ESTRO 2023 - Abstract Book

S1151

Digital Posters

ESTRO 2023

D. Vallerossa 1,2 , A. Galuppi 3 , A. Benini 4 , E. Galietta 4 , L. Cavallini 4 , M. Buwenge 4 , G. Macchia 5 , S. CIlla 6 , S. Cammelli 7 , F. Romani 8 , L. Strigari 8 , A.G. Morganti 1 , M. Ferioli 1 1 Radiation Oncology, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum University of Bologna, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; 2 Radiation Oncology, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum University of Bologna, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; 3 IRCCS Azienda Ospedaliero-Universitaria di Bologna, Radiation Oncology Unit, Bologna, Italy; 4 Radiation Oncology, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum University of Bologna, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; 5 Università Cattolica del Sacro Cuore, Radiation Oncology Unit, Gemelli Molise Hospital, Campobasso, Italy; 6 Fondazione Policlinico Universitario A. Gemelli, IRCCS, Medical Physics, Gemelli Molise Hospital, Campobasso, Italy; 7 Radiation Oncology, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Alma Mater Studiorum University of Bologna, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; 8 IRCCS Azienda Ospedaliero Universitaria di Bologna, Medical Physics, Bologna, Italy Purpose or Objective Radiotherapy (RT) of vulvar cancer (VC) is a treatment option in both patients with advanced disease and in the adjuvant setting. Intensity Modulated RT (IMRT) and Volumetric Modulated Arc Therapy (VMAT) enable more conformal dose distribution and the delivery of higher doses to the target and lower doses to organs at risk. Here we report the results from an observational study on clinical outcome and toxicity in VC patients treated in our center with IMRT/VMAT Materials and Methods Vulvar cancer patients who underwent adjuvant or definitive IMRT or VMAT in our institution were included in this analysis. Toxicity, local control (LC), overall survival (OS), progression free survival and pattern of recurrence were evaluated. Results Forty-one patients were included. Median age was 77 years (range 46-93). Most patients were treated with IMRT, from 2016 to 2021. Adjuvant RT was delivered in 41.5% patients and definitive RT in 58.5%. The delivered RT dose to the vulva in the adjuvant and definitive settings ranged between 39.6–65 Gy and 32.4-66 Gy, respectively, while the dose to the inguinal nodes was 45-65 Gy and 32.4-66 Gy, respectively. Moreover, 48.8% of patients were treated for locally recurrent VC. Concurrent chemotherapy was used in 18 patients (44.0%). Most patients showed grade 2 (22%) or 3 (73.2%) skin acute toxicity while gastrointestinal and genitourinary toxicity affected fewer patients and with lower grades of severity. Treatment was not completed in 4.9% of patients. One- and 2-year LC was 68.3% and 55.7%, respectively, with better results in the adjuvant setting (two-year LC 67.9%). Two-year OS was 52.5 and 27.4% in patients treated with adjuvant and definitive RT, respectively (Figure 1), with a statistically significant difference (p 0.019).

Conclusion Vulvar cancer is a rare disease and most of available evidence is based on retrospective studies. Clinical outcome was not satisfactory in our patients, especially in those treated for local recurrence after previous surgery. Despite IMRT allows improved dose distribution, our data suggests that in an elderly population it is difficult to complete treatment without interruptions and to achieve satisfactory clinical outcomes. Moreover, skin toxicity remains an important limitation to deliver a high RT dose.

PO-1424 CBCT-guided online adaptive radiotherapy in patients with cervical cancer

L. Zwart 1 , S. Koch 1 , L. Haverkate 1 , E. Hendriksen 1 , E. Koiter 1 , J. Dasselaar 1

1 Medisch Spectrum Twente, Radiotherapy, Enschede, The Netherlands

Purpose or Objective