Medicare beneficiaries who had more primary care physician (PCP) visits preceding a diagnosis of breast cancer had better outcomes, including greater use of mammography, reduced odds of late-stage diagnosis and lower breast cancer and overall mortality, according to a study published in the September/October issue of Annals of Family Medicine.

As the proportion of U.S. physicians entering the primary care field wanes, experts have voiced concerns about the implications for cancer outcomes.

However, the effects of primary care on patient outcomes have not been determined. “Understanding the relationship between primary medical care and cancer outcomes is important in preparing for the major changes that are occurring to our nation's healthcare system,” wrote Richard G. Roetzheim MD, MSPH, of the department of family health at the University of South Florida in Tampa, and colleagues.

Roetzheim and colleagues mined the Surveillance Epidemiology and End Results (SEER)-Medicare database to examine the relationship between primary care and breast cancer outcomes. The researchers identified 105,105 Medicare beneficiaries (mean age 76.5 years) diagnosed with breast cancer between 1994 and 2005.

They tabulated primary care and non-primary care office visits in the 24-month period preceding diagnosis (excluding the three-month period prior to diagnosis) and classified stage at diagnosis, likelihood of mammogram in the two-year period prior to diagnosis and all-cause and breast cancer mortality.

The researchers reported 55 percent of women had a mammogram in the three- to 27-month period prior to diagnosis, and 83.7 percent of these were ordered by a primary care physician. Women who had more PCP visits had higher odds of undergoing mammography; those who had 10 or more visits had four times greater odds of prior mammography compared with women having zero or one visit. Prior mammography was linked with lower odds of stage 3 or 4 disease.

“The odds of late-stage disease decreased with increasing number of ambulatory primary care and non-primary care physician visits,” wrote Roetzheim and colleagues. Women with 10 or more visits were 50 percent less likely to have late-stage disease compared with those having zero to one visit.

Mortality also improved with increasing numbers of primary care visits. “Women having more than 10 primary care visits had 41 percent lower breast cancer mortality compared with women having zero to one visit when adjusting for confounders other than stage and size.”  

Greater use of mammography and earlier stage diagnosis partially explains improved outcomes among women with more visits, according to the authors. They cited several other areas in which the involvement of a PCP may help improve outcomes: assisting with treatment decisions, facilitating access to treatments, ensuring access to treatments and surveillance and facilitating access to psychosocial care.

Given the link between primary care and improved breast cancer outcomes, Roetzheim and colleagues concluded: These findings suggest adequate primary medical care may be an important factor in achieving optimal outcomes for patients with a diagnosis of breast cancer.