arm ( P = .01). The isolated out‐of‐field failure rate was 2.6% in the study arm versus 4.1% in the control arm ( P = .46), and all such failures were located in the supraclavicular fossa or contralateral hilum. The regions 7, 3P, 4L, 6, 4R, 5, and 2L received incidental radiation doses >30 Gy. Conclusions: TRT could be limited to the postchemotherapy tumor volume, and involved‐field radiotherapy could be routinely applied for limited‐stage SCLC. Abstract : This is the only phase 3 study on thoracic radiotherapy target volumes for limited‐stage small‐cell lung cancer using modern radiotherapy facilities. Radiation dosimetric and pathologic analyses are also performed to interpret the clinical findings.