ESTRO 2021 Abstract Book

S1073

ESTRO 2021

Results 28 patients were enrolled and received study treatment between August 2018 and May 2020.The median age was 52(range, 34–67) years. T he median previous treatment lines were 2 (range, 2–5). As of Jan 1, 2021, median follow-up was 10.18 months (range, 3.4–29). 12of 28 (42.9%; 95%: CI 23.5-62.3) patients who had at least one post-baseline tumor assessment (efficacy evaluation population) achieved an objective response, including 3 (10.7%) complete response(CR), and 9 (32.1%) partial response(PR). The median duration of response was 1.57months(range,0.9 –2.17). The DCR was 82.1% (95% CI: 67.3% -97.2%) . Median progression-free survival (PFS) was 4.7 months (95% CI: 1.2-18.6). The one-year survival rate was 54.8%, and the longest administration time was 18.2 months.10 (35.7%) patients had grade 3 or 4 treatment-related adverse events (TRAEs), which occurring in ≥ 5% of patients were hypertension (7.1%), emesis (7.1%) and myelosuppression (7.1%). No treatment-related deaths were recorded.Notably, one patient discontinued maintenance therapy after 13 months because of coronary artery stenosis which is a rare toxic side effect of apatinib. Table 1 The Efficacy of apatinib plus capecitabine in treatment of recurrent/metastatic and persistent

cervical cancer after radiochemotherapy Evaluation of therapeutic efficiency N (%) CR 3 (10.7%) PR 9 (32.1%) SD 11 (39.3%) PD 5 (17.9%) ORR (CR + PR)

12(42.9%) (95% CI: 23.5%- 62.3%)

DCR (CR + PR+SD)

23(82.1%) (95% CI: 67.3% -97.2%)

Conclusion Apatinib plus capecitabine showed promising antitumor activity and tolerable toxicities in patients with recurrent/metastatic and persistent cervical cancer after chemotherapy.

PO-1307 Extended nodal radiotherapy for relapsed gynecologic tumors with PET/CT-guided SIB S.L. Villa 1 , A. Fodor 2 , R. Tummineri 2 , F. Zerbetto 2 , C.L. Deantoni 2 , S. Baroni 1 , A. Sanchez Galvan 1 , G. Mandurina 1 , P. Pacifico 1 , P. Mangili 3 , A. Del Vecchio 4 , S. Arcangeli 5 , N.G. Di Muzio 6 1 IRCCS San Raffaele Scientific Institute / University of Milano-Bicocca, Radiation Oncology, Milan, Italy; 2 IRCCS San Raffaele Scientific Institute, Radiation Oncology, Milan, Italy; 3 IRCCS San Raffaele Scientific Institute, Medical Physiscs, Milan, Italy; 4 IRCCS San Raffaele Scientific Institute, Medical Physics, Milan, Italy; 5 University of Milano-Bicocca, Radiation Oncology, Milan, Italy; 6 IRCCS San Raffaele Scientific Institute/ Vita e Salute University, Radiation Oncology, Milan, Italy Purpose or Objective Stereotactic Radiotherapy is the salvage treatment commonly used for the lymph-nodal (LN) recurrence, but often relapses occur near the irradiated area. Here we report outcomes and toxicity of a different approach based on extended nodal radiotherapy (ENRT) with simultaneous integrated boost (SIB) on fluoro-deoxy- glucose positron emission tomography/computed tomography (PET/CT) positive LN in gynecological cancer patients (pts) with LN recurrence. Materials and Methods From March 2007 to September 2020, 26 gynecological cancer patients with LN relapse after previous radical therapies were treated with salvage ENRT and SIB PET/CT-guided in our Institution. Primary tumor was: ovarian cancer for 11 pts, endometrial carcinoma for 9 pts, cervix carcinoma for 5 pts and vulvar carcinoma for 1 patient. A simulation PET/CT scan in treatment position was performed in 24/26 pts to identify the metabolic gross tumor volume PET (GTV-PET); in two pts GTV-PET was identified on diagnostic PET/CT. A 5 mm isometric margin was added to GTV-PET to obtain the planning target volume (PTV)-PET. Clinical target volume (CTV) included the LN chain of interest: pelvic, para-aortic or mediastinal. PTV was obtained by adding a 7 mm isotropic margin to CTV. A total dose of 50.4 Gy/28 fractions was prescribed to PTV. A SIB was prescribed to PTV-PET in 25/26 pts to achieve a mean dose of 62 (54-65.5) Gy. The treatment was delivered with helical IMRT/VMAT. Daily set-up correction with MVCT/kVCT was performed. Results Median follow-up was 36 (3.4 – 133.6) months. Acute and late toxicities are reported in Table 1. Few pts experienced only low grade late toxicities. The 6-month follow-up PET/TC scans showed complete response in 68% of pts, partial response in 11.5% of pts, and progressive disease in 20.5% of pts (in all distant metastases). Three years DFS was as follows: 15% of pts had local (one patient) or regional (three patients) recurrences and 61.5% developed systemic progression (including the patient with local relapse). In one patient the metastatic disease was diagnosed during radiotherapy. Three-year raw overall survival was 73%; 27% were dead due to disease progression.