A phase I/II study on stereotactic body radiotherapy with real-time tumor tracking using CyberKnife based on the Monte Carlo algorithm for lung tumors

• Published in: International journal of clinical oncology Vol. 22; no. 4; pp. 706 - 714
• Main Authors: Iwata, Hiromitsu, Ishikura, Satoshi, Murai, Taro, Iwabuchi, Michio, Inoue, Mitsuhiro, Tatewaki, Koshi, Ohta, Seiji, Yokota, Naoki, Shibamoto, Yuta
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.08.2017; Springer Nature B.V
• Subjects: Aged; Aged, 80 and over; Algorithms; Cancer Research; Carcinoma, Non-Small-Cell Lung - mortality; Carcinoma, Non-Small-Cell Lung - pathology; Carcinoma, Non-Small-Cell Lung - radiotherapy; Female; Humans; Lung cancer; Lung Neoplasms - mortality; Lung Neoplasms - pathology; Lung Neoplasms - radiotherapy; Male; Medicine; Medicine & Public Health; Metastases; Metastasis; Middle Aged; Monte Carlo Method; Monte Carlo simulation; Oncology; Original Article; Pneumonitis; Quality assurance; Radiation therapy; Radiosurgery - adverse effects; Radiosurgery - instrumentation; Radiosurgery - methods; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Surgical Oncology; Survival; Treatment Outcome; Tumors; Stereotactic body radiotherapy; CyberKnife; Phase I/II study; Tracking; Monte Carlo algorithm; Lung tumors
• ISSN: 1341-9625; 1437-7772; 1437-7772
• DOI: 10.1007/s10147-017-1123-0

Background In this phase I/II study, we assessed the safety and initial efficacy of stereotactic body radiotherapy (SBRT) for lung tumors with real-time tumor tracking using CyberKnife based on the Monte Carlo algorithm. Methods Study subjects had histologically confirmed primary non-small-cell lung cancer staged as T1a-T2aN0M0 and pulmonary oligometastasis. The primary endpoint was the incidence of Grade ≥3 radiation pneumonitis (RP) within 180 days of the start of SBRT. The secondary endpoint was local control and overall survival rates. Five patients were initially enrolled at level 1 [50 Gy/4 fractions (Fr)]; during the observation period, level 0 (45 Gy/4 Fr) was opened. The dose was escalated to the next level when grade ≥3 RP was observed in 0 out of 5 or 1 out of 10 patients. Virtual quality assurance planning was performed for 60 Gy/4 Fr; however, dose constraints for the organs at risk did not appear to be within acceptable ranges. Therefore, level 2 (55 Gy/4 Fr) was regarded as the upper limit. After the recommended dose (RD) was established, 15 additional patients were enrolled at the RD. The prescribed dose was normalized at the 95% volume border of the planning target volume based on the Monte Carlo algorithm. Results Between September 2011 and September 2015, 40 patients (primary 30; metastasis 10) were enrolled. Five patients were enrolled at level 0, 15 at level 1, and 20 at level 2. Only one grade 3 RP was observed at level 1. Two-year local control and overall survival rates were 98 and 81%, respectively. Conclusion The RD was 55 Gy/4 Fr. SBRT with real-time tumor tracking using CyberKnife based on the Monte Carlo algorithm was tolerated well and appeared to be effective for solitary lung tumors.