A randomized controlled trial comparing the efficacy and toxicities between neoadjuvant concomitant boost intensity-modulated radiotherapy (IMRT) and 3-dimensional conformal radiotherapy (3-DCRT) for locally advanced rectal cancer / 中华放射医学与防护杂志

ABSTRACT

Objective To compare the efficacy and toxicities between preoperative concomitant boost intensity-modulated radiotherapy (IMRT) and 3-dimensional conformal RT (3-DCRT) for locally advanced rectal cancer.Methods A prospective study from May 2010 to May 2015.A total of 130 patients with histologically confirmed,newly diagnosed,locally advanced rectal adenocarcinoma (cT3-T4 and/or cN +) located within 10 cm from the anal verge were included in this study.The patients were divided into IMRT and 3D-CRT groups by random number table method.Sixty-six patients were treated with IMRT,and the other sixty-four patients were treated with 3-DCRT.In the IMRT group,the prescription dose was 1.8 Gy/fraction to 45 Gy to the pelvis and 2.2 Gy/fraction to 55 Gy to the gross tumor volume simultaneously.The 3D-CRT prescription was 45 Gy in 25 fractions to the pelvis.Capecitabine (1 650 mg· m 2 · d-1) was given twice daily from days 1 to 14 and days 22 to 35 during RT in both arms.Total mesorectal excision (TME) was scheduled 6-8 weeks after the completion of chemoradiation.Results There were no significant differences in age,gender,tumor location,pathological differentiation degree and clinical stage between the two groups.Two patients withdrew from the study:one for grade 3 radiation dermatitis in IMRT group and the other for grade 3 fatigue in 3D-CRT.There was no significant difference in hematologic or nonhematologic toxicities between the two groups.No grade 4 or 5 toxicity was observed in either group.Compared with conformal radiotherapy,IMRT did not increase the difficulty of surgery.No significant difference was found in type of surgery or postoperative complications between the two groups.The rate of tumor regression grade (TRG) 4 (pathologic complete response,pCR) was 22.7％ for IMRT and 15.6％ for 3D-CRT,respectively(P ＞ 0.05).The rate of both TRG4 and 3 was 42.4％ for IMRT and 25.0％ for 3D-CRT,respectively (x2 =4.406,P=0.036).Conclusions Neoadjuvant concomitant boost IMRT is feasible and has a higher histopathological regression for patients with locally advanced rectal cancer.Trial registration Chinese clinical trial registry,ChiCTR-IN R-16008004.