Clinical Study Of Preperative Chemoradiation With A Simultaneous Integrated Boost For Rectal Cancer

Purpose :This prospective trial compared simultaneous integrated boost intensity-modulated radiation therapy(SIB-IMRT)versus Regular-IMRT(R-IMRT)in the preoperative concurrent chemoradiotherapy of locally advanced rectal carcinoma.Patients and Methods:Patients with locally advanced rectal cancer were randomly assigned to SIB-IMRT or R-IMRT chemoradiotherapy,patients received 56 Gy in 25 fractions(2.24 Gy/fraction)for margins and gross tumor and metastatic-lymph nodes and 50 Gy in 25 fractions for pelvic lymphatic drainage area in the SIB-IMRT group,and pelvic radiation therapy 50 Gy at 2.0Gy per day in the R-IMRT group,all the patients took capecitabine(825 mg/m2 po bid,q1-q14,with a week interval and then keep on to the end of treatment)simultaneously.Surgery was performed after 6 to 8 weeks interval follow on the completion of neoadjuvant therapy.Results:A total of 55 patients were entered onto the study,with 52(94.5%)assessable for response.For 52 patients,between SIB-IMRT group and R-IMRT group,the T tumor downstaging rates were 83.3% vs.53.6%(p=0.023);N tumor downstaging rates were observed in 91.7% vs.64.3%(p=0.019),The tumor regress grade 0(TRG0 :completepathologicresponse)were 26.3% vs.16.7%(p=0.440).Sphincter-saving rates were 73.7%vs.79.2%(p=0.953);toxicity rates were 14.3% vs 10.7%(p=0.698),no grade 3/4hematological toxicological reactions were observed in both groups.Conclusions: Compared with R-IMRT,the preoperative chemoradiotherapy pattern of SIB-IMRT with capecitabine was well tolerated for patients with locally advanced rectal cancer,the short term outcomes were promising.