Three-dimensional survival model of breast cancer patients

The established view point of survival in breast cancer patients is in terms of disease-free survival (DFS). This may be imprecise because a patient with early disease may have three different DFSs: First, from initial diagnosis until local recurrence; Second, from successful treatment of local recurrence until development of metastatic disease; Third, from complete remission of metastatic disease until recurrence of cancer. To include all three DFSs in a single model, we propose a three-dimensional survival surface for breast cancer patients. The survival surface is given as the function of tumor size and number of lymph nodes involved. The survival surface has the cusp geometry that is known to be the only stable structure for a system with two input parameters (tumor size and involved lymph nodes) and one output (DFS). The model casts new light on some views about breast cancer.