ESTRO 2020 Abstract book

S646 ESTRO 2020

PO-1136 Combined intracavitary and interstitial brachytherapy in locally advanced cervical cancer. F. Piccolo 1 , B. Pappalardi 1 , M. Carrara 1 , C. Tenconi 1 , T. Giandini 1 , C. Delle Curti 2 , C. Fallai 1 , A. Cerrotta 1 1 Fondazione IRCCS Istituto Nazionale dei Tumori, Dipartimento di diagnostica per immagini e radioterapia, Milano, Italy ; 2 Università degli studi di Milano Bicocca, radioterapia, Milano, Italy Purpose or Objective To improve target volume coverage with the implementation of combined intracavitary and interstitial brachytherapy (ICIS-BT) in the locally advanced cervical cancer treatment. Material and Methods Intracavitary brachytherapy and external-beam radiotherapy (EBRT) is a standard treatment for locally advanced cervical cancer. In patients with large-volume tumors at the time of brachytherapy, with minor parametrial response, and/or in the case of unfavorable topography, intracavitary technique is not optimal choice. In these situations additional interstitial brachytherapy has been applied to improve target coverage. In our department, from October 2017 to October 2018, eleven patients were treated using combined ICIS-BT for primary cervical cancer. The morphological and/or dimensional features of the target volume (i.e. ≥30 cc) drove our choice. All patients received EBRT (VMAT) with concomitant chemotherapy and sequential brachytherapy boost. The prescribed dose was 45 Gy in 25 fractions over 5 weeks. Chemotherapy regimen was weekly Cisplatin (40 mg/m2). Image-guided adaptive brachytherapy (IGABT) based on magnetic resonance imaging (MRI) was performed for all 11 patients. According to GEC ESTRO working group, GTV, High Risk CTV (HR- CTV), Intermediate Risk CTV (IR-CTV), bladder, rectum and sigmoid were delineated at the time of each brachytherapy fraction on para-axial MR images with the applicator in place. Dose-volume histograms were calculated to evaluate doses to tumor target and organs at risk. The total dose prescribed was 28 Gy in 4 fractions. Acute genitourinary, gastro-enteric and vaginal toxicity was monitored at each fraction and recorded according to the CTCAE criteria version 4.03. The planning aims, according to the EMBRACE II protocol, have been achieved for all 11 patients. Also the hard constraints for the organs at risk were never exceeded. To demonstrated that the implementation of interstitial component was essential to improve target dose coverage, the treatment of the 11 patients were rescheduled avoiding interstitial needles dose contribution. The D90 to HR-CTV obtained with ICIS-BT and without the use of needles were compared. Results Brachytherapy treatment was well tolerated by all 11 patients. Patients didn’t show G3 toxicities or higher. Figure 1 shows the variation of the D90 CTV-HR for each of the eleven patients and one treatment fraction, with and without the contribution of the interstitial needles. The average gain in terms of target coverage was of 25% in favor of the ICIS-BT treatments. Conclusion Brachytherapy is a part of the standard treatment for cervical uterine cancers in the locally advanced stage. In patients with large-volume tumors at the time of brachytherapy, with minor parametrial response, and/or in the case of unfavorable topography, the implementation of the interstitial technique alongside the intracavity technique allows to guarantee an adequate coverage of the target, with a consequent better local control of the disease.

Fifty-eight patients (median age 67.5 years, range 48-86) entered the analysis. Overall, 34 patients (58.6%) showed negative 18F-FDG-PET/CT imaging, 6 patients (10.4%) had doubtful uptakes and 18 patients (31%) had an FDG intense uptake in different sites: pelvic disease, pelvic or paraaortic lymph nodes, metastases or an association of those possibilities. Patients without or with doubtful uptake underwent radiotherapy according to international guidelines, while among patients with pathologic uptake, 6 did not receive irradiation treatment: 4 patients due to distant metastasis that were treated with chemotherapy, one due to long lasting surgical complications and one for clinical decisions. On the contrary, 12 patients underwent to modified external beam radiotherapy based on 18F- FDG-PET/CT: 10 patients received a sequential or concomitant radiotherapy boost on the PET positive areas, one patient underwent to a vaginal cuff brachytherapy boost and one patient had an enlargement of the treated volume. Conclusion According to international guidelines, the role of 18F-FDG- PET/CT in the adjuvant setting of endometrial cancer is not yet clearly defined. In the present series we reported 31 % of cases in which the planned adjuvant treatment changed based on 18F-FDG-PET/CT findings. PO-1135 Place of radiotherapy as part of multimodal management of cervical glassy cell carcinoma J. Boustani 1 , S. Achkar 2 , A. Bartaut 3 , C. Genestie 4 , S. Gouy 5 , M. Kissel 2 , P. Pautier 6 , P. Morice 5 , C. Haie-Meder 2 , C. Chargari 2 1 Centre Georges François Leclerc, Radiation Oncology, Dijon, France ; 2 Gustave Roussy, Brachytherapy, Villejuif, France ; 3 Centre Georges François Leclerc, Biostatistics, Dijon, France ; 4 Gustave Roussy, Anotomopathology, Villejuif, France ; 5 Gustave Roussy, Gynecologic surgery, Villejuif, France ; 6 Gustave Roussy, Medical Oncology, Villejuif, France Purpose or Objective Objective: Glassy cell carcinoma (GCC) of the uterine cervix is a rare entity, accounting for 1-2% of all cervical carcinoma. This study aims at describing the clinical characteristics and outcomes of cervical GCC patients treated in a comprehensive cancer center. Material and Methods Material and Methods: We retrospectively reported patients and tumors characteristics, therapeutic management, overall survival (OS), progression-free progression (PFS), relapse rates, and toxicities. Results Results: Between 1994 and 2014, 55 patients were treated with curative intent. The median age at diagnosis was 41 years (range, 20-68). Among 22 patients with early stage tumors (IA2-IB1-IIA1), 17 had preoperative brachytherapy, followed by radical hysterectomy. Among 33 patients with locally advanced disease (≥IB2), 32 underwent chemoradiation +/- brachytherapy boost. After a median follow-up of 5.4 years (range, 0.15-21.7 years), 18/55 (33%) patients experienced tumor relapse. Local recurrence occurred in 2/22 (9%) patients with early disease (treated with upfront surgery) and in 3/32 (9%) patients with locally advanced disease. Most frequent relapses were distant, occurring in a total of 11/55 patients (20%). PFS rates at 5-year were 86.4% (95% CI: 63.4-95.4) for early stage versus 75.9 % (95%CI: 55.2-89.2) for locally advanced stages, respectively (p=0.18). Conclusion Conclusion: Large cohort data are warranted to guide the optimal management of GCC. From this retrospective analysis, a multimodal approach yielded to good disease control in early stages tumors. Given the high risk of distant failure, consideration should be given to adjuvant chemotherapy in locally advanced disease.