NCIt definition : A process that manifests as the worsening of a disease over time.;
Alternative definition : NCI-GLOSS: In medicine, the course of a disease, such as cancer, as it becomes worse
or spreads in the body.; CDISC: A disease, condition, or injury that is increasing in extent or severity.;
NCIt note : This concept is most often used for chronic and incurable diseases where the stage
of the disease is an important determinant of therapy and prognosis.;