ESTRO 2022 - Abstract Book

S1151

Abstract book

ESTRO 2022

patients respectively. Grade 1 anaemia , grade 2 anaemia, grade 1 dermatitis and grade 2 dermatitis were observed in 3(15%), 2(10%), 3(15%) and 2(10%) patients respectively. Loco-regional control at 6 months was 95%.

Patient characteristics

Distribution (n=20)

Median Age (Range)

52 years (29-65 years)

Median KPS (Range)

90 (80-100)

Differentiation (Well: Moderate: Poor)

1(5%):16(80%):3(15%)

FIGO 2018 Stage IIA:IIB:IIIB:IIIC1 3(15%):8(40%):2(10%):7(35%) Abbreviations: KPS=Karnofsky performance status, FIGO = International Federation of Gynecology and Obstetrics; Table 1 showing patient characteristics.

Conclusion The combination of IG-IMRT and IGBT yielded excellent dose distribution to tumor volumes and sparing of OARs resulting in descent outcome in terms of acute toxicity profile and loco-regional control.

PO-1357 Comorbidity index and LVSI for treatment selection for intermediate risk endometrial cancer patients

J. Petsuksiri 1 , J. Setakornnukul 1 , A. Berpan 1 , K. Thephamongkhol 1 , P. Dankulchai 1 , A. Jaishuen 2

1 Faculty of Medicine Siriraj Hospital, Mahidol University, Radiation Oncology, Bangkok, Thailand; 2 Faculty of Medicine Siriraj Hospital, Mahidol University, Obstetrics and Gynecology, Bangkok, Thailand Purpose or Objective To compare treatment outcomes between pelvic radiotherapy (PRT) versus vaginal brachytherapy (VBT) as adjuvant treatment for intermediate-risk endometrial cancer patients. Specifically, this study aims to provide high risk factors that increase pelvic recurrences, requiring PRT in addition to VBT. Materials and Methods Patients with intermediate-risk endometrial cancer who received postoperative VBT alone or PRT with or without VBT were included. Primary endpoint was locoregional recurrence (LRR). Secondary endpoints were vaginal recurrence (VR), pelvic recurrence (PR), distant metastases (DM), overall recurrence (OR), progression free survival (PFS), cancer-specific survival (CSS), overall survival (OS) and complications. Specific risk factors were explored to indicate the benefits of PRT over VBT alone. Results From 2005 - 2017, 322 patients were included for analyses. There was no difference in 5-year LRR, VR, PR, DM, OR, CSS or OS, comparing between patients who received VBT versus PRT with or without VBT (table 1). Acute and late GI and GU toxicities were significantly higher in the PRT arm than VBT arm (grade 1-2 acute GI: 0% vs 54.4%; GU: 3.3% vs 17.2%; late GI: 1.3% vs 12.4%; GU: 1.3% vs 8.3%, p <0.001). On univariable and multivariable analyses, lymphovascular space invasion (LVSI) was a significant prognostic factor for OR (HR 4.71; 1.41-15.73, p= 0.012) and CSS (HR 3.04; 1.03-8.99, p=0.045), while high age-adjusted Charlson comorbidity index (ACCI) was independently associated with worse non-CSS (HR 1.78; 1.38-2.29, p<0.001) and OS (HR 1.51; 1.23-1.86, p<0.001). On specific analyses, PRT appeared to have better oncologic outcomes specifically in patients with ACCI of less than 4 and LVSI (figure 1). Table 1: Outcomes stratified by treatment groups

VBT alone (n=153) % (95% CI)

PRT with/without VBT (n=169) % (95% CI)

Absolute (95% CI)

difference %

Hazard ratio (95% CI, p-value)

5-year

-1.1 (-3.8 to 1.6)

LRR

0.8 (0.1-5.7)

1.9 (0.6 - 5.8)

0.37; 0.04 – 3.54, 0.387

-1.3 (-5.1 to 0.3)

VR

0

1.3 (0.3-5.1)

-

0.2 (-1.8 to 2.1)

PR

0.8 (0.1-5.5)

0.6 (0.1-4.2)

1.11; 0.07-17.67, 0.944

-0.8 (-5.0 to 3.3)

DM

3.0 (0.9-9.8)

3.4 (1.4-8.0)

0.73; 0.17 – 3.09, 0.674

-2.0 (-6.7 to 2.9)

OR

3.8 (1.3-10.5)

5.3 (2.7-10.4)

0.59; 0.18 – 1.96, 0.387

-2.3 (-7.8 to 3.2)

CSS

95.4 (89.0-98.1)

94.2 (89.1-96.4)

0.55; 0.19-1.56, 0.258

-3.4 (-9.3 to 2.5)

OS

95.0 (89.8-97.6)

91.4 (85.9-94.8)

0.67; 0.33 – 1.36; 0.265

Figure 1: Survival according to ACCI and LVSI