Objective To summarize the current advancement of preoperative radiotherapy for rectal cancer. Methods Relevant literatures about current advancement of preoperative radiotherapy for rectal cancer published domesticly and abroad recently were collected and reviewed. Results The lower local recurrence rate and longer disease-free survival time were observed in preoperative radiotherapy， compared with postoperative radiotherapy for rectal cancer. The recurrence rate was higher in short-course radiotherapy， compared with conventionally radiotherapy for stageⅢrectal cancer， but there was no significant difference for stageⅡrectal cancer. The biology molecular such as p53， CEA， Cox-2， EGFR， and VEGF had shown to be radiosensitive. Conclusions The proposal of preoperative radiotherapy for rectal cancer， could be prone to conventionally radiotherapy. There are more screening targets for preoperative radiotherapy in extensive exploration of diverse radiosensitivity. Biology molecular， developed gene expression profiling， and gene chips for rectal cancer may contribute to the individualization treatment.
ObjectiveTo evaluate the possible role of the expression of insulin-like growth factor-1 receptor (IGF-1R) in determining rectal cancer radiosensitivity. MethodsThe paired preradiation biopsy specimens and postoperative specimens were obtained from 87 patients with rectal cancer in the department of digestive tumor surgery, Jiangsu Province Hospital of Traditional Chinese Medicine, Affiliated Hospital of Nanjing University of Traditional Chinese Medicine from January 2009 to December 2010. The IGF-1R expression was examined by immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). The tumor radiosensitivity was defined according to Rectal Cancer Regression Grade, then the relation between the IGF-1R expression and tumor radiosensitivity was evaluated. ResultsCompared with the preradiation biopsy specimens, IGF-1R expression significantly increased in the paired postoperative specimens of the residual cancer cells (Plt;0.001). The IHC result demonstrated IGF-1R overexpression was significantly associated with a poor response to radiotherapy (rs=0.401, Plt;0.001); RT-PCR detection of IGF-1R expression on preradiation biopsy specimens also showed that IGF-1R mRNA negative patients had a higher radiation sensitivity (rs=0.497, Plt;0.001). ConclusionDetection of IGF-1R expression may predict radiosensitivity of preoperative irradiation for rectal cancer.