Non-linear transformations of age at diagnosis, tumor size, and number of positive lymph nodes in prediction of clinical outcome in breast cancer.
Carina ForsareMartin BakAnna-Karin FalckDorthe GrabauFredrika KillanderPer MalmströmLisa RydénOlle StålMarie SundqvistPär-Ola BendahlMårten FernöPublished in: BMC cancer (2018)
Categorization of each factor into three to four groups was found to improve prognostication compared to dichotomization. The additional gain by allowing continuous non-linear effects modeled by FPs or RCS was modest. However, the continuous nature of these transformations has the advantage of making it possible to form risk groups of any size.