The Relationship Between Travel Distance for Treatment and Outcomes in Patients Undergoing Radiation Therapy: A Systematic Review.

Purpose: Although recent technological advances in radiation therapy have significantly improved treatment outcomes, the global distribution of radiation therapy is unbalanced, making access especially challenging for patients in rural or low-resource settings because of travel burden. This systematic review aimed to explore the impact of geographic distance to treatment facilities on survival, as well as other treatment outcomes, among patients undergoing radiation therapy. Methods and Materials: A search of four databases (PubMed, Embase, CINAHL, and Web of Science) was performed. Studies were included if they were primary literature, published between May 2000 and May 2023, and reported the travel distances for patients undergoing radiation therapy for malignant conditions and its influence on survival outcomes. Studies were excluded if they did not report primary outcomes, were published before 2000, or were non-English. Results: After review, 23 studies were included. Most studies were conducted in the United States, with cervical cancer being the most frequently studied disease site. Data suggested that travel distances vary significantly, with patients often traveling a median distance of 20 miles to radiation therapy. Among the studies, 5 reported a negative impact on overall survival, often associating greater travel with nonadherence to recommended care. Other survival metrics, including progression-free survival and all-cause mortality, were also assessed, demonstrating similar variability in relation to travel distance. Conversely, seven studies found no significant impact on overall survival, and four suggested a positive impact on overall survival, with improved outcomes at centers with higher case volumes. Some data also revealed an inverse correlation between travel distance and the likelihood of receiving guideline-concordant radiation therapy. Conclusions: The impact of travel distance on radiation therapy outcomes is varied. Our findings underscore the challenges posed by travel in accessing radiation therapy and the disparities affecting particular patient demographic groups. Additional studies are needed to thoroughly assess the impacts of geographic disparities and to identify effective measures to address these challenges.