ESTRO 2023 - Abstract Book

S1144

Digital Posters

ESTRO 2023

PO-1415 Radiotherapy as Definitive Treatment for Vulvar Carcinoma

C.F. de Sa 1 , J. Fonseca 1 , M. Fortunato 1 , R. Colaço 1 , F. Santos 1

1 Instituto Português de Oncologia Francisco Gentil, Radioterapia, Lisboa, Portugal

Purpose or Objective To evaluate clinical outcomes after definitive radiotherapy (RT) for carcinoma of the vulva.

Materials and Methods Single center retrospective analysis of women diagnosed with vulvar carcinoma between January 2013 to December 2019 treated with definitive RT. 3-year overall survival (OS), progression-free survival (PFS),were calculated using Kaplan-Meier method and the cumulative incidence of local, inguinal and distant relapse was calculated using competing risk models considering death without prior recurrence as a competing event. The association of concomitant chemotherapy and interruption of RT with OS and PFS was evaluated using Cox proportional hazards regression controlling for the confounding variables, age at diagnosis, disease stage and HIV infection. These confounding variables were defined a priori based on clinical criteria. We considered a significance level of 5%. Acute toxicity was assessed according to the Common Terminology Criteria for Adverse Events v 5. Results Eighty-one women were included. Median follow-up was 60 months (5 years). Median age at diagnosis was 78 years (range 42-95), squamous cell carcinoma (SCC) was the most frequent histology (n=70, 98%). FIGO 2009 stage were II 31%, III 35%, IVA 13% and IVB 20%. All patients were treated with intensity modulated radiotherapy (IMRT). Median dose to primary tumor was 70 Gy (36-70). Thirty-five patients received concurrent chemotherapy, most commonly cisplatin + 5FU (80%). Median total treatment time of RT was 55 days (25-133), 13 patients (16%) interrupted RT treatment due to worsening of clinical status or skin toxicity. Skin toxicity was the most common acute toxicity, G3 37(46%) and G4 2(2%). There were no acute G3 or G4 gastrointestinal or genitourinary toxicity. The 3-year cumulative incidence of local recurrence was 33.3%, inguinal and distant recurrence were 7.4%. Median OS and PFS were 12.1 (95%CI, 10.3-15.1) and 6.8 months (95% CI, 5.7-10.3), respectively. The 3-year OS was 14.8% (95%CI, 8.8%-25%) and PFS was 9.9% (95% CI, 5.1%-19.1%). Multivariable analyses showed a significant deleterious effect of interruption of RT on OS (HR=2.17; 95% CI, 1.15-4.0; P=0.016) and in PFS (HR=2.48; 95%CI 1.31-4.69; P=0.005). Conversely, concomitant chemotherapy had a beneficial effect on OS, although not statistically significant (HR=0.52; 95%CI, 0.98-1.05; P=0.09), and on PFS (HR=0.48; 95%CI 0.24-0.97; P=0.04). Conclusion Definitive RT for advanced vulvar carcinoma is associated with acceptable rates of locoregional control and treatment related toxicity. Interruption of RT treatment was significantly associated with decreased OS and PFS. Concomitant chemotherapy seems to be associated with increased OS and with increased PFS. PO-1416 Usefulness of magnetic resonance imaging in the pre-surgical evaluation of endometrial cancer M. Cerrolaza 1 , A. Mendez 1 , V. Navarro 1 , A. Miranda 2 , A. Lanuza 1 , A. Campos 1 , M. Gascón 3 , S. Flamarique 4 , R. Ibañez 1 1 University Hospital Miguel Servet, Radiation Oncology, ZARAGOZA, Spain; 2 National Oncological Institute "Dr. Juan Tanca Marengo" (SOLCA), Radiation Oncology, Guayaquil, Ecuador; 3 University Clinical Hospital Lozano Blesa, Radiation Oncology, ZARAGOZA, Spain; 4 Navarra Hospital Complex, Radiation Oncology, ZARAGOZA, Spain Purpose or Objective The staging of endometrial carcinoma (EC) is surgical but magnetic resonance imaging (MRI) is the most important imaging method to establish pre-surgical staging, which allows surgical treatment planning. It is a highly specific technique for diagnosing the depth of myometrial invasion, cervical stromal involvement, and lymph node metastases. The objective of this study is to evaluate the usefulness of preoperative staging by MRI in EC in our center. Materials and Methods Patients diagnosed with EC in our center between 2015 and 2021 were selected. Of these, patients who underwent pre surgical MRI for staging were analyzed. The pre-surgical FIGO MRI stage was collected, as well as the definitive anatomopathological FIGO stage. Univariate and multivariate analyzes were performed. Results Of the 348 patients with EC, 206 patients (59.19%) were analyzed. 78 patients (37.8%) were classified as stage IA, 100 (48.5%) IB, 12 (5.8%) II, 13 (6.3%) III, of which 10 IIIC, and 3 patients (1.5%) stage IV. In the definitive pathological study, endometrioid histology was observed in 148 patients (71.8%) and non-endometrioid in 58; with a histological grade G1 in 34 patients (16.5%), G2 in 104 (50.48%) and G3 in 68 patients (33%). Lymphovascular invasion (LVI) was observed in 39 patients (18.9%) and the definitive FIGO classification was stage IA in 78 patients (37.9%), IB in 85 (41.3%), II in 18 (8.7%), III in 24 (11.7%) and stage IV in a single patient (0.5%). Statistically significant differences were found between the FIGO classification assessed in the pre-surgical MRI and the definitive pathological anatomy (PA) (p=0.001). Up to 46.6% of the patients presented a stage different from that established by MRI, being in 52.6% higher in the surgical piece. An erroneous preoperative diagnosis was made in 44.87% of patients diagnosed as FIGO IA, 43% of FIGO IB, 16.6% of FIGO II, 38.46% of FIGO III, and 100% of those initially classified as FIGO IV.