Development of a prediction model of adverse events after stent placement for esophageal cancer.
OBJECTIVE
Self-expandable metal stent (SEMS) positioning is the recommended method for palliation of dysphagia from esophageal cancer, although it is not adverse event-free. The present study was aimed at identifying predictors for adverse events and at proposing a statistical model to predict them.


METHODS
We performed a retrospective analysis of a prospectively collected database. All patients who underwent SEMS placement for stricture due to esophageal cancer between 2002 and 2011 in a tertiary-care center were identified. Multivariable regression analysis in the presence of competing risk events was used to identify factors associated with SEMS-related adverse events and to build a prediction model.


RESULTS
A total of 267 patients were included. According to the competing risk regression analysis, only 2 variables were significantly associated with the risk of SEMS-related adverse events: prior chemoradiotherapy (CRT), yielding a hazard ratio (HR) of 1.687 (95% confidence interval [CI], 1.076-2.644), and the SEMS length (HR 0.884; 95% CI, 0.798-0.980) for every 10-mm length increase. Based on the estimated probability curves, after 4 months from SEMS placement, the probability of an adverse event in patients who did receive prior CRT was 50.9% compared with 34.4% in those who did not receive prior therapy, which was reduced to 9.2% and 15.1%, respectively, if a 180 mm-length stent was used. The ability of the predictive model to differentiate between patients who did and did not experience the adverse event was moderate (c-index: 0.617).


CONCLUSIONS
The rate of SEMS-related adverse events was higher in patients with previous CRT and lower in patients receiving longer stents. Both factors were used to build an accurate predictive model.
Department of Medical and Surgical Sciences, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
Lorenzo
L
Fuccio
Department of Statistics, University of Bologna, Bologna, Italy.
Michele
M
Scagliarini
Department of Medical and Surgical Sciences, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
Leonardo
L
Frazzoni
Division of Endoscopy, Veneto Oncological Institute (IOV-IRCCS), Padua, Italy.
Giorgio
G
Battaglia
D000230:Adenocarcinoma / Q000150:complications* / Q000628:therapy; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000150:complications* / Q000628:therapy; D059248:Chemoradiotherapy; D016099:Endoscopy, Gastrointestinal; D004867:Equipment Design / Q000009:adverse effects; D004938:Esophageal Neoplasms / Q000150:complications* / Q000628:therapy; D004940:Esophageal Stenosis / Q000209:etiology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015999:Multivariate Analysis; D011336:Probability; D019919:Prosthesis Implantation / Q000009:adverse effects; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D000069322:Self Expandable Metallic Stents / Q000009:adverse effects*