New research suggests that better access to quality care may reduce disparities in survival between cancer patients living in rural areas of the US and those living in urban areas.
The study showed that urban and rural cancer patients had similar survival outcomes when they were enrolled in clinical trials.
These results, published in JAMA Network Open, cast new light on decades of research showing that cancer patients living in rural areas don’t live as long as urban cancer patients.
“These findings were a surprise, since we thought we might find the same disparities others had found,” said study author Joseph Unger, PhD, of Fred Hutchinson Cancer Research Center in Seattle, Washington.
“But clinical trials are a key difference here. In trials, patients are uniformly assessed, treated, and followed under a strict, guideline-driven protocol. This suggests that giving people with cancer access to uniform treatment strategies could help resolve the disparities in outcomes that we see between rural and urban patients.”
Dr Unger and his colleagues studied data on 36,995 patients who were enrolled in 44 phase 3 or phase 2/3 SWOG trials from 1986 through 2012. All 50 states were represented.
Patients had 17 different cancer types, including acute myeloid leukemia (AML), non-Hodgkin lymphoma (NHL), and multiple myeloma (MM).
Using US Department of Agriculture population classifications known as Rural-Urban Continuum Codes, the researchers categorized the patients as either rural or urban and analyzed their outcomes.
A minority of patients (19.4%, n=7184) were from rural locations. They were significantly more likely than urban patients to be 65 or older (P<0.001) and significantly less likely to be black (vs all other races; P<0.001).
However, there was no significant between-group difference in sex (P=0.53), and all major US geographic regions (West, Midwest, South, and Northeast) were represented.
The researchers limited their analysis of survival to the first 5 years after trial enrollment to emphasize outcomes related to cancer and its treatment. They looked at overall survival (OS) as well as cancer-specific survival.
The team found no meaningful difference in OS or cancer-specific survival between rural and urban patients for 16 of the 17 cancer types.
The exception was estrogen receptor-negative, progesterone receptor-negative breast cancer. Rural patients with this cancer didn’t live as long as their urban counterparts. The hazard ratio (HR) was 1.27 (95% CI, 1.06-1.51; P=0.008) for OS and 1.26 (95% CI, 1.04-1.52; P=0.02) for cancer-specific survival.
The researchers believe this finding could be attributed to a few factors, including timely access to follow-up chemotherapy after patients’ first round of cancer treatment.
Although there were no significant survival differences for patients with hematologic malignancies, rural patients had slightly better OS if they had advanced indolent NHL or AML but slightly worse OS if they had MM or advanced aggressive NHL. The HRs were as follows:
- Advanced indolent NHL—HR=0.91 (95% CI, 0.64-1.29; P=0.60)
- AML—HR=0.94 (95% CI, 0.83-1.06; P=0.29)
- MM—HR=1.05 (95% CI, 0.93-1.18, P=0.46)
- Advanced aggressive NHL—HR=1.05 (95% CI, 0.87-1.27; P=0.60).
Rural patients had slightly better cancer-specific survival if they had advanced indolent NHL but slightly worse cancer-specific survival if they had AML, MM, or advanced aggressive NHL. The HRs were as follows:
- Advanced indolent NHL—HR=0.98 (95% CI, 0.66-1.45; P=0.90)
- AML—HR=1.01 (95% CI, 0.86-1.20; P=0.87)
- MM—HR=1.04 (95% CI, 0.90-1.20; P=0.60)
- Advanced aggressive NHL—HR=1.08 (95% CI, 0.87-1.34; P=0.50).
The researchers said these findings suggest it is access to care, and not other characteristics, that drive the survival disparities typically observed between urban and rural cancer patients.
“If people diagnosed with cancer, regardless of where they live, receive similar care and have similar outcomes, then a reasonable inference is that the best way to improve outcomes for rural patients is to improve their access to quality care,” Dr Unger said.
This research was supported by the National Cancer Institute and the HOPE Foundation. The researchers reported financial relationships with various pharmaceutical companies.