An external validation study of nomograms designed to predict isolated loco-regional and distant endometrial cancer recurrences: how applicable are they?
Background:To externally validate and assess the robustness of two nomograms to predict the recurrence risk of women with endometrial cancer (EC).Methods:Using an independent, multicentre external patient cohort we assessed the discrimination and calibration of two nomograms – the 3-year isolated loco-regional (ILRR) and distant (DR) recurrence nomograms – in women with surgically treated stage I–III EC.Results:Two hundred and seventy one eligible women were identified from two university hospital databases and the Senti-Endo trial. The median follow-up and initial recurrence time were 38.1 (range: 12–69) and 22.0 (range: 8.3–55) months, respectively. The overall recurrence rate was 13.8% (37 out of 271). Predictive accuracy according to the discrimination was 0.69 (95% CI, 0.58–0.79) and 0.66 (95% CI, 0.60–0.71) for the 3-year ILRR and DR nomograms, respectively. The correspondence between observed recurrence rate and the nomogram predictions suggests a moderate calibration of the nomograms in the validation cohort.Conclusion:The nomograms were externally validated and shown to be partly generalisable to a new and independent patient population. The tools need to be improved by including information on the lymph node status and adjuvant therapies.