387P5-years conditional disease free survival and overall survival for breast cancer patients in South Korea

Background Most of breast cancer patients survive for a long-term period. The existing assessment of survivors’ prognosis has had some limitations in breast cancer because it is based on an evaluation at the time of diagnosis. Conditional survival reflects change over time after diagnosis and treatment of cancer. Conditional disease-free survival (CDFS) and conditional overall survival (COS) can provide more accurate prognosis to breast cancer patients. In this study, we aimed to determine 5-years CDFS and COS according to disease-free period after diagnosis and treatment of breast cancer in Korea. Methods We retrospectively reviewed clinical data of 5664 patients aged 16 to 86 who underwent curative surgery for breast cancer between January 2000 and December 2008 at Samsung Medical Center, a single tertiary hospital in Korea. The CDFS and COS rates were based on cumulative DFS and OS estimates up to 15 years using the Kaplan-Meier method. Results At baseline, each 5-years DFS and OS were 88.0% and 93.8%. For patients who kept disease free status from 1 to 9 years after surgery, the 5-years CDFS rates were calculated as 88.7%, 90.7%, 91.6%, 91.1%, 91.5%, 91.0%, 89.5%, 86.1% and 86.1%, respectively. The 5-year COS rates of the patients who had survived from 1 to 9 years after surgical treatment were calculated as 92.6%, 92.1%, 91.2%, 91.0%, 89.4%, 85.6%, 80.7%, 75.3%, and 73.0%, respectively. Conclusions Our study showed that 5-years CDFS and COS for most patients who have breast cancer in Korea seemed to be good prognosis for a long time. However, cancer recurrence tended to occur after a long period postoperatively. Further study is required to identify risk factors associated with recurrence after several years in Korean breast cancer patients. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.