The fall in incidence of prostate carcinoma

Stephenson et al., using data from the Utah Cancer Registry, reported a dramatic drop in the incidence rate for prostate carcinoma between 1992 and 1994. Is this an oddity in Utah, or could this finding be replicated elsewhere? The 1980s saw a rapid rise in the reported incidence of prostate carcinoma. This occurred in concert with the introduction and increased use of the prostate specific antigen (PSA) test. The Surveillance, Epidemiology, and End Results (SEER) program reported an increase in the incidence rate from 84.4 to 163 per 100,000 men between 1984 and 1991. This rise resulted in considerable concern among men, physicians, governmental entities, insurers, and policy makers. Because the Utah findings were also seen in data from The Upper Midwest Oncology Registry Services (TUMORS), a 28-member consortium of hospitals, we reviewed data from the Minnesota Cancer Surveillance System (MCSS), which is population- and pathology-based. The results from the MCSS data base are presented along with similar data from Stephenson et al. and the appropriate SEER data in Table 1. A decrease in the incidence rate for prostate carcinoma, similar to that of the Utah Cancer Registry, was found in the MCSS data base. While the PSA tests are frequently used in Minnesota, it is not known what proportion are used for screening as opposed to diagnostic purposes. Neither Medicare nor the health plans in Minnesota cover PSA tests for screening purposes. A different speculation as to the cause of the original "increased" incidence of prostate carcinoma is that PSA now has a critical role in the diagnostic process. A PSA test is usually ordered for patients older than 50 years who present with symptoms of prostate carcinoma or have an abnormal digital rectal exam. If the PSA is elevated, patients then undergo ultrasonography, and, when recommended, a biopsy. This process often identifies a cancer much earlier than would have been possible if PSA testing had not been performed. We hypothesize that these data mean the rate of prostate carcinoma will fall back to the incidence rates seen in the mid 1980s, with more patients diagnosed in earlier stages. As PSA screening trials are undertaken, the proven value of PSA testing for the diagnosis and treatment of prostate disorders needs to be carefully considered. Charles L. Murray M.D. F.A.C.P., Gail Jolitz C.T.R., Sally Bushhouse D.V.M. Ph.D., Raymond E. Sandborgh M.A. C.P. L.P.