A contemporary discussion exists whether patients with low-risk prostate cancer (CaP) are being overtreated with local treatment modalities. This is due to a combination of the older population affected and the slow doubling time of CaP.
Dr. Warlick and colleagues from Johns Hopkins University compared a small cohort of men who elected observation with delayed intervention to a matched, but randomly selected group of historical controls.
Between 1995 and 2005, 320 men with low-risk CaP were enrolled in a trial of observation with delayed intervention. At entry, the study group had; mean age of 61 years, mean PSA of 5.1ng/ml, mean PSA density of 0.127ng/ml/cc, mean number of positive core of 1.3 and maximum percent core involvement of 10.8%. This compared to the control group entry data of; mean age of 61 years, mean PSA of 5.3ng/ml, mean PSA density of 0.089ng/ml/cc, mean number of positive core of 1.4 and maximum percent core involvement of 23.5%. Mean time to treatment was 28 and 3.5 months in the study and control groups respectively.
Curative surgery was undertaken in the study group for findings of adverse pathological features on annual biopsy (Gleason score >7), more than 2 cores positive for CaP, or more than 50%, any one core that is involved with tumor or a patients request for change in management. Of the 320 men, 38 underwent radical prostatectomy, of which 9 requested a change in management.
The primary outcome of this study was the proportion of men with non-curable disease defined as <75% chance remaining free of biochemical recurrence at 10 years. Nine (23%) of the 38 men in the delayed intervention cohort and 24 (16%) of the 150 men in the immediate treatment group met the criteria of noncurable CaP at the time of surgery.
After adjustment for age and PSA density at diagnosis, the risk of CaP was not associated with the type of intervention. Age, PSA and PSA density were each statistically associated with the presence of noncurable cancer when the median cut-point was applied. The percentage of biopsy cores involved with cancer, the number of positive cores, year of surgery and time between diagnosis and surgery were not associated with the risk of noncurable cancer.
These data suggest that this strategy of delayed intervention may not put men at risk of noncurable disease at the time of intervention. However, larger cohorts of patients are needed to validate this approach. Furthermore, the best criteria for intervention, whether the ones used in this study or PSA doubling-time used in other trials needs to be defined. The authors point out that at the very least; low-risk CaP is not a situation mandating a decision for urgent intervention.