NATURAL EVOLUTION OF PROSTATE-CANCER

The course of untreated or only palliatively treated prostate cancer w as studied in two large unselected populations. The first population c omprised 514 patients (mean age 74 years at diagnosis) who were all fo llowed to death and represented patients in different stages and grade s at diagnosis. The second population included 490 men (mean age 68 ye ars 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 pros tate cancer. In early stage prostate cancer most deaths during the fir st 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 an d all curves ended close to zero after 25 years. This means that prost ate cancer deaths continue to occur as long as there are patients at r isk and in none of the groups examined did the risk decline after a ce rtain time. When a comparison was made with other studies on deferred treatment (corresponding subgroups were extracted) very similar result s were found. However, the overall impression of the results looked ve ry different when follow-up was extended from 10 to 25 years. Apart fr om a high mortality, a high morbidity was also found in patients who d ied 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 th an those who were at stage M1 at diagnosis. Early prostate cancer is u sually a very slow-growing disease but it has a malignant potential an d if the host lives long enough he will be at high risk for prostate c ancer death irrespective of stage or grade at diagnosis.