There is substantial evidence to indicate that asymptomatic prostate cancer (APC) was very common in the 1980s and the decades that preceded them. Unfortunately, it is not recorded as a distinct disease entity in cancer registries, making precise epidemiological characterisation difficult. However, autopsy series show a high incidence of occult prostate cancer in elderly men dying of other causes. Many patients diagnosed with localised prostate cancer were treated by prostatectomy or by radiotherapy; when these patients were followed in large case series, there was a substantial rate of relapse after long intervals during which they were free of symptoms due to disease, although they were not always free of symptoms due to treatment. Then there were asymptomatic men whose prostate cancer was followed initially without treatment, as well as those with metastatic disease that was either silent or became so after treatment with orchidectomy or other androgen ablation therapy. Certainly, APC was common. And now, in the new Millennium, what is the incidence of APC? Perhaps we have not progressed quite as far as with smallpox, but we are getting close. APC is now a very rare disease. So, when that august group of (mostly) men convene in Stockholm to award the next Nobel prize in medicine, where will they find the key discovery that led to this remarkable reduction in incidence of APC. They might start by exploring Medline, using the keywords “prostate” and “PSA” (prostate-specific antigen): this will provide them with a list of more than 5000 articles, all published since 1982. The first studies of the relationship between serum levels of PSA and the presence of prostate cancer appeared in 1986, and by the following year a large study published in the New England Journal of Medicine had set in motion the avalanche that assured the end of peaceful coexistence between microscopic deposits of prostate cancer cells and their asymptomatic hosts. An inexpensive blood test had been discovered, which could provide patients and their doctors with reliable evidence that prostate cancer cells were present. No longer do our patients arrive for their annual checkup, enjoying their lives in blissful ignorance of their APC. Now they arrive monthly, flustered and anxious, some of them with graphs or computer print-outs in hand. They no longer have APC, but rather SPC – symptomatic prostate cancer. Prostate cancer in its active form has always been associated with some nasty symptoms: local effects due to urinary obstruction or bowel problems, and pain and fatigue when the cancer is metastatic (Figure 1). Now we have added another symptom, possibly the most common of all, to ensure that virtually every patient who harbours a prostatic cancer cell shall suffer from, rather than live with, this disease. That symptom is a disabling anxiety as a result of their knowledge of their serum PSA, a state that Klotz has referred to as PSAdynia. Is it for this that we have cured APC? And what have we gained? Experts in urologic oncology have almost come to blows when discussing the merits of using serum PSA to screen for prostate cancer, which surely indicates that supporting evidence for benefit is rather controversial, and that if there is gain, it is not very great. A serum marker is useful if it can be used to detect disease earlier than by symptoms or signs, and thereby increase the probability of cure or the duration of survival. Certainly, screening by serum PSA can detect prostate cancer in asymptomatic men. Since widespread introduction of PSA screening in the United States, the incidence of prostate cancer in white men has doubled from about 55/100 000 in Figure 1. Scintigram of patient with metastatic prostrate cancer.