Calypso Guided High Precision Stereotactic Ablative Radiosurgery for Lung TUmours Using Real-Time Tumour Tracking & Respiratory Gating

Overview

This is a single arm seamless phase I/II prospective cohort study. Patients with early stage Non-Small Cell Lung Cancer (T1-T2N0M0) or those with a single pulmonary metastasis of a known malignancy (either following radical treatment or systemic therapy) will be offered participation in this study. Participants will have three tumor locator beacons placed with a flexible bronchoscope in the small bronchial airways in proximity (\<3cm) from their lung tumors. These tumor locator beacons will provide real-time positional data and will allow for smaller treatment volumes of Stereotactic Ablative Radiosurgery (SABR) and also allow for a specialized form of treatment delivery known as respiratory gated SABR. This is expected to result in higher precision radiotheapy delivery with less radiotherapy dose to healthy tissues which are in close proximity to the lung tumours.

This trial is a seamless phase I/II prospective, single arm, cohort study. Phase I of the trial will consist of two patients and will serve to conduct quality assurance assessments and to familiarize thoracic surgeons, radiation oncologists, and medical physicists at CancerCare Manitoba and Health Sciences Center in the use and work flow of the Health Canada approved endobronchial implanted real-time tumor tracking transponder beacons. Patients in phase I will undergo standard stereotactic ablative radiotherapy (SABR) of a lung tumor with prior endobronchial transponder beacon placement. For phase I, the transponder beacons will be used for comparative localization analyses and SABR treatment setup procedures will be carried out independent of transponder beacon data, however, transponder data will be collected in order to conduct, post-treatment, in vivo quality assurance assessments of beacon performance characteristics. Otherwise, the SABR treatment for phase I will consist of the currently accepted standard internal target volume based and standard image guided SABR. Phase II of this trial will consist of 26 patients who will undergo a specialized form of SABR radiotherapy specifically designed to take full advantage of the real-time tumor tracking ability of the transponder beacons. Specifically, SABR in phase II will consist of smaller radiotherapy treatment volumes employing respiratory gating and smaller planning target volume expansion margins given the superior tumor location telemetry afforded by the beacons. Comparative dosimetric analyses contrasting the traditional ITV/PTV style treatments to those with reduced ITV/PTV margins achieved via Calypso guided SABR will be performed. Patient self-reported quality of life and toxicity assessments will be collected with the goal of facilitating power and sample size calculations for the design of a larger phase III randomized controlled trial of Calypso guided SABR treatment in the future