Systems and methods, for use during treatment of an individual having a certain disease and undergoing treatment under a specific line of treatment, are presented. The system comprises: a data input utility for receiving input data of the individual, the input data comprising two or more measured values of at least one medical parameter being measured at two or more respective time points, and comprising at least one in-treatment measured value measured since onset of the treatment under the specific line of treatment； a data processing utility for utilizing the input data and processing a disease progression model, corresponding to the certain disease, and determining from the measured values one or more disease stage indicator values, and processing the one or more disease stage indicator values to generate output data indicative of disease progression occurring within a predetermined treatment period； and a data output utility for outputting the output data thereby enabling a user of the system to decide about the course of treatment.
