Nomograms to predict survival and the risk for developing local or distant recurrence in patients with rectal cancer treated with optional short-term radiotherapy

Abstract

Background: In many European countries, short-term 5 × 5 Gy radiotherapy has become the standard preoperative treatment of patients with resectable rectal cancer. Individualized risk assessment might allow a better selection of patients who will benefit from postoperative treatment and intensified follow-up.

Patients and methods: From patient's data from three European rectal cancer trials (N = 2881), we developed multivariate cox nomograms reflecting the risk for local recurrence (LR), distant metastases (DM) and overall survival (OS). Evaluated variables were age, gender, tumour distance from the anal verge, the use of radiotherapy, surgical technique (total mesorectal excision/conventional surgery), surgery type (low anterior resection/abdominoperineal resection), time from randomization to surgery, residual disease (R0 versus R1 + 2), pT-stage, pN-stage and surgical complications.

Results: Pathological T- and N-status are of vital importance for an accurate prediction of LR, DM and OS. Short-course radiotherapy reduces the rate of LR. The developed nomograms are capable of predicting events with a validation c-index of 0.79 (LR), 0.76 (DM) and 0.75 (OS). The proposed stratification in risk groups allowed significant distinction between Kaplan-Meier curves for outcome.

Conclusion: The developed nomograms can contribute to better individual risk prediction for LR, DM and OS for patients operated on rectal cancer. The practicality of the defined risk groups makes decision support in the consulting room feasible, assisting physicians to select patients for adjuvant therapy or intensified follow-up.

Keywords: local recurrence; metastases; nomogram; prediction; rectal cancer; short-term radiotherapy.