The quality of a woman's social networks -- the personal relationships that surround an individual -- appears to be just as important as the size of her networks in predicting breast cancer survival, Kaiser Permanente scientists report in the current issue of Breast Cancer Research and Treatment.

Previous research has shown that women with larger social networks -- including spouses or partners, female relatives, friends, religious and social ties, and ties to the community through volunteering -- have better breast cancer survival. This study is among the first to show that the quality of those relationships also is important to survival.

The study included 2,264 women who were diagnosed with early-stage, invasive breast cancer between 1997 and 2000, and who were part of the Life After Cancer Epidemiology (LACE) study. After providing information on their personal relationships, they were characterized as socially isolated (few ties), moderately integrated, or socially integrated (many ties).

"We found that women with small social networks had a significantly higher risk of mortality than those with large networks," said Candyce H. Kroenke, ScD, MPH, a research scientist with the Kaiser Permanente Northern California Division of Research and lead author of the study.

The study found that socially isolated women were 34 percent more likely to die from breast cancer or other causes than socially integrated women. Specifically, larger social networks were "unrelated to recurrence or breast cancer mortality, (they) were associated with lower mortality from all causes," the authors wrote.

Researchers measured levels of social support from friends and family using a survey that asked women to rate the quality of their relationships on a five-point scale within the past week. For example, the questions included, "My family has accepted my illness," "family communication about my illness is poor," and "I feel distant from my friends." Based on their survey results, the women were additionally characterized as having high or low levels of social support.

The study found that levels of support within relationships were important risk factors for breast cancer mortality. "Women with small networks and high levels of support were not at greater risk than those with large networks, but those with small networks and low levels of support were," Kroenke said. In fact, women with small networks and low levels of support were 61 percent more likely to die from breast cancer and other causes than those with small networks and high levels of support.

"We also found that when family relationships were less supportive, community and religious ties were critical to survival. This suggests that both the quality of relationships, rather than just the size of the network, matters to survival, and that community relationships matter when relationships with friends and family are less supportive."

The women were recruited primarily from the Kaiser Permanente Northern California Cancer Registry (83 percent) and the Utah Cancer Registry (12 percent), and enrolled in the study between 11 and 39 months post-diagnosis. After an average of 11 years post-diagnosis, 410 women had died from all causes and 215 from breast cancer.

The study suggests that interventions designed to help women with breast cancer improve the quality of their relationships could have an impact on breast cancer outcomes, Kroenke noted. "Women in the LACE study also gained health advantages from developing community and religious ties."

This study was funded by National Cancer Institute Grant No. R01CA129059, Molecular Profiles and Lifestyle Factors in Breast Cancer Prognosis (LACE3).

Co-authors of the study were Charles Quesenberry, PhD, Marilyn L. Kwan, PhD, Adrienne Castilllo, MS, RD, and Bette J. Caan, DrPH, of the Kaiser Permanente Division of Research; and Carol Sweeney, PhD, of the University of Utah Division of Epidemiology.