[Digital image analysis in pathology--exemplified in prostatic cancer]

Digital image analysis is increasingly used in medicine. This paper reviews image analysis methods currently used in pathology. To exemplify established and future use of these methods, we present our own research and available literature on prostate cancer. DNA ploidy examinations mean measuring nuclear DNA content. A review of available literature shows that DNA ploidy is a very good prognostic marker in early and localized prostate cancer. Nevertheless, request for such examinations is sparse, in contrast to what is the case for gynecological cancers. In addition to assessing nuclear DNA content, we have today the means of quantitatively assessing the chromatin organisation. Such nucleotyping and texture analysis of chromatin has been shown to give significant diagnostic and prognostic information both in localized and advanced prostate cancer. DNA ploidy and nucleotyping are methods that analyze features of single cells. New methods for describing tissue architecture in an objective and reproducible way have been developed in our department. Preliminary results demonstrate the ability of these methods to discriminate between groups of prostate cancer patients with good or poor diagnosis. Digital techniques in combination with new methods from molecular biology have a potential for reducing workload, with parallel assessment of a large number of markers on large populations. The combination of traditional, molecular and digital pathology already offers the possibility of improved diagnostic and prognostic activity. However, there is the challenge of actually employing these methods. DNA ploidy for localized prostate cancer is only one example of a reliable prognostic marker that is not used to its full potential.