ESTRO 2022

Session Item

Sunday

May 08

16:55 - 17:55

Room D1

Urology

Co-Chair: Nejla Fourati, Tunisia;

Chair: , Germany

Session Code: 2520

Session Type: Proffered Papers

Track: Clinical

17:35 - 17:45

Radiotherapy quality assurance of the PEACE-1 trial: Initial results of individual case reviews

Najlaa Alyamani, Belgium

Presentation Number: OC-0609

Abstract

Abstract Title:

Radiotherapy quality assurance of the PEACE-1 trial: Initial results of individual case reviews

Authors:

Najlaa Alyamani¹, Paul Sargos², Pierre Blanchard³, Stephane Supiot⁴, Philipe Ronchin⁵, Pascal Pommier⁶, Thomas Duberge⁷, Marlon Silva⁸, Yasser Hammoud⁹, Ali Hasbini¹⁰, Jonathan Khalifa¹¹, Khemara Gnep¹², Christopher Scrase¹³, Jordi Saez¹⁴, Laure Vieillevigne¹⁵, Melissa Christiaens¹⁶, Thomas Zilli¹⁷, Hélène Ribault¹⁸, Alberto Bossi¹⁹, Karim Fizazi²⁰, Nicolaus Andratschke²¹

¹EORTC, RTQA, Brussels, Belgium; ²Institut Bergonie, Department of Radiotherapy, Bordeaux, France; ³Institut Gustave Roussy, University of Paris Saclay, Department of Radiation Oncology, Villejuif, France; ⁴Institut de Cancérologie de l'Ouest - site René Gauducheau, Department of Radiation Oncology, Nantes, France; ⁵Centre Azuréen de Cancérologie, Department of Radiation Oncology, Mougins, France; ⁶Centre Léon Bérard, Department of Radiation Oncology, Lyon, France; ⁷ Croix rouge française, centre saint louis, Department of Radiation Oncology, Toulon, France; ⁸Centre François Baclesse, Department of Radiation Oncology, Caen, France; ⁹CHU Jean-Minjoz, Department of Radiation Oncology, Besançon, France; ¹⁰CFRO-Clinique Pasteur, Department of Radiation Oncology, Brest , France; ¹¹ Institut Claudius Regaud/ Institut Universitaire du Cancer de Toulouse - Oncopole, Department of Radiation Oncology, Toulouse, France; ¹²Centre Eugène Marquis, Department of Radiation Oncology, Rennes , France; ¹³Ipswich Hospital, Department of Oncology, Ipswich, Suffolk, United Kingdom; ¹⁴Hospital Clinic de Barcelona, Radiation Oncology Department, Barcelona, Spain; ¹⁵Institut Claudius Regaud-Institut Universitaire du Cancer de Toulouse, , Department of Medical Physics, Toulouse, France; ¹⁶Universitair Ziekenhuis Leuven, Department of Radiation Oncology, Leuven, Belgium; ¹⁷Geneva University Hospital, Department of Radiation Oncology, Geneva, Swaziland ; ¹⁸UNICANCER, UNICANCER, Caen, France; ¹⁹Institut Gustave Roussy, Department of Radiation Oncology, Villejuif, France; ²⁰Institut Gustave Roussy, University of Paris Saclay, Department of Cancer Medicine, Villejuif, France; ²¹ University Hospital Zurich, University of Zurich, Department of Radiation Oncology, Zurich, Switzerland

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Purpose or Objective

The PEACE-1 trial, sponsored by Unicancer, is a prospective randomized phase 3 study on androgen deprivation therapy (+/- docetaxel) with/without local radiotherapy and with/without abiraterone acetate and prednisone in men with metastatic hormone-naïve prostate cancer (n=1173). Retrospective individual case review (ICR) is an integral part of the radiotherapy quality assurance (RTQA) process in the trial and was provided by RTQA group at the EORTC. This study describes the interim results of ICR for patients accrued in the two radiotherapy arms and assesses the compliance level to the study protocol.

Material and Methods

A total of 59 out of 81 participating institutions have sent their cases anonymized for the extensive central review, 11% of which had their radiotherapy delivered using 3DCRT. Each uploaded DICOM RT plan were reviewed by a radiation oncologist and a medical physicist for protocol compliance of target volume and organs at risks (OARs) delineation, as well as dose specifications. The outcome of the case reviews were classified as acceptable ”A”, acceptable variation “AV”, or unacceptable variation “UV”.

Results

The trial closed for accrual in December 2018. A total of 584 patients were recruited in the radiotherapy arms and 533 complete RT plans were uploaded to the EORTC. To date, 485 (91%) have been reviewed and analyzed. For the delineation review, 64 (13%) cases were unacceptable; specifically, 43 instances of erroneous CTV delineation, 21 instances of erroneous PTV delineation, and 19 instances of missing or improperly delineated OARs were observed.

After excluding the unacceptable delineated cases, 421 cases were reviewed for dose and plan: 401 (95%) of them were either A or AV. Only 19 cases were assigned UV, mainly for insufficient PTV coverage. In 6 cases, dose constraints to OARs were reasons for unacceptable review.

Table-1: Dosimetric results of the interim ICR for OARs

OARs	Protocol dose constraints	Mean observed values (range, SD)
Rectum	V60≤ 50%	16.7% (0 – 50%, 8%)
	V70≤ 25%	7.8% (0 – 27.6%, 5%)
	V74 ≤ 5%	0.8% (0 – 10.7%, 1%)
Bladder	V60≤ 50%	14% (0 – 96%, 11%)
Bladder	V70≤ 25%	0.8% (0 – 85%, 8%)
Femoral heads	V50≤ 10%	1% (0 - 65%, 5%)

Conclusion

RTQA is a critical component in radiotherapy trials. It is reassuring that 82% of the overall review was considered acceptable in PEACE-1. Of the limited number of unacceptable cases, most were due to CTV delineation or PTV coverage issues, while OARs were significantly less affected.