A comparative study of distribution of residual cancer cells in the bowel wall after preoperative three-dimensional conformal radiotherapy versus volumetric modulated arc therapy with concurrent chemotherapy in treatment of locally advanced rectum cancer
Department of Radiation Oncology,Sun Yat-sen University Cancer Center,State Key Laboratory of Oncology in South China,Guangzhou 510060,China;Department of Oncology,Section Ⅱ,Jiangmen Central Hospital,Affiliated Jiangmen Hospital of Sun Yat-sen University,Jiangmen 529030,China (Xiao L)
Abstract：Objective To compare the distribution of residual cancer cells (RCC) in each layer of bowl wall after preoperative three-dimensional conformal radiotherapy (3DCRT) versus volumetric modulated arc therapy (VMAT) combined with concurrent chemotherapy,and to investigate the effect of different radiotherapy techniques on the distribution of RCC. Methods A total of 334 patients with locally advanced rectum cancer (LARC) who were admitted to our hospital from May 2007 to April 2013 were enrolled as subjects. In those patients,172 received preoperative 3DCRT (46 Gy/23 F) with concurrent chemotherapy and 162 received VMAT (50 Gy/25 F) with concurrent chemotherapy. There was no significant difference in the distribution of clinical stage Ⅱ or Ⅲ between the 3DCRT group and VMAT group. All the RCCs in different layers of surgical specimens were evaluated pathologically. Between-group comparison of data was made by Pearson Chi-Square and Fisher′s exact test. Results There were no significant differences in ypT,ypN,or ypTNM staging between the two groups (P values>0.05).In the 226 patients with ypT2-4 disease,the proportion of RCC in the mucosa,submucosa,muscularis propria,and subserosa/perirectal fat was 34.1%,43.8%,73.5%,and 69.0%,respectively. In patients with ypT2-4,pN+,cN+,or cT4 disease,compared with the VMAT group,the 3DCRT group had significantly higher proportion of RCCs in the mucosa (47.9% vs. 18.1%,54.5% vs. 17.2%,39.8% vs. 15.3%,41.3% vs. 14.3%;P=0.000,0.001,0.000,0.000) and submucosa (50.4% vs. 36.2%,56.8% vs. 27.6%,43.0% vs.26.6%,45.3% vs. 27.5%;P=0.032,0.014,0.006,0.017).In patients with pN0 or cT3 disease,the 3DCRT group had a significantly higher proportion of RCCs in the mucosa than the VMAT group (28.1% vs. 12.9%,P=0.002;29.5% vs. 13.2%, P=0.015).In patients with ypT2-4,pN0/pN+,cT3/cT4,or cN0/cN+ disease,there were no significant differences in the proportion of RCCs in the muscularis propria or subserosa/perirectal fat between the two groups (P values>0.05). Conclusions After neoadjuvant chemoradiotherapy,most RCCs reside in the muscularis propria and subserosa/perirectal fat of the bowl wall. There are no significant differences in the distribution of most RCCs in the bowel wall or postoperative pathological staging between patients undergoing different radiotherapy techniques.
Xiao Lin,Zhu Yujia,Qiu Bo et al. A comparative study of distribution of residual cancer cells in the bowel wall after preoperative three-dimensional conformal radiotherapy versus volumetric modulated arc therapy with concurrent chemotherapy in treatment of locally advanced rectum cancer [J]. Chinese Journal of Radiation Oncology, 2016, 25(7): 708-712.
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2016, Vol. 25 
