ESTRO 2022 - Abstract Book

S1194

Abstract book

ESTRO 2022

1 Odette Cancer Centre, Sunnybrook Health Sciences Centre, Radiation Oncology, Toronto, Canada; 2 Molli Surgical, Medical Devices, Toronto, Canada; 3 Princess Margaret Cancer Centre, Radiation Oncology, Toronto, Canada; 4 King Saud University, Radiation Oncology, College of Medicine, Riyadh, Saudi Arabia Purpose or Objective Contemporary radiotherapy for localized prostate cancer (PCa) is deliverable via stereotactic ablative radiotherapy (SABR) and high dose rate (HDR) brachytherapy. Here we report on a parallel cohort analysis of two prospective, phase II clinical trials of two-fraction prostate SABR versus two-fraction HDR monotherapy. Materials and Methods Enrolled patients had histologically-confirmed PCa (clinical stage T1c-T2b; grade group 1, 2, or 3; and PSA <20 ng/mL). SABR and HDR doses were 26 Gy and 27 Gy in 2 weekly fractions, respectively. Patient-level data from each cohort was analysed to assess prostate specific antigen (PSA) response kinetics, biochemical failure, toxicity, and quality of life (QOL). Results Thirty patients receiving SABR and 83 receiving HDR were included. Fifty percent and 30% of patients had unfavourable- intermediate risk disease, respectively. SABR patients had higher mean baseline PSA (8.7 versus 6.8 ng/mL, p=0.016). Median follow-up was 72.7 and 65.3 months, respectively. Mean dose delivered to the prostate (Dmean) ranged from 26.6 to 26.8 Gy for SABR versus 35.5 to 45.5 Gy for HDR. Both cohorts achieved a median nadir PSA of 0.16 ng/mL at a median of 57 months post-treatment. Nine patients in total experienced biochemical failure, 1 following SABR (3.3%) and 8 following HDR (9.6%). Cumulative BF probability (±SE) at 72 months was 3.5% (±3.5%) for SABR versus 12.8% (±4.8%) and was not significantly different between cohorts (p=0.19). Low rates of CTCAE grade ≥ 2 toxicity were observed in both cohorts. No differences in EPIC scores over time were observed between cohorts. Conclusion Two fractions of SABR yields similar rates of biochemical failure, acute and late toxicities, and QOL as two factions of HDR brachytherapy. These hypothesis-generating data support the design of a randomized controlled trial to test a two-fraction SABR versus two-fraction HDR monotherapy. 1 University Hospital of Besançon, Radiation Oncology, Besançon, France; 2 Centre Georges François Leclerc, Radiation Oncology, Dijon, France; 3 Centre Georges François Leclerc, Statistics, Dijon, France; 4 Hôpital Nord Franche-Comté, Radiation Oncology, Montbéliard, France; 5 Institut Curie, Radiation Oncology, Paris, France Purpose or Objective The role of inflammation in the development of bladder cancer is now established. We wanted to evaluate the significance of inflammatory markers such as neutrophil-to-lymphocyte ratio (NLR) and neutrophil count in patients with localized muscle-invasive bladder cancer (MIBC) treated with chemoradiation (CRT). Materials and Methods Patients treated between 1996 and 2019 with curative CRT for non-metastatic MIBC were retrospectively included. Clinical and treatment characteristics, baseline biological data (including NLR, and neutrophils counts(PNN)), acute and late toxicities were recorded. Local and metastatic recurrences, overall survival (OS) and progression-free survival (PFS) were evaluated. We tested the association between NLR, PNN, and survival outcomes. We used median values as cut-off for statistical analysis. Results Two hundred and four patients were included. Median age at diagnosis was 79.0 years [55.0 – 94.0] and median follow-up was 41.3 months [1.0 – 243.5]. Local and metastatic recurrences occurred in 29 patients (17%) and 60 patients (36%), respectively. The 4-year OS and PFS rates were 46% [37.5% – 54.4%] and 28.9% [21.7% – 36.5%], respectively. There was significantly more hydronephrosis in the high NLR (>2.6) group (41% vs 24%, p=0.02). Median OS was significantly lower in patients with NLR>2.6 compared to patients with NLR ≤ 2.6 (24.1 months [18.6 – 40.6] vs 56.8 months [42.7 – 96.8], p=0.006) (Fig 1). Median OS was significantly lower in patients with PNN > 4000/mm 3 compared to patients with PNN ≤ 4000/mm 3 (24.1 months [14.1 – 30.5] vs 70.1 months [52.4 –], p<0.001). By univariate analysis, T3-T4 stage (HR=1.97, 95%CI [1.22–3.17]; p=0.005), hydronephrosis (HR=1.69, 95%CI [1.11 – 2.58], p=0.02), PNN >4000/mm 3 (HR=2.74, 95%CI [1.77 – 4.24], p<0.001), and NLR>2.6 (HR=1.77, 95%CI [1.17 – 2.67], p=0.007) were significantly associated with shorter OS. By multivariate analysis, only PNN>4000/mm 3 was significantly associated with shorter OS (HR=2.95, 95%CI [1.67 – 5.21], p<0.001). Median PFS was significantly lower in patients with NLR>2.6 compared to patients with NLR<2.6 (13.1 months [9.6 – 21.8] vs 26.7 months [15.9 – 44.7], p=0.03) (Fig 2). Median PFS was significantly lower in patients with PNN > 4000/mm 3 compared to patients with PNN ≤ 4000 (12.7 months [8.0 – 19.0] vs 38.8 months [18.6 – 96.8], p<0.001). By univariate analysis, T3-T4 stage (HR=1.95, 95%CI [1.27 – 3.01], p=0.002), hydronephrosis (HR=1.83, 95%CI [1.27 – 2.65], p=0.001), PNN >4000/mm 3 (HR=2.10, 95%CI [1.45 – 3.04], p<0.001) and NLR >2.6 (HR=1.49, 95%CI [1.04 – 2.13], p=0.03) were significantly associated with shorter PFS. By multivariate analysis, only PNN>4000/ mm 3 was significantly associated with shorter PFS (HR=1.79, 95%CI [1.12 – 2.85], p=0.015). PO-1409 Baseline NLR and neutrophil in patients with bladder cancer treated with chemoradiation J. Boustani 1,1 , S. Meunier 2 , J. Blanc 3 , E. Martin 2 , M. Quivrin 2 , S. Benhmida 1 , Y. Hammoud 4 , G. Créhange 5