Establishment Of Preoperative Bowel Obstruction Risk Assessment Model For Colorectal Cancer Based On SEER-Medicare Database

Background: Bowel obstruction(BO)is a complication that commonly affects patients with colorectal cancer(CRC),it causes severe outcomes,and its treatment leads to a dilemma for many surgeons.And the factors correlated to BO with preoperative CRC patients still remain unclear.This study was to investigate the clinical characteristics of BO to identify predictors and construct a BO prediction model with preoperative CRC patients.Methods: A large-scale,retrospective cohort,population-based study analyzed the data of 11,814 patients obtained from the Surveillance,Epidemiology,and End Results and Medicare claims linked databases(SEER-M database).Patients aged ?66 years,primarily diagnosed with CRC from 1992 to 2009,were divided into BO and non-BO groups.Cox proportional hazards regression models were used to determine predictors and later constructed a nomogram by those predictors.Results: 11814 patients consisted of 5,293 men and 6,251 women were identified.In multivariate analysis,14 factors were associated with BO,including age,race,marital status,T category,M category,primary tumor site,histologic type,histologic grade,tumor size,history of alcoholism,abdominal pain,anemia,chemotherapy and radiotherapy.Age group 66-70 years old(HR=1.737,95%CI=1.558-1.935),Asian(HR=1.062,95%CI=0.887-1.271),married(HR=1.115,95%CI=1.028-1.208),patients with T4 a classification(HR=1.213,95%CI=1.108-1.328),patients with M classification unknown(HR=1.213,95%CI=1.108-1.328),patients with primary tumor located in the left-sided colon(HR=2.093,95%CI=1.892-2.315),patients with mucinous carcinoma pathologically(HR=1.593,95%CI=1.392-1.823),patients with low grade of pathological differentiation(HR=1.131,95%CI=1.022-1.251),patients with tumor size of 35-50mm(HR=1.266,95%CI=1.110-1.444),patients with abdominal pain(HR=1.202,95%CI=1.105-1.307)were risk factors.A history of alcohol abuse(HR=0.781,95%CI=0.627-0.973)and anemia(HR=0.802,95%CI=0.696-0.923)were protective factors for obstruction in colorectal cancer patients.Most of the chemotherapy is effective for obstruction,among which the most effective chemotherapy is 5-fu + oxaliplatin combined with bevacizumab compared with the patients without chemotherapy(HR=0.395,95%CI =0.292-0.535).Patients who received radiotherapy had a 40% lower risk of obstruction than those who did not receive radiotherapy(HR=0.591,95%CI=0.514-0.679).A nomogram predicting the 90-and 180-day rate of BO was built for the preoperative CRC patients with a c-index of 0.795.Conclusion: This study allowed the identification of 14 BO-related factors,and a statistical model was constructed to predict the onset of BO in preoperative CRC patients through these independent risk factors.This model can guide clinicians to screen patients with colorectal cancer for the risk of obstruction,and to carry out effective clinical intervention for patients with risk of obstruction.