Prolonged time to breast cancer surgery and the risk for metastasis

BackgroundA 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. MethodsPopulation-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. ResultsThe 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. ConclusionsA 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.