Establishment And Validation Of Clinical Prediction Model For Postoperative Recurrence Of Marjolin's Ulcer

Background and ObjectiveMarjolin's ulcer(also called carcinoma of scar,referred to as MU)is a malignant transformation of burn,scar or other chronic wounds.The incidence rate of this disease is about 0.77%-2%worldwide.Meanwhile,compared with other types of skin cancer,the recurrence rate of Marjolin's ulcer is high.This study was to explore the risk factors of postoperative recurrence in patients with Marjolin's ulcer,establish a clinical prediction model and verify its predictive value,so as to reduce the postoperative recurrence rate of patients.Methods1.Retrospective analysis was performed on 131 patients with Marjolin's ulcer who underwent surgical resection in the First Affiliated Hospital of Zhengzhou University from November 2008 to November 2018.The clinical characteristics of the patients,including gender,age,initial injury or disease,lesion location,lack of treatment for initial injury or disease,latency period,lesion area,pathological type,pathological grading,bone invasion,lymph node metastasis,radiotherapy,and postoperative recurrence,were statistically analyzed,of the 131 patients with Marjolin's ulcer,the male patients were significantly more than the female patients,the ratio of male to female was about 1.6:1.0,and most of the patients were in the age group?50 years old;The most common cause of initial injury or disease was burn and scald(59.54%),followed by trauma(17.56%);The latency period>1 year was the most,accounting for 94.66%,the latency period<1 year accounted for 5.34%;The lesions are most common in the limbs,followed by the head and neck;The majority of patients had lack of treatment for initial injury or disease(59.5%);Tumor lesion area?10cm and<100cm was the largest(55.0%),followed by<10cm(20.6%);The main pathological types were squamous cell carcinoma(79.4%);The pathological grades of tumors were mainly well differentiation and moderately differentiation,and poorly differentiation was rare;Bone invasion occurred in 43 cases(32.8%),14 cases(10.7%)with lymph node metastasis;About 40.5%of the patients received radiotherapy after surgery;Patients discharged from the hospital were followed up for 12-36 months.There were 32 patients with recurrence,accounting for 24.4%.2.The least absolute shrinkage and selection operator regression model(LASSO)was used to optimize feature selection for the risk model of postoperative recurrence of Marjolin's ulcer,and the best predictor with non-zero coefficient was selected in the LASSO regression model.The optimal predictors were analyzed by multivariate logistic regression analysis,and the clinical prediction model was established.C-index,calibration curve and decision curve were used to analyze and evaluate the identification,calibration and clinical practicability of the prediction model.To evaluate the accuracy of the prediction model,Bootstrap method was used for internal validation.Results1.The predictors of statistical clinical characteristics include gender,age,initial injury or disease,lesion location,lack of treatment for initial injury or disease,latency period,lesion area,pathological type,pathological grading,bone invasion,lymph node metastasis,radiotherapy,a total of 12 factors.After optimization by LASSO,the prediction factors in the prediction model included 5 factors:lesion location,lack of treatment for initial injury or disease,pathological grading,bone invasion and lymph node metastasis.2.These five factors were analyzed by multivariate logistic regression and a prediction model was established.The model has good discrimination ability,C-index is 0.810(95%confidence interval:0.726-0.894),and the correction effect is good.The internal verification Bootstrap method can still reach a high C-index of 0.764.Decision curve analysis showed that the prediction model of postoperative recurrence of Marjolin's ulcer was clinically useful when the intervention was determined at a threshold of 6%-61%.Conclusions1.Nomogram of postoperative recurrence of Marjolin's ulcer can be easily used to predict the risk of postoperative recurrence of individual Marjolin's ulcer patients.2.The risk of postoperative recurrence is higher when the lesion is located in the limbs,head and neck,lack of treatment for initial injury or disease,low differentiation of tumor pathology,bone invasion and lymph node metastasis,measures such as expanding the surgical resection edge,amputation if necessary,and active radiotherapy after operation can be used to reduce the recurrence rate.3.Marjolin's ulcer is a preventable complication of initial injury or disease.Early identification,active treatment and close follow-up are essential for the prevention and improvement of prognosis of Marjolin's ulcer.