A Comparative Study Of Survival And Side Effects Between Preoperative And Postoperative Radiotherapy For Stage ?/? Rectal Cancer

Background and purpose:Colorectal cancer is a high-risk cancer in the clinic and it is a serious threat to human health.However,the pathogenesis of colorectal cancer has not been clearly elucidated.Current research shows that it is mainly related to many factors such as environment,diet,living habits,inflammatory stimuli,and genetic genes,and a combination of these factors.In the recent 10 years,the mortality and morbidity of colorectal cancer have increased with the above factors.Different from foreign countries,the incidence of rectal cancer in China is relatively high,accounting for 1/3 of the total number of colorectal cancer,the ratio of male to female is 1.3:1,and the risk of onset is significantly higher after 40 years old.Even though the treatment of rectal cancer relies mainly on surgery,with the deep research and development of oncology,currently the treatment plan that based on surgery,combined with radiotherapy,chemotherapy,and targeted therapy can effectively reduce local recurrence and distant metastasis of rectal cancer,and increase the long-term survival rate.Due to the relatively specific structure of the rectum,the early clinical manifestations of the patients are not significant,which makes the early tumors difficult to be detected.Most patients have locally advanced when being diagnosed,so that radical resection of rectal cancer has a large range of resection and high recurrence rate.Therefore,the diagnosis and treatment of locally advanced rectal cancer,that stage ?/? rectal cancer,often requires the cooperation of many related disciplines such as surgery,internal medicine,radiotherapy,imaging,and pathology.For the comprehensive treatment of locally advanced rectal cancer,the main research focuses on the TME(total mesorectal excision,total mesorectal excision)surgery and radiotherapy interval,radiotherapy segmentation and time model,chemotherapy and targeted drug selection and layout.Existing diagnostic guidelines show that the “sandwich cake” treatment model,which combined with preoperative concurrent chemoradiotherapy with TME and postoperative adjuvant chemotherapy,is the standard treatment for locally advanced rectal cancer.At present,this model has been widely promoted in some large hospitals in China.However,some clinical trials shows that this model can't improve the survival rate of rectal cancer significantly compared with postoperative concurrent chemoradiotherapy.Therefore traditional mode of postoperative concurrent chemoradiotherapy is still used in most hospitals.Both preoperative and postoperative radiotherapy are effective treatments for locally advanced rectal cancer at the present stage.However,whether preoperative radiotherapy and postoperative radiotherapy are superior or inferior,which method can improve the efficacy of radiotherapy,reduce and avoid the occurrence of adverse reactions,control recurrence and distant metastasis,retain effective organ function,reduce patient pain,reduce economic burden,this is still a fundamental problem faced by radiation oncologists in the treatment of rectal cancer.The purpose of this study was to retrospectively analyze patients undergoing preoperative and postoperative radiotherapy for rectal cancer to assess the differences in survival and side effects between these two treatment modalities,to provide a rational treatment foundation for radiation therapy for rectal cancer.Materials and Methods:A retrospective comparative analysis of 91 cases between with preoperative and postoperative radiotherapy for rectal cancer was performed between January 2012 and January 2016 at the China-Japan Union Hospital of Jilin University.Among them,39 cases were treated with preoperative radiotherapy,with an average age of 52.8 years old;52 patients who were treated with postoperative radiotherapy had an average age of 55.2 years old.Biopsy pathology in both two groups had been confirmed adenocarcinoma.In the preoperative group,the MRI imaging confirmed stage ?/?,and the total pelvic radiation dose was DT 44 Gy/ 22 f,the dose increased to 50 Gy if circumferential marginal resection margin is positively.Single drug concurrent chemotherapy with Capecitabine was giveb during radiotherapy.TME was performed 6-8 weeks later after radiotherapy,and 4-8 cycles of XELOX/FOLFOX chemotherapy were performed after surgery.In the postoperative group,pathologically confirmed stage ?/?,postoperative radiotherapy,DT 50 Gy/25 f in pelvic area,was given 2-3 weeks later after surgery,and concurrent chemotherapy with capecitabine during radiotherapy.Then 4-8 cycles XELOX/FOLFOX chemotherapy was given after chemoradiotherapy.Local recurrence,distant metastasis,overall survival,and side-effects were followed up and compared between the two groups within 2 years.Result:1.Local recurrence,distant metastasis,and survival after treatment The local recurrence rate of preoperative and postoperative radiotherapy for stage ?/? rectal cancer was 7.7% VS 25.0%,respectively(P<0.05);The 2-year distant metastasis rate was 23.1% VS 26.9%(P>0.05).The 2-year disease-free survival rate was 74.3% VS 67.3%,respectively(P>0.05);The 2-year overall survival rate was 84.6% VS 80.8%(P>0.05).2.Acute side effects in the treatment The rate of acute reaction of grade 1-2 with lower gastrointestinal tract in two groups was 61.5% VS 59.6%(P>0.05);the incidence of grade 3 reaction was 10.3% VS 26.9%(P<0.05);The incidence rate of 1-2 acute urinary tract reactions was 7.7% VS 9.6%(P>0.05);and the incidence of grade 3 reactions was 2.6% VS 3.8%(P>0.05).There were no grade 4 acute side effects in both groups.3.Treatment-related late-stage side effects The incidence of grade 1-2 side effects with late lower digestive tract in two groups was 53.8% VS 55.8%(P>0.05);the incidence of grade 3 reactions was 5.1% VS 19.2%(P<0.05).The incidence of grade 1-2 urinary tract reactions was 15.4% and 19.2%,respectively(P>0.05).The incidence of grade 3 reaction was 2.6% VS 5.8%(P>0.05).There were no grade 4 late-onset side effects in both groups.Conclusion:1.The local recurrence rate of preoperative radiotherapy significantly reduced within 2 years compared with postoperative radiotherapy in stage ?/? rectal cancer.2.,The acute and late response of grade 3 with lower digestive tract of preoperative radiotherapy reduced significantly when compared with postoperative radiotherapy in stage ?/? rectal cancer.3.When preoperative radiotherapy compared with postoperative radiotherapy in stage ?/? rectal cancer,there was no significant difference in the acute and late response of grade 1-2 with lower gastrointestinal tract,acute and late response of the urinary tract at all grades,the 2 years overall survival,2 years disease-free survival and the rate of distant metastasis.4.Preoperative radiotherapy for stage ?/? rectal cancer is a radiotherapy model that is effective,safe,with low local recurrence rate and relatively low acute and late toxicity with lower gastrointestinal tract.