A clue towards improving the European Society of Medical Oncology risk group classification in apparent early stage endometrial cancer? Impact of lymphovascular space invasion

Background: Lymphovascular space invasion (LVSI) is one of the most important predictors of nodal involvement and recurrence in early stage endometrial cancer (EC). Despite its demonstrated prognostic value, LVSI has not been incorporated into the European Society of Medical Oncology (ESMO) classification. The aim of this prospective multicentre database study is to investigate whether it may improve the accuracy of the ESMO classification in predicting the recurrence risk. Methods: Data of 496 patients with apparent early-stage EC who received primary surgical treatment between January 2001 and December 2012 were abstracted from prospective multicentre database. A modified ESMO classification including six risk groups was created after inclusion of the LVSI status in the ESMO classification. The primary end point was the recurrence accuracy comparison between the ESMO and the modified ESMO classifications with respect to the area under the receiver operating characteristic curve (AUC). Results: The recurrence rate in the whole population was 16.1%. The median follow- up and recurrence time were 31 (range: 1-152) and 27 (range: 1-134) months, respectively. Considering the ESMO modified classification, the recurrence rates were 8.2% (8 out of 98), 23.1% (15 out of 65), 25.9% (15 out of 58), and 45.1% (28 out of 62) for intermediate risk/ LVSI -, intermediate risk/ LVSI-, high risk/ LVSI -, and high risk/ LVSI+, respectively (Po0.001). In the low risk group, LVSI status was not discriminant as only 7.0% ( 14 out of 213) had LVSI_. The staging accuracy according to AUC criteria for ESMO and ESMO modified classifications were of 0.71 ( 95% CI: 0.68- 0.74) and 0.74 ( 95% CI: 0.71- 0.77), respectively. Conclusions: The current modified classification could be helpful to better define indications for nodal staging and adjuvant therapy, especially for patients with intermediate risk EC.