Preliminary results of the prospective clinical trial of preoperative concomitant boost intensity-modulated radiotherapy in locally advanced rectal cancer

Objective To evaluate the feasibility,safety,and short-term efficacy of preoperative capecitabine and simultaneous integrated boost(SIB)intensity-modulated radiotherapy(IMRT)in patients with locally advanced rectal cancer.Methods Between August 2012 and May 2013,a total of 13 patients with resectable stage Ⅱ or Ⅲ rectal cancer received capecitabine(825 mg/m2 P.O,twice a day,5 d/week for 5 weeks)and SIB-IMRT delivering 56.25 Gy(2.25 Gy/fraction)to the gross tumor while simultaneously delivering 50 Gy(2.0 Gy/fraction)to the regional lymph nodes and areas at risk for harboring microscopic disease.Total mesorectal excision was scheduled 4 to 8 weeks after the completion of chemoradiation.The primary endpoints included pathological complete response rate(ypCR),tumor downstaging,toxicity and postoperative complications.The secondary endpoint included the rate of sphincter-sparing surgery.Results All patients completed chemoradiation with strict compliance to the protocol schedule and then went on to surgical resection.Three patients had no residual tumor in the surgical specimen.Downstaging of the primary tumor and lymph nodes was observed in 9 and 4 patients,respectively.Grade 1 or 2 toxicities included leucopenia,thrombocytopenia and diarrhea.One patient developed vesical fistula after surgery.Ten patients underwent sphincter-sparing procedures.Conclusions Preoperative chemoradiation with capecitabine and SIB-IMRT can be safe and well tolerated for patients with locally advanced rectal cancer and the short term outcomes could be promising. Key words: Rectal cancer; Intensity-modulated radiation therapy; Capecitabine