City vs. country: Cancer found at earlier stages in rural patients
■ Better screening for all is urged by researchers in a new study that looked at colorectal and lung cancer.
By Susan J. Landers — Posted Dec. 3, 2007
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Washington -- Who is more likely to seek an early diagnosis for colorectal or lung cancer: a resident of a large city or someone from the country? The authors of a new study were surprised by the answers they found.
Those who live in large cities, surrounded by physicians and hospitals, were less likely to come in for diagnosis and care at an earlier, and possibly curable, stage of disease than were those who lived far from any metropolitan center.
The findings, which appeared in the November Journal of the American College of Surgeons, run counter to the notion that rural cancer patients present at later stages of disease than do those who live in cities, said study authors.
The finding is part of a larger research push to uncover the demographic factors associated with patients delaying care until their cancer has progressed to an advanced stage, said study author Ian Paquette, MD, a surgical resident at Dartmouth-Hitchcock Medical Center in Lebanon, N.H.
There has been research on the impact of race, gender and finances on when people present with late stages of cancer, said Dr. Paquette. "We were trying to take that a step further and see if where patients live has any impact."
A personal interest
As a surgical resident in the rural state of New Hampshire and having been raised in neighboring Maine, Dr. Paquette also had a personal interest in the study's outcome. "A lot of the time we get the rural patient who hasn't seen a doctor in 20 years and comes in with a really late, metastatic cancer that we can't treat."
But rather than finding that scenario exclusively in rural areas, similar situations were occurring even more frequently in cities. "The proportion of urban patients presenting with metastatic cancer is alarming," said Dr. Paquette.
The study highlights the need for better screening efforts for colorectal cancer and the need to develop an effective detection program for people at high risk for lung cancer, he noted.
Although colonoscopies are widely recognized as effective tools for detecting colorectal cancer at early and treatable stages, such screening for lung cancer is still in the future. A large, multisite clinical trial is under way to determine whether screening with a CT scan or standard chest x-ray can detect lung cancer early and make a difference in mortality rates.
The National Lung Screening Test, sponsored by the National Cancer Institute, has enrolled nearly 50,000 current or former smokers at more than 30 sites. Enrollment closed in 2004 and data analysis will be under way for eight years. The trial is randomized and controlled and is considered large enough to determine if there is a 20% or greater drop in lung cancer mortality from using spiral CT compared with chest x-ray.
For their study, Dr. Paquette and co-author Samuel R.G. Finlayson, MD, MPH, associate professor of surgery at Dartmouth-Hitchcock Medical Center, looked at more than 160,000 lung cancer patients and nearly 130,000 colorectal cancer patients identified in the NCI's Surveillance, Epidemiology and End Results, or SEER, database.
That database is the only comprehensive source of population-based information in the nation that includes stage of cancer at the time of diagnosis and patient survival data, the researchers wrote.
Rural versus urban designations were based on codes from the Dept. of Agriculture that classify areas according to population and proximity to a metropolitan area.
They found that urban patients were presenting with later stages of colorectal and lung cancer after controlling for other factors, including age, race, gender, marital status, income and education levels.
Several other demographic differences came into play. For example, rural colorectal cancer patients were older and considerably poorer than their urban counterparts. Urban lung cancer patients were also typically younger and more likely to be African-American than were rural patients.
The study was not able to consider health insurance status because that information was not available in the SEER database, said Dr. Paquette. However, research published in the July 15 Cancer did find that uninsured people and those covered by Medicaid were likely to be diagnosed later and with more advanced cancers than were people who were privately insured. That study looked at patients with breast and oral cavity cancer.