Five year survival analysis of patients with clinical stages I and IIA breast cancer who received initial treatment at North Carolina hospitals

North Carolina Public Health CaflS Studies A Special Report Series by the Center for Health Informatics and Statistics 1908 Mail Service Center, Raleigh, N.C. 27699-1908 www.schs.state.nc.us/SCHS/ No. 123 December 2000 Five Year Survival Analysis of Patients with Clinical Stages I and IIA Breast Cancer who Received Initial Treatment at North Carolina Hospitals by Fatma Simsek, MPH ABSTRACT This study examines the impact of the three major breast cancer treatment types, age, and stage at diagnosis on the survival rates of breast cancer patients. Research indicates that the survival rates for patients treated with Breast Conserving Surgery (BCS) and radiation (when given together, these two treatments are known as Breast Conservation Treatment or BCT) are comparable to those undergoing mastectomy. In North Carolina, this finding has not been examined on a population level. North Caro¬ lina Cancer Registry data for all 3,059 stage I and IIA (earliest invasive) breast cancer cases treated at North Carolina hospitals in 1995 were used in this study. Of the 3,059 patients, 1,721 (59%) under¬ went mastectomy. The total numbers of patients who underwent BCT and BCS were 750 and 431, respectively. Five-year survival was evaluated using the Cox proportional hazards method. Although multivariate analyses demonstrated that the 5-year overall survival rates of patients treated with BCT was not significantly different from those who underwent mastectomy, the survival rate of BCT pa¬ tients was significantly higher than that for BCS patients (P-value = 0.046). Survival differences be¬ tween stages I and IIA were statistically significant (P-value = 0.0001). No significant survival difference was found according to age group. These data indicate that in a large population of breast cancer patients, survival rates are comparable among three standard treatments. There is also some evidence to indicate that Breast Conservation Treatment for stages I and IIA breast cancer patients is a safe alternative to mastectomy and preferable to BCS alone. NORTH CAROLINA DEPARTMENT OF HEALTH AND HUMAN SERVICES