Centralized Quality Assurance of Stereotactic Body Radiation Therapy for the Veterans Affairs Cooperative Studies Program Study Number 2005: A Phase 3 Randomized Trial of Lung Cancer Surgery or Stereotactic Radiotherapy for Operable Early-Stage Non-Small Cell Lung Cancer (VALOR).

Abstract

Background: The phase III Veterans Affairs Lung cancer surgery Or stereotactic Radiotherapy (VALOR) study implemented centralized quality assurance (QA) to mitigate risks of protocol deviations. This report summarizes quality and compliance for the first 100 participants treated with SBRT in this study.

Methods: A centralized QA program was developed to credential and monitor study sites to ensure standard-of-care lung stereotactic body radiation therapy (SBRT) treatments are delivered to participants. Requirements were adapted from protocols established by the National Cancer Institute's Image and Radiation Oncology Core, which provides oversight for clinical trials sponsored by the NCI's National Clinical Trials Network.

Results: The first 100 lung SBRT treatment plans were reviewed from April 2017 to October 2022. Tumor contours were appropriate in all submissions. PTV expansions were less than the minimum 5 mm requirement in 2% of cases. Critical organ-at-risk (OAR) structures were contoured accurately for the proximal bronchial tree, trachea, esophagus, spinal cord, and brachial plexus in 75%, 92%, 100%, 100%, and 95% of cases. Prescriptions were appropriate in 98% of cases; two central tumors were treated using a peripheral tumor dose prescription while meeting OAR constraints. PTV V100% values were above the protocol-defined minimum of 94% in all but one submission. The median Dmax within the PTV was 125.4% (105.8% - 149.0%, standard deviation ±8.7%). High-dose conformality (<1.2) and intermediate-dose compactness (R50% and D2cm) indices were acceptable or deviation acceptable in 100% and 94% of cases, respectively.

Conclusions: The first 100 participants randomized to SBRT in this study were appropriately treated without safety concerns. A response to the incorrect prescriptions led to preventative measures without further recurrences. The program was developed in a healthcare system without prior experience with a centralized RT QA program and may serve as a reference for other institutions.