Given patients with substantial LVSI experience a pelvic recurrence rate of ~25%, how do you counsel patients with stage IA endometrioid endometrial cancer with LVSI regarding the relative risks/benefits of EBRT versus VBT alone?   

This is a really challenging clinical scenario! The PORTEC combined analysis finds substantial LVSI to be a significant risk factor for locoregional and distant recurrence. The trouble is that patients on PORTEC-1 and -2 did not have routine pathologic lymph node assessments. There are mixed data if...

Updated analysis of PORTEC-1 and 2 noted that 5-year pelvic lymph node recurrence was 26.3% when >4 vessels had LVSI involvement, compared to 6.7% with 1-3 foci and 3.3% with no LVSI1. Based on the data from PORTEC-2 which randomized patients to vaginal cuff brachytherapy or EBRT, on multivariabl...

It’s important to know two things. How substantial LVSI was defined and if nodal assessment was done? Here are two studies highlighting these aspects.Pifer et al., PMID 36893818Pifer et al., PMID 32718729 

I think an important distinction here is to ensure that the LVSI is, in fact, substantial by the PORTEC criteria. The 25% pelvic recurrence rate in patients with substantial LVSI was observed in the re-analysis of PORTEC1/2 using the 3-tiered approach. In this study, only ~5% of patients had substan...

Just LVSI alone without # of vascular space involvement is not adequate enough for making treatment considerations. The other possible cause of recurrence is the grade of the tumor. VBT in this case.