Prolonged time to breast cancer surgery and the risk for metastasis

Background A growing breast cancer (BC) is associated with an inherent risk of metastasis (MET). If surgical treatment of a BC is delayed, the prognosis worsens continuously with increasing tumor diameter (TD). This frequently overlooked topic in healthcare is currently the subject of debate. Methods Population-based data on BC incidence and surgery waiting period for the U.S. and Germany are used to examine the resulting risks. BC growth and initiation of MET are calculated in a simulation approach using hormone receptor status (HR), tumor volume doubling time (VDT), and TD- dependent survival. Results The U.S. and Germany report 287,850/71,375 BCs annually. Based on an initial mean TD of 19.8mm 15-year mortality in both countries is estimated using a Gompertz function at 19.6% without surgical delay. VDT of HR+ and HR- BCs differs by a factor of 2.4, leading to an estimated mortality increase of 1.34/3.26% (HR+/HR-) if all surgical procedures are pushed back by five weeks. The mean delay in the U.S. and Germany is 33.7/26.0 days respectively. Prolonged waiting periods lead to estimated 4,676/918 additional BC deaths or a 1.6/1.2% rise in BC mortality rate. Further increases are due to MET relapse up to 25 years after diagnosis. Conclusions A growing tumor can continuously initiate MET with every millimeter. The results of this study offer replicable and valid evidence, based on publicly available clinical and population-based data, that confirmed BCs should be treated according to HR status as soon as possible.