Natural history of low-stage prostatic cancer and the impact of early detection.

An expanding and increasingly older population, a rising incidence of prostate cancer, and uncertainties regarding treatment effectiveness have made this disease a target of special concern. The natural history of the cancer must be a consequence of host-tumor interactions, but little is known for sure about this subject. The growth rate of the tumor is determined by many factors, including genetic instability. At present, tumor grade, volume, and ploidy are the most useful techniques for judging the growth rate and metastatic potential. Stage A1 tumors generally are indolent, whereas stage A2 tumors are more aggressive. The natural history of stage B lesions is not well documented. The author asks two questions (Is cure necessary in those in whom it may be possible? Is cure possible in those in whom it may be necessary?) and reviews the problems inherent in screening for prostate cancer at this time.