Looking at national data on those two types of cancer, the study found that urban patients tend to be diagnosed at a later stage than their rural counterparts—even when the study controlled for other factors associated with late-stage presentation, such as age, race, gender, marital status, income level, and level of education.

The paper, "Rural Versus Urban Colorectal and Lung Cancer Patients: Differences in Stage at Presentation," was published in the November 2007 Journal of the American College of Surgeons. The authors are Ian Paquette, a general surgery resident at the Dartmouth-Hitchcock Medical Center (DHMC), and Sam Finlayson, a DHMC surgeon and vice chair for academic affairs for the Department of Surgery of the Dartmouth Medical School.

The team's findings fly in the face of the anecdotal evidence, including the sorts of tales traded in the corridors of DHMC, which serves a rural slice of New Hampshire and Vermont. "Where we practice, most doctors can tell stories about patients who have presented at a very late stage of a disease, and we find it hard to imagine that they could have ignored their symptoms for so long," said Paquette.

Knowing which types of patients are more likely to present with more advanced cancers helps doctors better implement screening efforts, allowing them to diagnose patients at earlier stages and improve their prognoses, said Paquette. The study focused on colorectal and lung cancer because these are types that surgeons see frequently in their day-to-day practice.

The team looked at more than 125,000 people with colorectal cancer and more than 160,000 people with lung cancer, drawing on 2000-03 data from the National Cancer Institute's Surveillance, Epidemiology, and End Results database, which collects data on many different types of cancer from 18 states. They used the rural-urban continuum codes from the US Department of Agriculture to analyze the data as to whether patients lived in rural or urban areas.

Source: Dartmouth College