Breath-Hold Technique for Pancreatic Stereotactic Body Radiation Therapy (SBRT) Patients

Pancreatic cancer (PCa) is a devastating diagnosis with one of the lowest 5-year overall survival rates of all malignancies. It is estimated that at least 45,000 Americans will die of this disease in 2019, making it the third most common cause of oncologic death. Of the patients that present without evidence of distant spread at the time of diagnosis, only a minority of patients are able to proceed directly to surgical resection which remains the mainstay treatment modality. Historical outcomes show that 30-40% of patients present with borderline resectable (BRPC) or locally advanced (LAPC) disease due to tumor involvement of local vasculature which prevents the patients from proceeding directly to surgery. In this context, neoadjuvant therapy with radiation is often administered in an attempt to downstage tumors prior to surgery, reduce the risk of a margin positive failure, and reduce the risk of local recurrence after surgery. For patients who are truly technically or medically unresectable, radiation can be offered with the intent of providing durable local control. Indeed, a recent autopsy study showed that 30 % of patients who expire from PCa do so due to the locally destructive spread from this disease, highlighting the imperative need for an optimal local control strategy.

Delivering radiation to the pancreas is technically challenging and must be carefully delivered given the risk of injury to radiosensitive organs at risk (OAR) in close proximity such as the bowel and stomach. Compounding this difficulty is the variation in positioning of the tumor and OARs due to respiratory induced motion and variation in bowel gas patterns. To achieve daily accuracy in tumor localization, the investigators employ a comprehensive strategy including strict immobilization, endoscopically placed fiducials, and daily on-board cone beam CT (CBCT). Moreover, the investigators utilize active breathing control (ABC), which requires patients to reproducibly perform multiple deep-inspiratory breath holds during treatment. Radiation to the pancreas is delivered only when the patient is holding patient's breath. During ABC, patients breathe through a snorkel-like device that records the volume of air inhaled during each breath. In this apparatus is a valve that will cut off the flow of air once the inhalation volume passes a certain threshold to ensure the same amount of volume is taken in each time a breath hold is performed. Patients are asked to press on a button to start the recording aspect of the device and then to take a deep breath hold. Once patients reach the desired threshold for the inhaled volume, the valve prevents any further air from being inhaled in, and the patient is asked to hold patient's breath for a duration of 20 - 30 seconds. The treatment team is not present in the room with the patient because of radiation exposure so it requires the patient to follow a series of with the treatment team over an intercom system. Patients are asked to do this without any visual biophysical feedback of patient's waveforms, and to do this repeatedly for multiple times per treatment session. The series of instructions can be challenging for many patients, potentially leading to prolonged treatment times and additional breath holds especially in the early fractions before patients become more familiar with the system. Furthermore, with only one planning session to become acquainted with the ABC device and treatment instructions, patients have limited practical time to gain mastery before returning for patient's actual treatment sessions. This is of concern since patients who struggle with the ABC technique may have less consistent reproducibility of daily tumor positioning which may lead to poorer radiation treatment outcomes.

The Investigator proposes the development of an extended reality (xR) training platform for patients undergoing radiation treatment for pancreatic cancer. The Investigator wants to investigate the ability of this technology to provide biophysical feedback and coaching during the planning and treatment sessions to help patients with the ABC technique to improve motion management outcomes and reduce treatment related anxiety.