Prognosis of incidental prostatic cancer in Aust-Agder County, Norway

The clinical significance of dividing incidental prostatic cancer into T0 focal (A1) and T0 diffuse (A2) is well documented, but criteria for the distinction vary considerably. Eighty-four patients with incidental prostatic cancer over a 5-year period comprise all newly diagnosed cases from an area of 94,000 inhabitants in the Aust-Agder County in Norway. This represents 13% of the patients operated upon for apparently benign prostatic hyperplasia. Of these patients, 80 with a mean age of 73.9 years did not receive any additional treatment after prostatectomy until progression (deferred treatment) and were followed up for 2-7 years. Three chips or less of well-differentiated cancer were defined as T0 focal (n = 18), all other cases were T0 diffuse (n = 62). Sixty-nine patients (86%) were free of progression. Eighteen patients died of causes unrelated to prostatic cancer. Progression occurred in 11 patients (14%) at a mean time interval of 39 months after diagnosis, and 3 patients died of prostatic cancer. Related to grade, progression occurred in 2% of the G1 tumors, in 25% of G2, and in 40% of the G3 tumors. When a tumor volume of 25% was chosen as level of distinction between T0 focal and T0 diffuse, 25 patients (31%) changed the stage to T0 focal without any impact on prognosis.