An elevated rate of increase in prostate specific antigen (PSA) levels is the most significant predictor of aggressive form of prostate cancer, according to a new study published in the journal Cancer.
The study suggests if the rate of PSA increase prior to treatment (PSA Velocity) is more than 2 ng/ml/year, it is an indication of a high risk of death from prostate cancer.
According to the researchers, the new findings attain significance with recent studies suggesting that factors like microscopic features of the tumour (Gleason score), and size, spread and location of the disease are not very effective to determine prognosis.
Dr. Anthony D'Amico of Boston's Brigham and Women's Hospital and colleagues characterised PSA velocity significant in prostate cancer-specific mortality (PCSM) rates following treatment with radical prostatectomy (RP) or radiation therapy (RT).
The researchers reviewed data from 948 men with localized prostate cancer who had one or more high-risk factors, and found that PSA velocity appeared to be the most important single prognostic factor. They observed that men who had multiple risk factors died from their disease significantly earlier than those who had only one factor.
Among men who underwent treatment with RP or RT, 44 per cent and 28 per cent, respectively, had pre-treatment PSA velocities of 2 ng/ml/year as their only identified high-risk factor.
It was observed that of those men who died with only one identified high-risk factor, 88 per cent of RP-treated patients and 80 per cent of RT-treated patients had pre-treatment PSA velocities of 2 ng/ml/year.
The study authors have also pointed out at the results of various other studies that have shown that the time to death shortens as PSA velocity increases, which suggests that further research should examine using stratified PSA velocities to assess risk in men with localised disease.
"These findings highlight the ability of a pre-treatment PSA velocity 2 ng/ml/year alone to identify men with aggressive prostate cancer and in whom effective systemic treatment in addition to mono-therapy with RP or RT is needed to decrease PCSM rates," conclude the authors.