Description of a computer program to assess cancer antigen 15.3, carcinoembryonic antigen, and tissue polypeptide antigen information during monitoring of metastatic breast cancer. Clin Chem 2000;46:1106–13

It is time-consuming to process and compare the clinical and marker information registered during monitoring of breast cancer patients. To facilitate the assessment, we developed a computer program for interpreting consecutive measurements. The intraindividual biolog-ical variation, the analytical precision profile, the cutoff limit, and the detection limit for each marker are entered and stored in the program. The assessment procedure for marker signals considers the analytical and biologi-cal variation of the applied markers. The software pack-age contains a database that can store the interpretation of the measurements as evaluation codes together with patient demographics, information about treatment type, dates for treatment periods, control periods, and evaluation codes for clinical activity of disease. The consecutive concentrations for a patient are imported temporarily into the program from outside sources and presented graphically. Marker concentrations to be com-pared are selected with the computer mouse and the significance of the difference is calculated by the pro-gram. The program has an option for calculating the lead time of marker signals vs clinical information. The program facilitates the monitoring of individual breast cancer patients with tumor marker measurements. It may also be implemented in trials investigating the utility of potential new markers in breast cancer as well as in other malignancies. © 2000 American Association for Clinical Chemistry Many compounds have been studied in the search for tumor markers that rapidly and reliably reflect treatment response of the individual breast cancer patient or give an early prediction of recurrence or new metastases (1–3). Longitudinal monitoring studies necessitate a standard-ized set of criteria for marker assessment (4, 5). However, calculation of the significance of a change in concentra-tions is very time-consuming if performed manually (6, 7). To facilitate this process, we have developed a computer program based on our model systems for tumor marker monitoring where the significance of a change is related to the normal inherent intraindividual biologica