Preoperative three dimensional conformal radiotherapy and volumetric modulated arc therapy concurrently combined with chemotherapy for locally advanced rectum cancer: a five-year follow-up study / 中华放射肿瘤学杂志

ABSTRACT

Objective:To compare 5-year overall survival (OS) and disease free survival (DFS) between preoperative three dimensional conformal radiotherapy (3DCRT) and volumetric medulated arc therapy (VMAT) concurrently combined with chemotherapy for locally advanced rectum cancer (LARC), and analyze the value of induction and/or consolidation chemotherapy in these circumstances.Methods:334 patients with LARC treated with preoperative 3DCRT (172 cases) and VMAT (162 cases) concurrently combined with chemotherapy, main protocol XELOX (capecitabine plus oxaplatin), and subsequent surgery in Sun Yat-sen University from May 2007 to April 2013 were retrospectively analyzed. The radiation prescription dose for VMAT group was 50 Gy 25 fractions for planning target volume1(PTV 1), and 46 Gy 25 fractions for PTV 2. The radiation prescription dose for 3DCRT group was 46 Gy 23 fractions for PTV 2. One hundred and eighty-five cases of all received preoperative concurrent chemoradiotherapy (namely, CCRT group), 149 cases received preoperative concurrent chemoradiotherapy plus median 2 courses (1-7 courses) induction and/or consolidation chemotherapy (namely, CCRT±induction chemotherapy±consolidation chemotherapy group), whose main chemotherapy protocol was XELOX. Difference of 5-year OS and DFS between 3DCRT and VMAT group was compared. The rate differences of acute toxicity during chemoradiotherapy, postoperative complications, ypCR, and survival between CCRT group and CCRT±induction chemotherapy±consolidation chemotherapy group were analyzed. Results:After a median follow-up of 62.3 months (2.4-119months) for the 334 patients, no any significant difference for 5-year OS (79.0% vs. 83.2%, P=0.442) and 5-year DFS (77.0% vs. 82.1%, P=0.231) between 3DCRT and VMAT group was observed. There was no any significant difference for the Grade 3 hematological toxicity (7.0% vs. 12.1%, P=0.114) and non-hematological toxicity (14.1% vs. 16.8%, P=0.491) during chemoradiotherapy, postoperative complications (17.3% vs. 17.4%, P=0.971), ypCR rate (25.4% vs. 30.2%, P=0.329), 5-year OS (80.5% vs. 82.0%, P=0.714) and 5-year DFS (78.8% vs. 81%, P=0.479) between CCRT group and CCRT±induction chemotherapy±consolidation chemotherapy group. Conclusions:Compared with 3DCRT, the physics advantage of VMAT technique does not significantly convert into clinical benefits and improve 5-year OS and DFS, even further boosting radiation dose to the gross tumor volume. It is safe for median 2 courses of induction and/or consolidation chemotherapy before and or after preoperative concurrent chemoradiotherapy in the treatment of LARC, though it does not significantly improve ypCR rate and survival.