Natural evolution of prostate cancer

The course of untreated or only palliatively treated prostate cancer was studied in two large unselected populations. The first population comprised 514 patients (mean age 74 years at diagnosis) who were all followed to death and represented patients in different stages and grades at diagnosis. The second population included 490 men (mean age 68 years at diagnosis) with newly detected prostate cancer diagnosed during 1960 to 1980 and who survived for at least 10 years after diagnosis. Of the patients with stage M0 at diagnosis 50% ultimately died of prostate cancer. In early stage prostate cancer most deaths during the first 10 years were due to unrelated causes while prostate cancer was the dominant cause of death after 10 years. All the different stages and grades had an almost straight-falling cause-specific survival curve and all curves ended close to zero after 25 years. This means that prostate cancer deaths continue to occur as long as there are patients at risk and in none of the groups examined did the risk decline after a certain time. When a comparison was made with other studies on deferred treatment (corresponding subgroups were extracted) very similar results were found. However, the overall impression of the results looked very different when follow-up was extended from 10 to 25 years. Apart from a high mortality, a high morbidity was also found in patients who died from prostate cancer; this was significantly higher than in those who died of unrelated diseases. Patients at stage M0 at diagnosis who ultimately died had more frequent problems with local tumour growth than those who were at stage M1 at diagnosis. Early prostate cancer is usually a very slow-growing disease but it has a malignant potential and if the host lives long enough he will be at high risk for prostate cancer death irrespective of stage or grade at diagnosis.