ESTRO 36 Abstract Book

S139 ESTRO 36 _______________________________________________________________________________________________

Results Median age is 69 (19, 26 and 31.5 Gy), 70 (20 Gy), 68 (34 Gy) and 67 years (36 Gy). For 19, 20, 26, 31.5, 34 and 36 Gy median PSA was 8.2, 10.7, 11, 12.4 11.1 and 10.5 µg/l, Gleason Scores ≥ 8 were 4%, 31%, 11%, 6%, 11% and 13%, proportion with T 3 disease was seen in 29%, 35%, 32%, 36%, 43% and 35% of patients, and median follow-up 54, 48, 62, 107, 129 and 121 months, respectively. Neo-adjuvant and adjuvant androgen deprivation treatment was given to 76% of all patients; intermediate risk patients were treated for 6 months and high risk for up to 3 years. K-M estimates of FFbR, DFS and OS and p

The non-parametric Wilcoxon and Spearman tests were used to estimate the relationships. The data were analyzed using SPSS version 22. Results The gross tumor volume (GTV-t) was greater by FDG- PET/CT-simulation but differences were not statistically significant. However, the gross node volume (GTV-n) and the length of the esophageal tumor were greater by FDG- PET/CT-simulation and these differences were statistically significant ( Table 1 ). The analyzed of DSC showed a great similarity of GTV-t: 0.71 (0.13). A very low DSC was observed in GTV-n: 0.08 (0.47). Data are expressed as median and inter-quantile range. Values greater than 0.7 are often regarded as an excellent agreement. Correlations between volume sizes for PET/CT and CT were determined using a correlation coefficient. There was a very high correlation ( 0.82 ) between CT and FDG- PET/CT simulation (p=0.002) in the GTV-tumor volumes. However, this correlation was very low (0.58) in the GTV- node (p=0.01) and length of the esophageal tumor (0.67, p=0.001).

Conclusion The results indicate that large doses per fraction of high- dose-rate brachytherapy are feasible and late adverse events manageable. The incidence of severe urinary and IPSS scores events is similar for all groups with no significant difference in PSA control for single-dose versus 2 to 4 fractions of HDF-BT at this relatively early stage. Whilst longer follow up is required a large single dose of HDR brachytherapy appears both safe and effective.

Conclusion Our study shows that the volume definition by FDG- PET/CT and CT simulation in esophageal cancer differs, especially with respect to GTV-node volume and tumor length. FDG-PET/CT appears to have an impact on treatment planning and management of esophageal carcinoma.

Proffered Papers: Prostate 2

OC-0270 QoL and toxicity of HDR prostate brachytherapy as monotherapy 19Gy single fraction:phase II trial

OC-0269 Single Dose Compared to Fractionated High- Dose Rate Brachytherapy for Localised Prostate Cancer P. Hoskin 1 , A. Rojas 1 , P. Ostler 1 , R. Hughes 1 , R. Alonzi 1 , G. Lowe 1 1 Mount Vernon Hospital, Cancer Centre, Northwood Middlesex, United Kingdom Purpose or Objective To evaluate late toxicity and freedom from biochemical relapse (FFbR) after high-dose-rate brachytherapy (HDR- BT) in localised prostate cancer. Material and Methods HDR-BT delivering 1 x 19 Gy, 1 x 20 Gy, 2 x 13 Gy, 3 x 10.5 Gy, 4 x 8.5 Gy and 4 x 9 Gy was given to patients with predominantly intermediate or high-risk prostate cancer. All patients were staged with at least pelvic MR and isotope bone scan to exclude metastatic disease. Transperineal-transrectal ultrasound guided implantation was followed by MR based CTV definition following the GEC ESTRO guidelines. Biochemical relapse was assessed using the Phœnix definition (PSA nadir plus 2 µg/L). Late urinary (GU) and gastrointestinal (GI) were assessed using the RTOG and the International Prostate Symptom Score (IPSS). Patients were evaluated prospectively from 6 months after implant and bi-annually thereafter. Pearson’s Chi-square was used to test for significance between prevalence of GI, GU catheter use and IPSS events. Estimates of freedom from biochemical relapse, disease-free survival (DFS) and overall survival (OS) and of GI, GU and IPSS toxicity were calculated using the Kaplan- Meier (K-M) method and the log-rank test to test for significance.

A. Gomez-Iturriaga 1,2 , F. Casquero 1 , P. Minguez 1 , J. Espinosa 1 , A. Bueso 1 , J. Cacicedo 1 , L. Fernandez 1 , S. Pedraza 1 , J. Garcia Escovedo 1 , P. Bilbao 1 1 Hospital de Cruces, Oncologia-Radioterapia, Baracaldo- Vizcaya, Spain 2 Biocruces Health Research Institute, Radiation Oncology, Barakaldo, Spain Purpose or Objective High-dose rate brachytherapy (HDR-BT) is an advanced technology theorized to be more advantageous than Low Dose Rate-BT (seeds) and External Beam Radiotherapy (EBRT), to the patient himself, and in terms of resource consumption. Evidence supports the use of HDR-BRT as monotherapy for selected patients with low- and intermediate-risk prostate cancer when administered in 4 or more fractions. There is limited data on the safety and efficacy of HDR given in a single fraction. The primary endpoint of this study is to evaluate the safety, tolerance and impact on quality of life (QoL) of the BT-HDR 19Gy administered in single fraction in patients with low and intermediate risk prostate cancer. Secondary endpoint is to measure the efficacy, in terms of cancer control and satisfaction of the patients undergoing the experimental treatment. Material and Methods From January 2014 to July 2016, 43 consecutive patients have been treated with HDR-BT 19Gy administered in a single fraction. Eligible patients had low or intermediate- risk prostate cancer; IPSS lower than 15; prostate volume