Although some studies suggest that conformity with consensus recommendations for breast cancer therapy is associated with increased survival, the data are not clear. We identified patients in four hospital-based breast cancer registries in Korea who had undergone primary curative surgery (stage 0-III) from 1993 through 2002 (n = 8,407). We collected demographic and clinical characteristics such as age, stage, treatment, and hormone receptor status. We gathered 1993-2004 mortality data by linkage to the National Statistical Office. During the follow-up period of 43,145 person-years (mean, 5.13 years), we identified 899 deceased cases. We used the standard Poisson regression model to estimate the hazard ratio (HR) for survival in relation to conformity with guidelines for chemo-, hormone, and locoregional therapy. Guideline compliance for systemic therapy increased from 24.0% in 1993 to 83.8% in 2002. Among mastectomy patients with <4 positive lymph nodes and tumors <5 cm, post-mastectomy radiotherapy was associated with poor survival (HR 2.07; 95% CI: 1.53-2.81). Tamoxifen use was associated with better survival among patients with hormone receptor-positive tumors (HR 0.57; 95% CI: 0.45-0.73) and with poorer survival among hormone receptor-negative patients who had affected nodes (HR 1.58; 95% CI: 1.01-2.44). Relative to conformity, non-conformity with both chemo- and hormone therapy guidelines was associated with a 76% higher risk of death. Compliance with consensus recommendations for chemo- and hormone therapy is significantly associated with better survival. Overuse of post-mastectomy radiotherapy and tamoxifen beyond the consensus recommendations may be harmful.
Bibliographical noteFunding Information:
from the U.S. National Institutes of Health (NIH) and the International Breast Cancer Study Group [1, 2]. Several studies have shown reasonable compliance with the consensus recommendations for treatment of breast cancer [3, 4], and while compliance is associated with a significant improvement in survival , the clinical impact of the guidelines remains unclear.
Acknowledgment This work was partially supported by National Cancer Center Grant 04101502 and National Cancer Center Grant 0510040.
All Science Journal Classification (ASJC) codes
- Cancer Research