Efficacy of preoperative neoadjuvant simultaneous integrated boost intensity-modulated radiotherapy combined with preoperative chemotherapy for locally advanced rectal cancer: a phase II clinical study

Abstract

Objective To investigate the feasibility, safety, and short-term efficacy of preoperative capecitabine and simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) followed by one cycle of neoadjuvant capecitabine in patients with locally advanced rectal cancer (LARC). Methods From March 2015 to April 2016, a total of 37 patients with LARC were enrolled in this study. They received capecitabine (825 mg/m2 orally twice daily for 5 weeks, days 1-5 weekly) and SIB-IMRT (58.75 Gy in 25 fractions for rectal lesion and positive lymph nodes and 50.00 Gy in 25 fractions for pelvic lymphatic drainage area). After the concurrent chemoradiotherapy, they were allowed to rest for one week. And then they received one cycle of induction chemotherapy with capecitabine (1250 mg/m2 orally twice daily for 14 days). And total mesorectal excision (TME) was scheduled at 6-8 weeks after the concurrent chemoradiotherapy. The primary endpoint was pathologic complete response (pCR) rate, and the secondary endpoints included tumor and nodal (TN) downstaging rate, the rate of sphincter-preserving surgery, and adverse events. Results All the 37 patients successfully received the preoperative concurrent chemoradiotherapy. Only 32 patients underwent the surgical resection, 4 patients refused surgery due to symptom relief, and 1 patient delayed surgery due to perianal edema after radiotherapy. The pCR rate was 34%(11/32); the TN downstaging rate was 91%(29/32); the R0 resection rate was 100%; 24 patients (75%) underwent the sphincter-preserving surgery. During the period of chemoradiotherapy, most of the patients experienced grade 1/2 acute adverse events and grade 3/4 adverse events occurred in 3 patients. The postoperative complications included ureteral injury (1 patient) and intestinal obstruction (1 patient), and no death occurred in the perioperative period. Conclusions For patients with LARC, preoperative SIB-IMRT combined with one cycle of capecitabine followed by TME is safe and feasible, and has good short-term efficacy and mild acute adverse events. Key words: Rectal neoplasms/intensity modulated radiotherapy; Intensity modulated radiotherapy, boost; Rectal neoplasms/chemotherapy; Capecitabine