ESTRO 38 Abstract book

S811 ESTRO 38

(EBRT) and brachytherapy three-channel (BTC) for cervical cancer patients of Oriental origin. Material and Methods An anatomical vaginal reference was defined at the level of the Posterior–Inferior Border of Symphysis (PIBS) for both EBRT and BTC. 5 additional points from PIBS -2cm to PIBS + 3cm which corresponds to the level of the vaginal introitus to the upper vagina were also defined. Doses to all these 6 points were recorded. A vaginal reference length (VRL) was defined from the centre of vaginal top to the PIBS. The dose reporting method was applied to all patients. Data from all patients, treated for cervical cancer having received combined prescriptions of 50.4Gy in 28fractions and 28Gy in 4 fractions for EBRT and BTC respectively, over the last 12 months were extracted. This was then compared to an all Caucasian population.

Medical Physics, Pavia, Italy ; 5 National Centre of Oncological Hadrontherapy CNAO- University of Pavia, Radiation Oncology- Department of Clinical-Surgical- Diagnostic and Pediatric Sciences, Pavia, Italy ; 6 National Centre of Oncological Hadrontherapy CNAO- European Institute of Oncology, Radiation Oncology, Pavia- Milano, Italy Purpose or Objective Recurring gynecological tumors of the pelvic area within or at the edge of a previously irradiated field are often in close proximity to the intestinal tract. When surgery is not feasible, re-irradiation can be reasonably used. Re- irradiation presents challenges due to the high cumulative dose and the risk of severe toxicities in normal tissues. Particle therapy (with carbon ions and protons) is a promising alternative for these women. Material and Methods Between May 2014 and October 2018, 8 patients with gynecological recurrent tumor within or at the edge of the previously irradiated field were admitted for particle therapy at National Centre of Oncological Hadrontherapy (CNAO). They had recurrence of cervical (5), endometrial (2) and ovarian (1) cancer. Median age at the time of registration for particle RT was 58 years (range:35-72 years), and median GTV was 79 cm 3 (range: 34.99-172.80). Two patients, with marginal lymph node recurrence, were irradiated with protons up to a total dose of 25 GyRBE and 51 GyRBE respectively. The remaining women underwent to carbon-ion radiotherapy (CIRT) with a median total dose of 50.4 GyRBE (range: 36-57) administered in a median number of 12 fractions. Three patients with pelvic side wall recurrences received surgical spacer placement by open surgery to keep intestinal tracts apart from the tumor, since the distance between tumor and nearest intestinal tracts was not sufficient. Toxicity was scored according CTCAE 4.0 scale. Results All patients completed the planned treatment and no acute toxicities G>1 were observed. For the evaluable patients no grade 2 or higher late toxicities were reported. For the patients with a follow-up > 3 months, we observed 1 local recurrence and 5 patients died for systemic progression. The median local control was 10.26 months. Data is still ongoing. Conclusion Although the study's limitations, particle therapy showed no severe toxicities for recurrence of gynecological cancers after RT. Unfortunately, patients with large volume central or pelvic side wall recurrences have poor prognoses therefore efforts should be made to detect pelvic recurrences early. A strong collaboration between Gynecologic Oncologists and Radiation Oncologists is of upmost importance to make a step forward in the treatment of these diseases. Hence, hadrontherapy for pelvic recurrences should be further investigated in a prospective and multicenter trial. EP-1498 Reporting vaginal doses for cervival patients receiving external beam radiotherapy and brachytherapy T. Chan 1 , P.W. Tan 1 , J.I.H. Tang 1 1 The National University Cancer Institute- Singapore NCIS, Radiation Oncology, Singapore, Singapore Purpose or Objective Literature reports an increased incidence of radiation sensitivity to the lower part of the vagina. However, there is still a lack of data on dose delivered to the mid and lower thirds of the vagina. Classically, vaginal dose points are defined at vaginal source level without recording dose information to the entire vaginal vault. To date, reliable vaginal dose volume/surface histograms are unavailable. Hence, this study aims to investigate and report vaginal dose points for combined external beam radiation therapy This abstract is part of the media programme and will be rel ased on the day of its presentation

Results Of the 45 patients treated, 71% were diagnosed with FIGO 2B to FIGO 4A. The mean VRL on CT was 5.1cm. Total Equivalent Dose in 2Gy (EQD2) doses at PIBS -2cm, PIBS - 1cm, PIBS, PIBS +1cm, PIBS +2 cm and PIBS +3cm were 20.2 ± 16.0Gy, 36.8 ± 14.7Gy, 48.6 ± 8.9Gy, 57.9 ± 8.7Gy, 73.0 ± 20.1Gy and 118.9 ± 67.1Gy respectively. When compared to the Caucasian population, all values demonstrated statistical significance. Conclusion Comprehensive vaginal dose reporting using a standard template is feasible. There is large dose variations between patients observed in all parts of the vagina. This results from different contributions from EBRT and BTC. When compared to an all Caucasian population, all values were statistically significant. Moving forward, clinical correlation of toxicities using this vaginal dose point reporting system in cervical cancer patients may be used to estimate and guide treatment toxicity outcomes. EP-1499 The case selection for brachytherapy in cervical cancer patients after radical hysterectomy H. Xu 1 , Y. Lai 2 , Y. Jin 1 1 Ruijin Hospital- Shanghai Jiaotong University School of Medicine, Radiation Oncology, Shanghai, China ; 2 XiaoShan Hospital, Oncology, Zhejiang, China Purpose or Objective To explore the suitable cases for brachytherapy as a component of adjuvant radiotherapy, and analyzed the relapse patterns of cervical cancer patients after radical hysterectomy. Material and Methods We retrospectively analyzed the clinical data of 213 cervical cancer patients (aged 28-78 years) with FIGO stage Ⅰ A to Ⅱ B admitted to our department who received adjuvant radiotherapy from January 2008 to December 2015. Squamous cell carcinoma (178 cases), adenocarcinoma(25 cases), adenosquamous carcinoma (9 cases) and undifferentiated carcinoma (1 case) were