Relationship between prostate cancer mortality and number of unfavourable risk factors in men treated with definitive brachytherapy

Authors


Gregory S. Merrick, Schiffler Cancer Center, Wheeling Hospital, 1 Medical Park, Wheeling WV 26003, USA.
e-mail: gmerrick@urologicresearchinstitute.org

Abstract

Study Type – Therapy (case series)
Level of Evidence 4

OBJECTIVE

To explore whether the number of unfavourable pretreatment risk factors predicts cause-specific mortality in men treated with prostate brachytherapy.

PATIENTS AND METHODS

Between April 1995 and March 2006, 739 patients were treated who had at least one of the following adverse risk factors: pretreatment prostate-specific antigen (PSA) level of >10 ng/mL, a Gleason score of ≥7, clinical stage ≥T2b, or a PSA velocity (PSAV) of >2 ng/mL/year. Supplemental external beam radiotherapy (EBRT) was delivered to 464 (62.8%) men and 301 (40.7%) received androgen deprivation therapy (ADT). Of men with more than two risk factors, 87% received EBRT and 62% received ADT.

RESULTS

The biochemical progression-free survival (bPFS), cause-specific survival (CSS) and overall survival for all patients were 95.0%, 97.9% and 70.0% at 12 years. Men with three or four risk factors had a prostate cancer-specific mortality (PCSM) at 12 years of 5.3%, vs 1.7% for men with one or two risk factors (P= 0.006). When ‘percentage of positive biopsy cores >50%’ replaced PSAV as a risk factor, men with two or more risk factors had a PCSM of 8.9%, vs 1.0% for men with one or two risk factors (P= 0.001). There was no difference in all-cause mortality between the groups in either analysis.

CONCLUSION

Multimodal brachytherapy results in high rates of bPFS and CSS, even for men with several unfavourable risk factors. Men with two or more unfavourable risk factors had a slightly greater risk of PCSM and no difference in all-cause mortality. The presence of three or four unfavourable intermediate-risk factors does not appear to clearly identify a group that requires further treatment intensification, although the percentage of positive cores might be more predictive than PSAV.

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