Distance to Treatment Center May Affect Survival for Children and Young Adults with ALL

A study published in Cancer found that among children and young adults with acute lymphoblastic leukemia (ALL), a distance to treatment center greater than 50 miles was associated with inferior overall survival (OS).

However, no difference was observed for patients with acute myeloid leukemia (AML).

“This group represents more than 20% of children and young adults with ALL, and an increase in attention to adherence, supportive care, and logistics for patients living [more than 50] miles from their treatment center is warranted,” the authors wrote. “Further research to determine whether differences in survival are driven by relapse or treatment-related mortality can help to inform which factors (eg, compliance with medication and appointments, caregiver emotional stress, and financial toxicity) should be targeted for intervention.”

Using the National Cancer Database, researchers identified patients 39 years old or younger who were diagnosed with AML or ALL. A backward elimination procedure was then used to select final multivariate Cox models. Notably, the ALL model included distance to treatment center, Charlson-Deyo score, age, race, insurance status, and community income level. The final model for AML included the same variables as the ALL model except for distance to treatment center, which was not statistically significant.

In total, 12,301 patients with AML and 22,683 patients with ALL were included in the study. Among both patient groups, slightly more than 20% had a travel distance greater than 50 miles. For all patients with AML, the 5- and 10-year OS rates were 51% (95% CI, 50%-52%) and 48% (95% CI, 47%-49%), respectively, while for patients with ALL, the 5- and 10-year overall survival rates were 79% (95% CI, 79%-80%) and 76% (95% CI, 75%-77%), respectively.

Compared with distances greater than 50 miles, all other distances were associated with improved survival (HR for ≤10 miles, 0.91; P = .04; HR for >10 to ≤20 miles, 0.86; P = .004; HR for >20 to ≤50 miles, 0.87; P = .005). Specifically, compared with white patients, African Americans, Hispanics/Latinos, and Native Americans had inferior OS, whereas no difference was identified for Asians or those of other races. Moreover, compared with those with private insurance, patients with government insurance or no insurance at diagnosis had inferior survival, and compared with patients with a community median income of $63,000 or more, those with lower median incomes had inferior survival.

No statistically significant interactions were seen with any of the variables; therefore, subgroup analyses were not performed.

“Taken together, these data suggest that the physical distance to the treatment center, as opposed to only the intrinsic community factors, influences overall survival for ALL patients,” the authors wrote. “Additionally, this study adds to the existing literature and uses a larger population to show that multiple socioeconomic factors such as race, insurance status, and income are all associated with survival for children and young adults with acute leukemia.”

Patients received an urban-rural designation based on the zip code of the patient’s address at the time of diagnosis as defined by 2000 US Census data. Similarly, the community median income reflected that of the patient’s zip code, not patient-specific information. Overall, US census definitions of urban and rural were not found to be statistically significant, and no interaction was significant for included variables.

Importantly, because this study was a population-level study, the differences observed between patients with ALL and AML are only hypothesis generating, and the study cannot definitively explain the reason that treatment distance affects outcome.

Reference:

Rotz SJ, Wei W, Thomas SM, Hanna R. Distance to Treatment Center Is Associated With Survival in Children and young Adults with Acute Lymphoblastic Leukemia. Cancer. doi: 10.1002/cncr.33175