Validation of a rectal cancer outcome prediction model with a cohort of Chinese patients

Abstract

The risk of local recurrence (LR), distant metastases (DM) and overall survival (OS) of locally advanced rectal cancer after preoperative chemoradiation can be estimated by prediction models and visualized using nomograms, which have been trained and validated in European clinical trial populations. Data of 277 consecutive locally advanced rectal adenocarcinoma patients treated with preoperative chemoradiation and surgery from Shanghai Cancer Center, were retrospectively collected and used for external validation. Concordance index (C-index) and calibration curves were used to assess the performance of the previously developed prediction models in this routine clinical validation population. The C-index for the published prediction models was 0.72 ± 0.079, 0.75 ± 0.043 and 0.72 ± 0.089 in predicting 2-year LR, DM and OS in the Chinese population, respectively. Kaplan-Meier curves indicated good discriminating performance regarding LR, but could not convincingly discriminate a low-risk and medium-risk group for distant control and OS. Calibration curves showed a trend of underestimation of local and distant control, as well as OS in the observed data compared with the estimates predicted by the model.In conclusion, we externally validated three models for predicting 2-year LR, DM and OS of locally advanced rectal cancer patients who underwent preoperative chemoradiation and curative surgery with good discrimination in a single Chinese cohort. However, the model overestimated the local control rate compared to observations in the clinical cohort. Validation in other clinical cohorts and optimization of the prediction model, perhaps by including additional prognostic factors, may enhance model validity and its applicability for personalized treatment of locally advanced rectal cancer.

Predictors of 1‐ and 2‐year mortality in patients with rectal cancer

“…The level of haemoglobin and the presence of residual tumour after surgery have also been reported as independent prognostic factors for mortality in elderly patients with rectal cancer . Other studies suggest that the pathological tumour stage (TNM) as well as adjuvant chemotherapy are prognostic factors . In our study, gender, lymph node ratio, carcinoembryonic antigen value, ASA and radiotherapy had no role in predicting mortality, even though some of them did so in the univariable analysis.…”

“…Other studies suggest that the pathological tumour stage (TNM) [17] as well as adjuvant chemotherapy are prognostic factors [18][19][20]. In our study, gender, lymph node ratio, carcinoembryonic antigen value, ASA and radiotherapy had no role in predicting mortality, even though some of them did so in the univariable analysis.…”

Prospective validation of pathologic complete response models in rectal cancer: Transferability and reproducibility

“…The quality of cohorts from clinical trials are needed to identify which variables need to be reported in clinical practice. Afterwards, training/validating models (using the methods explained here) on routine clinical data would increase the cohorts available to learn/validate upon as was done by Shen et al . Furthermore, validation in a clinical setting could also reduce the turnaround time between developing/validating and using predictive models in clinical practice; enabling rapid learning healthcare and subsequently decision support …”

“…28,29 The quality of cohorts from clinical trials are needed to identify which variables need to be reported in clinical practice. Afterwards, training/validating models (using the methods explained here) on routine clinical data would increase the cohorts available to learn/validate upon as was done by Shen et al 30 Furthermore, validation in a clinical setting could also reduce the turnaround time between developing/validating and using predictive models in clinical practice; enabling rapid learning healthcare and subsequently decision support. 2,3 When evaluating the results, the significance of the univariate differences (P-values between training and validation cohort; Tables I, II and III) generally overlapped with the multivariate cohort differences, described by the covariate weight P-values (Table IV).…”

Possible contribution of IMRT in postoperative radiochemotherapy for rectal cancer: analysis on 1798 patients by prediction model

“…Recently a study provided a nomogram based on five RCT in preoperative setting which accurately predicted the rate of overall survival, local recurrence and distant metastases, and that was successfully validated by a Chinese dataset [8, 9]. The aim of our study was to identify similar predicting factors of overall survival in postoperative rectal cancer patients and combine them into a nomogram for individualized treatment and further clinical trial design.…”