P153 DEVELOPMENT OF A NOMOGRAM FOR THE PREDICTION OF INTERVAL METASTASES AFTER CHEMORADIOTHERAPY IN PATIENTS WITH ESOPHAGEAL SQUAMOUS CELL CARCINOMA
Abstract Aim To develop a nomogram for predicting interval metastases during chemoradiotherapy(CRT) in esophageal squamous cell carcinoma(ESCC) patients. Background&Methods During CRT for esophageal cancer, some patients develop systemic metastasis. Nomograms incorporating multiple prognostic factors are useful for individualized estimation of survival in cancer patients. However, nomograms for the prediction of interval metastases after CRT in patients with esophageal cancer are scarce. We retrospectively reviewed the records of 358 ESCC patients who underwent CRT as first line treatment. Data were subjected to multivariate logistic regression analyses for selecting variables to be included in the nomogram. The performance of the resulting nomogram was internally and externally validated by calculating the bias-corrected concordance statistic (c-statistic) and the area under the receiver operating characteristics curve (AUROC). Results After CRT, 21 patients (5.9%) were found with new distant metastatic lesions. The following variables were included in the nomogram: 1) age, 2) Tumor SUXmax on pretreatment18F-FDG PET, 3) pretreatment tumor length, 4)chemotherapy regimen (Paclitaxel+Carboplatin v.s. Fluorouracil+Cisplatin). The bias-corrected c-statistic and AUROC was 0.7094. Conclusions At least 5.9% of ESCC patients developed interval metastasis after CRT. Our nomogram showed an adequate performance for predicting interval metastases in ESCC patients.