The “Rural Breast Cancer Survival Study” conducted by the California Center for Rural Policy (CCRP) at Humboldt State University and the Breast and GYN Health Project (BGHP) also found that breast cancer death rates for women in rural areas of the state were similar to those of women with breast cancer in urban areas, and lower compared to Humboldt County death rates. In addition, the research examined factors associated with higher death rates from breast cancer in Humboldt County and the rest of California from 1990 through 2010. Study findings will be shared by the researchers in a series of community forums throughout Humboldt County beginning with the first one scheduled for April 21, 5:30-7 p.m., Eureka Community Health and Wellness Center (visit www.rbcss.org).
The study analyzed 21 years of data on female breast cancer from a state database, the California Cancer Registry, to investigate two questions:
1. Of women who die from breast cancer in Humboldt County, what factors are associated with shorter survival?
2. How does the survival of women with breast cancer in Humboldt County compare to women in the rest of California? With women who live in urban areas or rural areas?
The study found four factors that were associated with poorer 5-year breast cancer survival in women in Humboldt County, as well as for women in the rest of California. Three of these factors – age, stage at diagnosis, and tumor grade – have been well-established as being related to a higher risk of dying from breast cancer.
- Age – Women who are 65 years and older have shorter survival than women under 45 years old;
- Stage at diagnosis – Women diagnosed at late stage breast cancer (a stage at which the tumor size is larger and has spread beyond the breast), compared to those diagnosed at early stage;
- Tumor grade – Women diagnosed with Grade 3 breast cancer have tumor cells that are more ‘abnormal,’ with more DNA damage (Grade 3), compared to women with Grade 1 cancer.
The fourth factor, marital status, was shown to be related to a higher risk of dying from breast cancer within 5 years, in women who were unmarried at the time of diagnosis, compared to married women.
Unmarried women included the following: single, divorced, widowed, and those in domestic partnerships. While several studies have found that married cancer patients have better survival than unmarried patients, a new study recently reported that the higher risk of death among unmarried cancer patients compared to married patients was not due to economic advantages, but may more likely be due to social support. Future research could further understanding of the impact of social and emotional support on cancer survival.
All four factors were associated with shorter 5-year survival from breast cancer regardless of location in the state, but women in Humboldt County with these characteristics (65 years or older, late stage diagnosis, Grade 3, or unmarried) had slightly poorer probability of 5 year survival from breast cancer, compared to their counterparts in the rest of the state. However, the difference in survival rates between Humboldt County and the rest of California were fairly small:
- Women diagnosed with late stage breast cancer in Humboldt County had a 62 percent probability of surviving at least 5 years, compared to 66 percent probability of 5-year survival among women in the rest of California.
- Women 65 years and older had a 70 percent probability of surviving at least 5 years, compared to 74 percent probability of 5-year survival among women in the rest of California.
- Unmarried women with breast cancer in Humboldt County had 75 percent probability of 5-year survival vs. 78 percent probability of 5-year survival among unmarried women with breast cancer in the rest of California.
Two trends that emerged from the analysis of 21 years of data indicated that:
• Proportionately more women in Humboldt County were diagnosed at early stage breast cancer (72 percent), compared to other areas in the state (70 percent). This indicates that the higher death rate in Humboldt County cannot be simply attributed to more women being diagnosed at late stage.
• Proportionately fewer women in Humboldt County were diagnosed at Grade 3 breast cancer (23 percent), compared to other areas in the state (28 to 31 percent). This indicates that the higher death rate in Humboldt County cannot be simply attributed to more women being diagnosed with higher grade cancer.
The study did not find significant differences in breast cancer survival among women in Humboldt County that were associated with geographic location and non-White race or other ethnicity, but the small population in Humboldt County may have limited the capability to establish statistical differences. The California Cancer Registry does not track treatment data on patients, so variables such as course of treatment and time between diagnosis and treatment could not be analyzed.
The state Public Health Department has reported that the health status of Humboldt County ranks poorly when analyzing population health indicators such as obesity, tobacco use, alcohol use, and diabetes. All of these are health risk factors that may increase risk of getting cancer, as well as surviving cancer. These are important to consider in investigating why Humboldt County’s breast cancer death rate is higher, and the Rural Breast Cancer Survival Study is an initial step in seeking to determine contributing factors. As stated by the National Cancer Institute, “Cancer is a complex topic” involving consideration of the myriad factors involved in “diagnosis, treatment, follow-up care, or decision making” – all of these are potential areas for future investigations of Humboldt County’s higher death rates from breast cancer.
The Rural Breast Cancer Survival Study was funded by the California Breast Cancer Research Program, and has been carried out as a collaboration between a community partner (BGHP) and an academic partner (CCRP). Co-principal investigators were Brenda Elvine-Kreis (BGHP) and Terry Uyeki (CCRP). Dr. Ellen Mahoney, surgical oncologist at St. Joseph Hospital and nationally recognized cancer expert, served as a consulting investigator. For information about upcoming forums or about the Rural Breast Cancer Survival Study, visit www.rbcss.org, or contact Brenda Elvine-Kreis at 707-825-8345 or brendae@hcbhp.org, or Terry Uyeki at 707-826-3404, or thu1@humboldt.edu.
The Breast and GYN Health Project is a grassroots cancer resource center for those facing breast or gynecologic cancer concerns. The California Center for Rural Policy fosters “Rural Research, for and by Rural Communities” to improve the health and well-being of rural people and environments.