Regardless of residence, nearly 25% of patients with cancer overall miss at least 10% of the doses in their radiation treatment plans—but the implications on outcomes are far greater for patients living in rural areas than their urban counterparts, according to new research findings published in the International Journal of Radiation Oncology, Biology, Physics.

To assess for geographic disparities and identify sociodemographic and clinical factors contributing to radiation therapy adherence and survival, the nurse scientist–led research team examined cancer registry, medical records, and billing claims data at a safety net academic medical center for 3,077 patients with cancer. After a median 4.5 years of follow-up, the researchers found that despite missing a comparable number of radiation doses, rural patients experienced a higher mortality rate than nonrural patients (53% versus 42%, respectively).

“Specifically, patients residing in rural areas who experienced a treatment delay were more than twice as likely to die as nonrural residents who also experienced a treatment delay, and nearly twice as likely to die as rural residents who did not experience a treatment delay,” the researchers reported.

The two-year survival rate was 76% for nonrural residents who did not experience a treatment delay versus 27% for rural residents who experienced a treatment delay—and the latter group was also more likely to subsequently be nonadherent. Patients who were widowed or had stage IV cancer or lung cancer were also more likely to be nonadherent.

In addition to implementing nonadherence risk assessments to understand access barriers for each patient based on geographic considerations as well as other factors, the researchers advised routinely recruiting subspecialty nursing roles such as navigators and consulting with other interprofessional cancer care team members, such as social work or financial counselors, to support treatment adherence, particularly for rural patients with radiation treatment delays.

“Radiation therapy nonadherence is a significant concern that affects survival, yet it is a modifiable risk factor,” the researchers concluded. “We demonstrated that rural residence was associated with both radiation therapy nonadherence and poorer overall survival. Rural patients with a treatment delay had the lowest overall survival compared with both nonrural survivors and rural survivors without delay. They are at heightened risk for poor outcomes and should receive targeted support to mitigate disparities.”