Development of Margin Compromise Ordinal Score (MCOS) Based on Analysis of Various Factors Associated with Margin...

It's preferred by patients as well as surgeons to avoid permanent stoma in a patient of Carcinoma Rectum. But this should not be done at the cost of margin compromise. There is little literature on factors affecting margin status, therefore a comprehensive study to analyze all factors associated with margin status is required. This will not only allow surgeons to be cautious in a particular subgroup during surgery but also help in proper patient selection for restorative surgery. It's an observational study consisting of 77 patients of Carcinoma Rectum undergoing restorative radical surgery. Definition of close and clear radial/distal margin was standardized before the study. Patients were divided based on margin status - clear or close. Various clinical, laboratory and histopathological factors were analyzed for association with margin status. Continuous quantitative variables were analyzed using independent t-test. Discrete quantitative variables were analyzed by linear regression method. Qualitative variables were analyzed using Chi square test. p value was considered significant at p < 0.05. All factors found significantly associated with radial or distal margin compromise on histopathological examination were calculated and used for formulating a score predicting odds/probability of getting margin compromise using logistic regression. After the score was formulated, the probability of getting margin compromise in all those with actual margin compromise was calculated. Probability less than 1st quartile was taken as low, between the 1st and 3rd quartile as intermediate and more than 3rd quartile was taken as high risk for margin compromise, thus providing an ordinal scale. Significant association of body habitus (p = 0.00025) and node positivity (p = 0.034) with circumferential margin compromise was found. Similarly, distal margin compromise was found significantly associated with tumor location/distance from anal verge (p = 0.004) and if it's low rectal tumor, then tumor diameter (p = 0.00001, Pearson's coefficient of = 0.47) also played a significant role in distal margin. Utilizing these factors, a scoring system was developed using multivariate logistic regression, predicting odds of margin compromise. Odds of radial margin compromise = e - 1.694 - (1.585 (Ifpatient is obese), -1.256 (If patient is overweight)) +1.355 (If nodes are positive on imaging) Odds of distal margin compromise = e2.778 - (0.415 × Distance from anal verge) - (0.043 × Maximum diameter of tumor if tumor is located in lower rectum) Using 1st and 3rd quartile of margin compromise probabilities, an ordinal scale classifying margin compromise risk into low, intermediate and high. Margin Compromise Ordinal Scale (MCOS) is a proposed tool to objectively predict risk of margin compromise. It will help oncosurgeons/colorectal surgeons to take appropriate neoadjuvant actions or avoid restorative surgery in individuals at high risk of margin compromise.