BACKGROUND

TMPRSS2:ERG gene fusion is a common alteration in prostate cancer and is regulated by androgen receptor signaling. We investigated whether ERG expression, assessed by immunohistochemistry (IHC), predicts clinical outcomes in patients with intermediate- or high-risk localized prostate cancer treated with combined androgen blockade (CAB) and radiotherapy (RT).

MATERIAL AND METHODS

We retrospectively analyzed patients treated with CAB (GnRH agonists + antiandrogens) and normofractionated RT. ERG expression was evaluated using IHC. Overall survival (OS) was estimated with Kaplan-Meier curves. Prostate cancer-specific survival (PCSS), biochemical recurrence-free survival (bRFS), and progression-free survival (PFS) were assessed using competing risk models.

RESULTS

A total of 86 patients were included (median follow-up 173 months). ERG expression was positive in 69%. No significant differences were observed in OS (HR 1.03; p = 0.92), PCSS (HR 0.44; p = 0.22), bRFS (HR 0.51; p = 0.19), or PFS (HR 0.56; p = 0.30) between ERG-positive and ERG-negative groups.

CONCLUSIONS

ERG expression assessed by IHC was not associated with clinical outcomes in this population. These results do not support its role as a predictive biomarker in patients treated with CAB and RT. Further prospective studies are warranted to confirm these findings.