"Primary care physicians are the number one way in which cancer screening is done," says study co-author Richard Roetzheim, MD, MSPH, associate professor of family medicine at the University of South Florida (USF). Roetzheim also practices at the H. Lee Moffitt Cancer Center and Research Institute in Tampa.

"The primary care physician is responsible for the patient''s total health," Roetzheim says, "not just a single symptom or one part of the body. If a patient primarily uses specialist care, there may be no one to look at their overall health."

The USF group looked at all 11,740 cases of breast cancer reported in Florida in 1994, the last year for which complete data were available. They compared the stage of every cancer when it was diagnosed, the degree to which it had spread from the original site, with the supply of physicians for the county in which each patient lived.

Statewide, 71% of breast cancers were diagnosed at an early stage. There was no relationship between the total number of physicians and the stage at which breast cancers were diagnosed. But for every 10% increase in the number of primary care physicians compared to specialty physicians, patients were 4% more likely to get an early diagnosis.

Women in counties with the highest percentage of primary care physicians were 37% more likely to get an early diagnosis. Women in areas with the fewest primary care physicians were no more likely to be diagnosed early than women who had no health insurance coverage, and presumably received little or no preventative care.

"We were surprised at the magnitude of the finding," Roetzheim says. "The results tell us we need to make sure that patients have access to primary care physicians. Somebody has to look at their overall health."

Roetzheim says the better odds of early breast cancer detection are probably due to the high rate at which primary care physicians recommend mammograms. According to other studies, 87% of mammograms are recommended by primary care physicians.

Early detection of breast cancer can save lives, reduce treatment, and improve quality of life, according to the American Cancer Society (ACS). The ACS estimates that 192,200 women will be diagnosed with breast cancer this year, and 40,200 are expected to die from the disease. Among women whose cancer is diagnosed at an early stage, while it is still localized in the breast, more than 96% live five years or longer. Among women whose breast cancer is diagnosed at late stage, after it has spread to distant parts of the body, the five-year survival rate is just 21.3%.

"The number one reason women don''t get mammograms is because their physician doesn''t tell them to do it," says Debbie Saslow, PhD, ACS director of breast and cervical cancer. "We always advocate for women to get breast cancer screening. If a woman''s physician doesn''t refer for a mammogram, she should ask for it. She might also want to think about seeing another physician."