PM11 - Definition and Prediction of Early Recurrence and Mortality Following CRS HIPEC: Predicting Futility Preoperatively
Sunday, February 16, 2020
7:30 AM – 7:45 AM
Location: Sebastian I 1/2
Introduction: For patients with colorectal peritoneal metastases (CRPM) cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) can offer significant survival advantage. Early recurrence remains a significant hurdle. Preoperative identification of patients at risk for early recurrence and poor survival following CRS-HIPEC would enable optimal treatment decisions and improve patient outcomes.
Methods: Patients who underwent CRS-HIPEC for CRPM from 2000-2018 were included. A minimum p-value approach was used to determine the optimal definition of early post-CRS-HIPEC recurrence based on its prediction of overall survival. Patients were then divided into early (ER) and late recurrence (LR) cohorts. Risk factors for ER were assessed by multivariate logistic regression. A predictive score for ER was generated via beta coefficient method using preoperative variables.
Results: 402 patients were identified, 339 (84.3%) had documented recurrence. Optimal length of post-operative RFS to distinguish ER (n=137, 40.4%) versus LR (n=202, 59.6%) was 8 mos (p<0.001). ER patients had significantly shorter median OS post-CRS-HIPEC compared to LR (13.8 vs 32.4 mos, p<0.001). Preoperative risk factors for ER included female sex (OR 1.81, p=0.009), hepatic lesions (OR 1.71, p = 0.045), poorly differentiated tumors (OR 1.68, p=0.04), PCI scores above 20 (OR 1.44, p=0.10), progression on neoadjuvant (OR 2.03, p=0.023), and <6 mos from presentation to diagnosis of CRPM (OR 1.45, p=0.10). Using this model, patients were assigned risk scores from 0-9. Scores ≥6 were classified as high risk. High risk patients (n=29, 7.2%) had an observed rate of ER of 79%. Overall 2- and 5-year survival rates for high risk patients were 13% and 3% respectively. The model showed fair discrimination (AUC 0.7) and good calibration (Hosmer-Lemeshow GOF p= 0.81).
Discussion: Early recurrence, defined here as recurrence within 8 mos of CRS-HIPEC, predicts markedly worse OS following surgery. Preoperative factors can accurately determine patients at high risk for ER using a simple risk score and identify patients in whom CRS-HIPEC for CPRM is futile.