ESTRO 2024 - Abstract Book

S977

Clinical - Gynaecology

ESTRO 2024

p=0,039, and SUVmax in metastatic para-aortic lymph nodes p=0,034 in IIIC2 group correlated with a better response to CT. However, in both groups of patients, a higher MTV in the first FDG PET-CT was associated with a shorter PFS (p=0,021, p=0,044) and OS (p=0,026, p=0,013). In addition, in the IVB group, a relationship was demonstrated between a higher TLG value and a shorter OS (p=0,03). Obtaining a response to CT (CR or PR) in the group of IIIC2 was associated with prolonged 3y OS (SD or PD 0 % vs. CR or PR 65,6%, p<0,001). CR or PR in the group of IVB was associated only with an improvement in PFS (p=0,019). The addition of RT in a group of IVB patients with CR or PR after CT showed a tendency to prolong OS compared to patients without RT (p=0,064).

Conclusion:

The assessment of the response to CT with FDG PET-CT in stage IIIC2 and IVB CC delivered the metabolic parameters that correlated with prognosis. CT followed by radical RT improves OS in stage IIIC2 and PFS in stage IVB in our study. The use of RT in patients in stage IVB, after obtaining a response to CT showed a tendency to improve OS. However, including a more significant number of patients or extending the follow-up time may influence the results and lead to statistical differences in this aspect.

Keywords: cervical cancer, FDG PET-CT, chemotherapy,

347

Proffered Paper

The impact of molecular classification on adjuvant radiotherapy choice for early endometrial cancer

Otilia Ciobanu 1 , Yixuan He 2 , Alicia R. Martin 2 , Jill S. Remick 3 , Joseph W. Shelton 3 , Tony Y. Eng 3 , David C. Qian 3

1 The Oncology Institute Al Trestioreanu, Department of Radiation Oncology, Bucharest, Romania. 2 Massachusetts General Hospital and Harvard Medical School, Analytic and Translational Genetics Unit, Department of Medicine, Boston, USA. 3 Winship Cancer Institute of Emory University, Department of Radiation Oncology, Atlanta, USA

Purpose/Objective:

Molecular classification (MC) is predictive of response to adjuvant radiotherapy for early-stage endometrial cancer (EC).(1) We sought to assess the differences in risk-adaptive adjuvant RT guided by traditional clinicopathologic features versus molecular classification for early-stage endometrioid EC.

Material/Methods:

Between 2002 and 2013, 253 women across 21 institutions with newly diagnosed FIGO 2009 I stage endometrioid EC and known adjuvant RT status submitted tumor specimens to The Cancer Genome Atlas (TCGA). We excluded the 100 patients with MMRd classification from treatment evaluation (Figure 1), as evidence suggests their RT benefit varies with some clinicopathologic features(1) that are not recorded in TCGA (e.g. lymphovascular space invasion).(2) For the remaining patients, we compared their documented adjuvant RT treatments (which all pre dated TCGA’s introduction of EC MC) with RT approaches informed by modern MC.

Figure 1. Study schema