Clinical correlates to PSA spikes and positive repeat biopsies after prostate brachytherapy

Abstract

Objectives To make some preliminary observations regarding the biochemical characteristics of the doubly confusing picture of prostate-specific antigen (PSA) spikes and histologically positive biopsies after prostate brachytherapy. Methods All patients reported here had a pretreatment PSA level of less than 10 ng/mL and Gleason score of 4 to 6. Transperineal iodine-125 implants (without supplemental beam radiotherapy) were performed as previously described. After implantation, patients were followed up routinely, with repeat PSA measurements and physical examinations every 4 to 6 months. The timing of the postimplant PSA measurements was at the discretion of the patients and their doctors. No patient received preimplant or postimplant hormonal therapy. Repeat biopsies were performed from 13 to 31 months (median 22) after implant. Results Patients' prespike nadir ranged from 0.9 to 1.7 ng/mL (median 1.2). The time from the implant to the start of the spike ranged from 9 to 24 months (median 13). The time from implant to the spike peak ranged from 12 to 30 months (median 22). The peak spike height ranged from 2.6 to 8.4 ng/mL (median 3.1). Patients' last PSA value ranged from 0.1 to 0.5 ng/mL (median 0.2). Conclusions Transient PSA rises can occur even in the presence of a persistently positive biopsy, and patients and physicians should not feel compelled to rush ahead with salvage therapy. On the basis of the patient data reported here, it appears that a spike up to 10 ng/mL is still consistent with cancer eradication.