Occupational cancer screening in firefighters: A pilot randomized study of whole-body screening modalities

Background: The International Agency for Research on Cancer has concluded that occupational work as a firefighter is carcinogenic. Given the higher risk of multiple cancer types in firefighters, providing evidence-based preventive health services including recommendations on cancer screening is imperative. Evidence-based data and recommendations on the optimal screening approach for firefighters and understanding risks and benefits of newer screening modalities that firefighters are already receiving in real-world practice, such as whole-body imaging and multi-cancer detection blood (MCD) tests, are limited and needed. This pilot cancer screening trial aims to generate preliminary data on the clinical utility and impact of using whole-body imaging and MCD testing for cancer screening in firefighters, and to evaluate the downstream healthcare utilization and diagnostic testing that results from these screening tools. Methods: Eligibility for this trial includes firefighters in Northern Virginia who are ≥ 35 years old with at least 10 years of service and who have not had cancer within the past 5 years or testing with any of the whole-body screening modalities in the past year. Participants are randomized equally to receive either a whole-body MRI or whole-body ultrasound and all participants receive MCD testing. A validated risk stratification approach (ONCO-RADS) for whole-body MRI screening that evaluates findings based on the likelihood of cancer is used to guide clinical follow-up decisions. Whole-body ultrasound reports are evaluated by a team of clinical investigators to risk stratify findings by organ system as either normal, clinically actionable/not suspicious for cancer, or clinically actionable/suspicious for malignancy. Participants with a positive MCD test undergo a detailed clinical evaluation followed by further diagnostic work-up. After imaging, participants meet with a clinical investigator to review findings and recommended diagnostic follow-up, if warranted. Participants are encouraged to complete age-appropriate standard of care screenings and are offered a total body skin examination along with three-dimensional total-body photography. Those meeting NCCN criteria are offered genetic counseling and testing. Participants are contacted to complete a cancer outcomes survey one year following their imaging. For each screening arm, the number and proportion of confirmed malignancies relative to the number screened will be calculated, as well as other measures of clinical impact such as the proportion of false-positives and an evaluation of the diagnostic follow-up needed. Results from this pilot will support development of a larger trial to evaluate risks and benefits of emerging screening modalities and provide a standardized and evidence-based screening approach for firefighters. Enrollment began in February 2025. Around 450 (of 800 planned) participants have enrolled as of December 2025, with anticipated completion in summer 2026 (NCT06931561).