부산대학교 도서관

Object: Lung metastases from colorectal cancer are more radioresistant, requiring higher dose to obtain a stable local control. Here we evaluate two different techniques of stereotactic body radiotherapy (SBRT) for lung metastases from colorectal cancer in patients treated in our departmed. Material and methods: From 01/2006 to 07/2020, 69 lung metastases (37 patients) from colorectal cancer were treated with SBRT in our department: 48 lesions (27 patients) with 4DCT simulation and helical/VMAT IGIMRT (4DCT) and 21 lesions (10 patients) with real time-tracking robotic radiosurgery (CK). Median ages were 71.9 years (4DCT) vs 64.1 years (CK). Median GTV were 5.16 (0.31-88.6) cc (4DCT) vs 3.98 (0.16-16) cc (CK), while median PTV were 26.3 (6.3-180) (4DCT) cc vs 16.7 (1.9 vs 45.6) cc (CK), respectively. The tighter margins used with the real-time tracking was the main factor that determined a smaller PTV volume. Central lesions were 17.1% in the 4DCT group vs 23.5% in the CK group. Median BED precribed was 102.6 Gy in the 4DCT group vs 112.5 Gy in the CK group. The tighter margins allowed us not only to prescribe a higher median BED, but also to reduce the number of fractions and the overall treatment time from 2 weeks with 6 fractions every other day to 3 consecutive daily fractions. Results: Median follow-ups were 26.4 (3-85.7) months (4DCT group) vs 16.4 (3.4-37.4) months (CK group). The treatment was well tollerated: one patient presented a grade (G) 3 pneumonitis after a treatment on 6 lesions/4 PTV’s in one month with CK. Fully recovered she died one year later for distant metastases. Five patients presented G1/G2 cough and 1 with G1 dyspnea soon after the 4DCT treatment. Four patients had persistent G1 fibrosis, and 7 G1 dyspnea after the 4DCT treatment. Local control was of 69.3% (4DCT) vs 90.5% (CK) at 12 months, 46.5% vs 81.4% at 24 months (p= 0.08) (see Fig. 1). Overall survival at 12 months was 89.5% in the CK group vs 94.7% in the 4DCT group, at 24 months 64.6 % vs 76.5 %, and at 36 months 64.6% vs 51.7%, respectively. Conclusion: SBRT in lung oligometastases from colorectal cancer have a low toxicity profile. Even a small increase of BED from 102 Gy to 112 Gy, and the higher precision allowed by the real-time tracking shows a tendency towards better local control. [ABSTRACT FROM AUTHOR]