Less favourable prognosis for low risk endometrial cancer patients with a discordant pre versus post operative risk stratification

Background:
Pre-operative risk stratification based on endometrial sampling determines the extent of surgery for endometrial cancer (ec). We investigated the concordance of pre- and post-operative risk stratifications and the impact of discordance on survival.

Methods:
Patients diagnosed with ec within the first 6 months of the years 2005-2014 were selected from the netherlands cancer registry (n = 7875). Pre and post operative risk stratifications were determined based on grade and/or histological subtype for 3784 eligible patients.

Results:
A discordant risk stratification was found in 10% of patients: 4% (n = 155) had high pre and low post operative risk and 6% (n = 215) had low pre and high post operative risk. Overall survival of patients with high pre and low post operative risk was less favourable compared to those with a concordant low risk (80% versus 89%, p = 0.002). This difference remained significant when correcting for age, stage, surgical staging and adjuvant therapy (hazard ratio 1.80, 95% confidence interval 1.28-2.53, p = 0.001). Survival of patients with low pre- and high post-operative risk did not differ from those with a concordant high risk (64% versus 62%, p = 0.295).

Conclusion:
Patients with high pre and low post operative risk have a less favourable prognosis compared to patients with a concordant low risk. Pre operative risk stratifications contain independent prognostic information and should be incorporated into clinical decision making.