Some southern states show almost no improvement.
Study points to increased need for screening.
Poverty and uninsured rates are higher in southern states.
PHILADELPHIA - Improvements in colorectal cancer mortality rates are concentrated in the northern part of the United States, while southern states continue to fall behind, according to a report in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Ahmedin Jemal, D.V.M., Ph.D., vice president for surveillance research at the American Cancer Society, said the decrease in death rates ranged from about 37 percent in Massachusetts to no reduction in Mississippi.
"This was very surprising, because when you look at the differences in reductions by state they are huge," said Jemal.
Although colorectal cancer remains the third leading cause of cancer mortality for men and women, rates have been declining nationwide for several decades. The researchers analyzed the temporal trend in age-standardized colorectal cancer death rates for each state from 1990 to 2007.
Overall, states in the South had a lower reduction in mortality than states in the North. The researchers found a strong correlation between higher rates of screening and higher reductions in rates of mortality by state. They speculate that economic disparities may be playing a role in rates of screening. In Mississippi, 18.8 percent of people do not have health insurance, compared with 5.4 percent in Massachusetts. More than 20 percent of the population of Mississippi lives below the poverty line, compared with a national average of 13 percent.
Elizabeth Jacobs, Ph.D., an associate professor of epidemiology and biostatistics at the University of Arizona, said the report shows a significant change in historical trends.
"It used to be that the highest rates of colorectal cancer mortality were in the northeastern part of the United States, but now weve really seen a switch," said Jacobs, an editorial board member of Cancer Epidemiology, Biomarkers & Prevention. "It shows the importance of access to screening."
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The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, the AACR is the worlds oldest and largest professional organization dedicated to advancing cancer research. The membership includes 33,000 basic, translational and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 90 other countries. The AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants, research fellowships and career development awards. The AACR Annual Meeting attracts more than 18,000 participants who share the latest discoveries and developments in the field. Special conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment and patient care. Including Cancer Discovery, the AACR publishes seven major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; Cancer Epidemiology, Biomarkers & Prevention; and Cancer Prevention Research. AACR journals represented 20 percent of the market share of total citations in 2009. The AACR also publishes CR, a magazine for cancer survivors and their families, patient advocates, physicians and scientists.