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October 19, 2004

Absence of screening mammograms accounts for most late- stage cancer, study finds

Reaching out to unscreened women should be a top priority, authors conclude

Seattle—What puts women in integrated health plans at greatest risk for late-stage breast cancer? Not having screening mammograms even though they have access to this test, according to a new study in the October 20 issue of the Journal of the National Cancer Institute. The study also found that older, unmarried, less educated, and lower income women are less likely to be screened.

The study was conducted by scientists at Group Health Cooperative and six other organized health plans in the Cancer Research Network—a consortium of health care organizations nationwide that studies the effectiveness of cancer-control interventions.

"This study tells us that in order to achieve the largest reduction in late-stage breast cancers, our highest priority should be reaching those unscreened women and encouraging them to have mammograms," said Stephen Taplin, MD, MPH, who led the research in his role as senior investigator with Group Health Center for Health Studies. Taplin is now a member of the National Cancer Institute’s Division of Cancer Control and Population Sciences.

"Screening is a process, not just a test," Taplin added. "Our goal was to learn where that process needs to be improved so that more women can achieve complete screening. For example, we wondered if women with positive tests were not being evaluated."

How the research was conducted

To find out where the screening process breaks down and where changes in care might have the greatest impact, the researchers examined data from 2,694 women aged 50 years and older who had breast cancer and were members of integrated health plans that provide both primary and specialty care. They compared women who had been diagnosed with late-stage breast cancer with those who had been diagnosed with early-stage breast cancer and, on the basis of their care between three years and one year prior to their diagnosis, categorized the women into one of three groups: 

1. absence of screening (when no mammogram existed)
2. absence of detection (when the earliest screening mammogram was negative), or 
3. potential breakdown in follow-up (when a screening mammogram was positive, but the diagnosis occurred more than a year later).

What the study found

The researchers found that 52 percent of the late-stage breast cancer cases were associated with an absence of screening, 39 percent with an absence of detection, and 8 percent with a potential breakdown in follow-up. They found that the odds of having late-stage cancer were nearly doubled among women with an absence of screening. Among women diagnosed with late-stage cancer, women were more likely to be in the absence-of-screening group if they were aged 75 years or older, unmarried, or did not have a family history of breast cancer. In addition, women who had less education or lower income were more likely to have been in the absence-of-screening group.

"For women, this study emphasizes the importance of getting screened regularly and within the appropriate time frame," said Taplin. "For doctors, it tells us that we need to identify the women in our practices who are not coming in even though they’re receiving reminders, to listen to them, and to find ways to encourage them to come. And for health care systems, it means considering reminder systems to reach those women who may not be seeing their providers for care."

In addition, more research needs to be done to improve the use of current technology and to develop better tools for detecting cancer, Taplin said.

About the Cancer Research Network

The Cancer Research Network (CRN) is a consortium of 11 health care organizations that collaborate on studies of cancer epidemiology, prevention, early detection, and control in the context of health care delivery systems. Together, the participating organizations have access to health care data on 9 million people, or 3.5 percent of the U.S. population. The CRN is supported by grants from the National Cancer Institute. Group Health Center for Health Studies provides scientific and administrative leadership for the network.

"This study was only possible through collaboration with scientists from across the CRN," Taplin noted. CRN scientists who contributed to this study of late-stage breast cancer are:

• Laura Ichikawa, MS, Robin Altaras, Robert K. Beverly, MA, Deborah Casso, MPH, and Emily Oakes Westbrook, of Group Health Cooperative, Seattle, WA.
• Marianne Ulcickas Yood, PhD, of Henry Ford Health System, Detroit, MI.
• M. Michele Manos, PhD, and Wendy A. Leyden, MPH, of Kaiser Permanente Northern California, Oakland, CA.
• Ann M. Geiger, PhD, of Kaiser Permanente Southern California, Pasadena, CA.
• Sheila Weinmann, PhD, of Kaiser Permanente Northwest, Portland, OR.
• Joyce Gilbert, MPH, of Kaiser Permanente Hawaii, Honolulu, HI.
• Judy Mouchawar, MD, MPH, and Kimberly Bischoff, MS, of Kaiser Permanente Colorado, Denver, CO.
• Jane G. Zapka, ScD, of the University of Massachusetts Medical School, Worcester, MA.
• William E. Barlow, PhD, of Cancer Research and Biostatistics, Seattle, WA.

About Group Health Center for Health Studies

Group Health Center for Health Studies conducts research related to prevention, diagnosis, and treatment of major health problems. Funded primarily through government and private research grants, the Center is located in Seattle, Washington. Group Health is a consumer-governed, nonprofit health care system that coordinates care and coverage. Based in Seattle, Group Health and Group Health Options, Inc. serve nearly 540,000 members in Washington and Idaho.

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