title: Biological aggressiveness of prostate cancer in the Finnish screening trial.
abstract: Prostate cancer aggressiveness was evaluated based on pathologic characterization of cases detected in the Finnish prostate cancer screening trial. The trial population consists of 80,458 men aged 55-67 years. A total of 32,000 men were randomized to the screening arm. The remaining 48,000 men formed the control arm. The interval cases and cancers among nonparticipants and in the control arm were identified from the Finnish Cancer Registry. Random samples were selected from screen-detected cases (126 of 543 in the first and 133 of 508 in the second round) and control arm cancers (133 out of 863), in addition to all 92 interval cancers and 106 cases among nonparticipants. All the biopsies were regraded according to the Gleason system. The expression of the proliferation antigen Ki-67 was determined in 479 cases (72%). More than half of the tumors diagnosed in the first round of screening were high-grade cancers (Gleason 7 or higher). In the second round, the proportion of low-grade cancers increased from 47% to 70%. Cancers in the screening arm were more commonly focal and fewer bilateral cancers were detected. The cancers among nonparticipants were the most aggressive group. The aggressiveness of the interval cancers was between the cancers detected in the first and the second round. Our results indicate that prostate cancers detected through screening are less biologically aggressive. This was most notable after the first screening round. Nonparticipants had more aggressive cancers.
authors.affiliation: Department of Pathology, Tampere University Hospital, Tampere, Finland. marita.laurila@pshp.fi
authors.forename: Marita
authors.initials: M
authors.lastname: Laurila
authors.forename: Teuvo L J
authors.initials: TL
authors.lastname: Tammela
authors.forename: Anssi
authors.initials: A
authors.lastname: Auvinen
authors.forename: Jorma
authors.initials: J
authors.lastname: Isola
authors.forename: Tapio
authors.initials: T
authors.lastname: Visakorpi
authors.forename: Tiina
authors.initials: T
authors.lastname: Luukkaala
authors.forename: Liisa
authors.initials: L
authors.lastname: Määttänen
authors.forename: Mirja
authors.initials: M
authors.lastname: Ruutu
authors.forename: Martti
authors.initials: M
authors.lastname: Ala-Opas
authors.forename: Markus
authors.initials: M
authors.lastname: Mildh
authors.forename: Paula
authors.initials: P
authors.lastname: Martikainen
mesh_terms: D000368:Aged; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D009367:Neoplasm Staging; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: D019394:Ki-67 Antigen