ESTRO 2024 - Abstract Book

S1093

Clinical - Gynaecology

ESTRO 2024

All patients were treated with surgery (CX) (hysterectomy + double adnexectomy). Considering adjuvant treatment, intermediate risk (IR) patients were considered if they had two of the three following risk factors: lymphovascular space invasion (LVSI), stromal invasion > ⅔ or tumor size >4 cm. High risk (HR) patients were considered if they met one of the following criteria: Positive margin, positive parametria or positive node status. IR and HR patients were treated with adjuvant radiotherapy (IMRT or 3DRT) or CRT. In selected cases with positive or proximal vaginal margin, patients were treated with 3D-based planning intracavitary brachytherapy. Primary endpoint was to calculate the 5-year overall survival (OS) and local recurrence-free survival rates (LRFS), comparing the surgery-exclusive (CX) group with the adjuvant radiotherapy (RT) group. Toxicity was evaluated according to CTCAE v.5.0 criteria.

Statistical analysis: Chi-Square test for comparing proportions, Kaplan Meier for survival analysis and Log-Rank for curve comparison.

Results:

Seventy low risk patients were treated with exclusive CX (72.2%) and 27 patients (27.8%) with IR (15/27; 55.5%) and HR (12/27; 44.4%) received adjuvant RT or CRT, respectively with or without vaginal brachytherapy.

After a median follow-up period of 66 months, 5-year OS was 93.7% (95% CI 88.3-99.1%), with LRFS rate of 91.2% (95% CI 85.2-97.2%).

When analyzed by sub-groups, the 5-year OS and LRFS rates in the CX group were 98.2% (95% CI 96.2-100%) and 89.2% (95% CI 89.2-97%), respectively. The corresponding rates in the RT group were OS 83.5% (95% CI 68.3 98.7%), and LRFS 96.2% (95% CI 85.9-100%). Furthermore, we stratified both group rates by tumor size, specifically <3 cm and ≥ 3 cm, to see if there were differences in LRFS. In tumors <3 cm, no differences were observed between both treatments in terms of local relapse (LR). However, for tumors ≥ 3 cm, a statistically significant difference was noted in 5-year LRFS between the CX group (71.4%; 95% CI 50.9-99.6%) and the RT group (87.5%; 95% CI 69.5-100%); p = 0.03. Figure 1 ). Analyzing the CX group, comparing the median tumor size on patients with LR (7/70; 10%) versus without LR (63/70; 90%), we find a statistically significant difference between both groups (Mean tumor size LR CX group: 2.41 cm; 95% CI 1.55-3.27cm; non-LR CX group: 1.04cm; 95% CI 0.63 - 2.01cm; p=0.001) Related to toxicity, we observed an overall rectal morbidity (diarrhea, proctitis and/or bleeding), in 15 patients: G1 9/15 (60%), G2 1/15 (6.67%) and G3 5/15 (33.3%). Urinary morbidity (urgency, incontinence, cystitis and/or hematuria) was observed in 24 patients: G1 13/24 (54.17%), G2 2/24 (8.33%) and G3 9/24 (37.5%).No G2-3 vaginal stenosis was observed. No sacrum fracture was observed.