Login to Access Video or Poster Abstract: MP05-05
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Introduction

Men diagnosed after prostatectomy with seminal vesicle invasion often have external beam irradiation (EBRT) as adjuvant treatment. Typically, men treated with radiation do not have assessment or treatment for T3b because it is often not detected. We report our results of seminal vesicle biopsy (SVB) in men with higher risk features planning to undergo permanent seed implant (PSI) followed by EBRT.

Methods

Of 1981 men who treated by PSI and followed 5-22 years (mean 10), 615 (31%) with high risk features had 6 TRUS guided biopsies of the SV (3 from each side). Patients with +SVB underwent laparoscopic pelvic lymph node dissection and those with positive nodes, bone or CT scans were excluded from implantation. 3 months of hormone therapy (NHT) was followed by Pd-103 implant to the prostate (dose 100 Gy) and proximal SV and 2 months later 45 Gy of conformal or image guided EBRT to prostate and SV only. NHT was given a median of 9 months. Within 2 months after treatment CT-based dosimetry was done with radiation doses converted to the biologic effective dose (BED). Biochemical freedom from failure (BFFF) was computed by the Phoenix definition, freedom from metastasis (FFM) in men with BF by absence of a positive bone or CT scan and cause-specific survival (CSS) by freedom from death in men with clinical recurrence. Association of risk features to +SVB were compared by chi-square and linear regression (LR). Survival was computed by Kaplan-Meier estimates with comparisons by log rank and Cox hazard rates (HR).

Results

53/615 (9.4%) had +SVB. Higher stage, Gleason score (GS) and PSA were associated with a positive SVB (p<0.001). LR demonstrated significance for stage (p<0.001) and GS (p=0.001). BED was higher in patients receiving a SV implant (202. Vs. 179.3 Gy2, p<0.001). BFFF, FFM and CSS was worse for +SVB (all p<0.001). 48/53 (90.6%) with +SVB had NCCN3 (high risk) status. BFFF in these men without and with a +SVB was 88.5 vs. 74.9%, 75.3 vs. 62.2% and 70.3 vs 62.2% at 5, 10 and 15 years (p=0.023). FFM was 99.3 vs. 89.6%, 96.5 vs. 84.4% and 94.9 vs. 75% (p<0.001) and for CSS was 99.6 vs. 97.8%, 96.4 vs. 82.1% and 91.3 vs. 65.7% (p<0.001). CSS by BED < 180 vs ≥ 180 Gy2 was 55.6 vs. 76.9% (p=0.406). In these high-risk patients, prostate cancer death was 40/314 (12.7%) for men with -SVB and 8/21 (38.1%) for +SVB (OR 4.22, 95%CI 1.6-10.8). Cox HR demonstrated GS (p=0.001, HR 1.9), BED (p=0.05, HR 0.991) and +SVB (p<0.001, HR 0.125) as significantly associated with CSS.

Conclusions

Men who have pT3b disease have inferior BFFF, FFM and CSS. Advanced stage and high GS are highly associated with a +SVB. Higher radiation dose is associated with improved CSS in the pT3b patients. Taken together these data suggest SVB should be performed in men presenting with high GS and stage when considering combination radiation therapy. When performing PSI, implantation of the SVs will increase dose and improve long-term cause-specific survival.

Funding

none