Biochemical relapse of prostate cancer. Evidence after radical surgery.
BACKGROUND: The aim of this study was to investigate, whether ultrasensitive PSA assays can help to find a lower cut-off value for biochemical recurrence of prostate cancer after resection. MATERIALS AND METHODS: This was a retrospective analysis of the patient files of 113 men with prostate cancer who underwent surgery. The mean follow-up time was 26 months. PSA measurements were performed with the ultra sensitive Immulite assay (DPC, USA), with an analytical sensitivity of 0.001 ng PSA/ml. Patients with baseline PSA levels > 0.1 ng/ml after surgery were excluded. Different cut-off levels for PSA were applied on the values and PSA doubling-times calculated. RESULTS: Maximum PSA 0.01 ng/ml, 0.05 ng/ml, 0.1 ng/ml, 0.2 ng/ml and > 0.4 ng/ml were reached by 87%, 61%, 50%, 42% and 20% of patients, respectively. From a cut-off point of 0.1 ng/ml the chance of further progression to PSA levels of 0.2 ng/ml and 0.4 ng/ml was 75% and 40%, respectively. The PSA doubling time was 2.1 months in patients with PSA values > 0.4, 15 months for patients below 0.4 ng/ml and 22.4 months for patients whose PSA never exceeded 0.1 ng/ml. CONCLUSION: PSA cut-off values below 0.4 ng/ml lack sufficient clinical significance. However, patients with PSA values > 0.1 ng/ml should be monitored thoroughly and at shorter intervals, as further increase, i.e. tumour progression, is very likely to occur.