ESTRO 2022 - Abstract Book

S186

Abstract book

ESTRO 2022

1 Hôpital Tenon, APHP, Radiation Oncology, Paris, France; 2 Hôpital Saint-Louis, APHP, Radiation Oncology, Paris, France; 3 Fédération francophone de cancérologie digestive (FFCD), Biostatistics department, Dijon, France; 4 Centre Antoine Lacassagne, Medical Oncology, Nice, France; 5 Institut du Cancer de Montpellier, Radiation Oncology, Montpellier, France; 6 Groupe Hospitalier Paris Saint Joseph, Medical Oncology, Paris, France; 7 Centre Léon Bérard, Radiation Oncology, Lyon, France; 8 CHU de Rennes, Gastroenterology, Rennes, France; 9 CHU de Poitiers, Gastroenterology, Poitiers, France; 10 CHD- Vendée, Gastroenterology, La Roche sur Yon, France; 11 Institut de Cancérologie Paris Nord, Radiation Oncology, Paris, France; 12 Groupe Hospitalier Mutualiste de Grenoble, Radiation Oncology, Grenoble, France; 13 Hôpital Foch, Hospital- Office Network Val de Seine, Paris, France; 14 Hôpital Lyon Sud, Radiation Oncology, Lyon, France; 15 Centre Hospitalier de Meaux, Hepato-gastroenterology, Meaux, France; 16 Institut Curie, Radiation Oncology, Paris, France; 17 CHU Bordeaux, Radiation Oncology, Bordeaux, France Purpose or Objective Squamous cell carcinoma of anal canal (SCCAC) is a rare cancer, but frequently associated with HIV infection. We aim to compare clinical outcomes and tolerance according to HIV status in patients with SCCAC treated with modern (chemo)radiotherapy. Materials and Methods This is a subgroup analysis of the SCCAC ANABASE multicentric cohort conducted by the Fédération Francophone de Cancérologie Digestive in 60 French centers. Data were collected both prospectively and retrospectively. HIV-positive patients were compared to HIV-negative patients. Clinical outcomes including overall survival (OS), response rate (RR), locoregional recurrence-free survival (LRFS), relapse-free survival (RFS), colostomy-free survival (CFS), cancer specific survival (CSS), severe acute and late toxicity (grade ≥ 3) were evaluated. Prognostic factors were explored using Cox regression model. Results Between January 2015 and April 2020, 1097 patients with localized SCCAC (stage I, II, III) and treated with (chemo)radiation were included. Only the 488 patients with known HIV status were included in our analysis (86 HIV-positive patients and 402 HIV-negative patients). Median follow-up was 35.8 months. HIV-positive patients were younger (median age of 57 vs 64 years in HIV-positive and HIV-negative patients, respectively, p<0.01) and predominantly male (77% vs 23%, p<0.01). Initial tumor characteristics were similar in both groups (T stage, p=0.32 and N stage, p=0.54). Most of patients received Intensity-Modulated Radiation Therapy (IMRT, 80.7%) and concurrent chemotherapy (80.9%).

OS

CSS

RFS

LRFS

CFS

71.6% [59.0 ; 81.0] 85.1% [80.2 ; 88.8]

83.6% [71.4 ; 90.9] 90.8% [86.7 ; 93.7]

61.5% [48.9 ; 71.9] 74.7% [69.4 ; 79.3] 1.5 [0.98 ; 2.3]

65.3% [53.1 ; 75.0] 78.6% [73.5 ; 82.8] 1.7 |1.1 ; 2.7]

60.4% [47.8 ; 70.9] 76.2% [70.9 ; 80.7]

HIV-positive At 3 years [CI 95%]

HIV-negative At 3 years [CI 95%]

Hazard-Ratio [CI 95%] 2.1

1.7 [0.8 ; 3.5]

1.7 [1.1 ; 2.6]

[1.2 ; 3.5]

p-value

0.007

0.14

0.06

0.02

0.01

OS, LRFS and CFS were significantly lower in HIV-positive patients (Table 1). HIV-positive patients relapsed mostly locally or locoregionally (91.7% of HIV-positive patients with a recurrence), whereas recurrences in HIV-negative patients were mainly metastatic (52.7% of HIV-negative patients with a recurrence, p=0.002). Treatment compliance was similar and no more break or severe toxicities were reported among HIV-positive patients (47.7% grade ≥ 3 acute toxicities in HIV-positive patients vs 45.5% in HIV-negative patients, p=0.65). Only WHO performance status ≥ 1 was associated with decreased OS in multivariate analysis. WHO status was also associated, as well as T3-4 stages (compared with T1-2 stages), with lower RFS, LRFS and CFS. Conclusion HIV-positive patients treated by (chemo)radiation for localized SCCAC had a poorer overall survival than HIV-negative patients, as well as poorer locoregional recurrence-free and colostomy free survivals. Treatment toxicity was not increased in HIV-positive patients with modern IMRT techniques.

Poster Discussion: 05: Intra-fraction & real-time adaptation

PD-0227 reconstructing the dosimetric impact of intra-fractional prostate motion in MR-guided radiotherapy

Y. Xiong 1 , M. Rabe 2 , L. Nierer 2 , S. Corradini 2 , C. Belka 2,3 , M. Riboldi 4 , G. Landry 2 , C. Kurz 2

1 Univerisity Hospital LMU, Department of Radiation Oncology, Munich, Germany; 2 University Hospital LMU, Department of Radiation Oncology, Munich, Germany; 3 German Cancer Consortium (DKTK), Partner Site Munich, Munich, Germany; 4 LMU Munich, Department of Medical Physics, Munich, Germany Purpose or Objective This study aimed at evaluating the intra-fractional prostate motion captured during MR-guided radiotherapy of prostate cancer and analyzing its impact on the delivered dose over all treatment fractions.

Materials and Methods