RSNA 2007 

Abstract Archives of the RSNA, 2007


RO52-06

Pretreatment International Prostate Symptom Score Correlates with Postbrachytherapy Erectile Dysfunction

Scientific Papers

Presented on November 29, 2007
Presented as part of RO52: BOOST: Prostate—Integrated Science and Practice Session (ISP)

Participants

Anthony Emilio Addesa MD, Presenter: Nothing to Disclose

PURPOSE

To determine the factors that may predict for erectile dysfunction (ED) following prostate brachytherapy based on use and reported effectiveness of phosphodiesterase-5 inhibitors (PDE-5I)

METHOD AND MATERIALS

95 patients with T1c-T2c prostate cancer who underwent low-dose rate TRUS-guided brachytherapy +/- external beam radiation therapy (EBXRT) were retrospectively analyzed. Minimum follow-up=12 months. Post-implant CT scans were performed 4-6 weeks following implant for dosimetry. In addition to D90 and V100, dose-volume metrics were collected for the penile bulb (PB) and the right and left neurovascular bundles (NVBR and NVBL). Patients were asked about the use and effectiveness of any PDE-5I both prior to initiation of any therapy (brachytherapy or EBXRT) and on follow-up. Each patient was given an erectile function (EF) score (between 0 and 5) based on the following scale:EF Score Definition5 = Normal EF; No PDE-5I use4 = EF sufficient for intercourse (IC) +/- PDE-5I3 = EF sufficient for IC only with PDE-5I, 100 % efficacy2 = EF sufficient for IC with PDE-5I, <100 % efficacy1 = EF insufficient for IC even with PDE-5I0 = No EF or spontaneous erections (e.g., penile implant)

RESULTS

The patients had a median follow-up of 27.4 months after brachytherapy. Median age was 66.5 years. There were 43 Caucasians and 52 African-Americans. Eighteen patients received adjuvant androgen ablation (AA) for a minimum of 4 months; 39 received supplemental EBXRT. Sixty-two had a history of smoking, 26 had diabetes mellitus (DM), and 71 had hypertension (HTN). The International Prostate Symptom Score (IPSS) prior to therapy ranged from 3 to 17 (median =7). The median EF score before any therapy (EFpre) was 4 and after treatment (EFpost) was 3. A significant association was found between the decrease in EF score and AA (p=0.0002) or DM (p=0.009). In a multivariate analysis, there was a significant association between EFpost (adjusting for EFpre) and smoking history (p=0.003), EBXRT (p=0.002), prostate D90 (p=0.035), prostate V100 (p=0.014), and IPSS (p=0.001); there was no correlation between EF and age, race, T-stage, initial PSA, Gleason Score, AA, DM, prostate volume, #seeds, or isotope. Also, no statistically significant association was found between EF and dose to either the PB or NVB. A multivariate logistic regression model of EF was obtained by dichotomizing EF groups into EF=1 (EF scores 3,4,5) and EF=0 (EF scores 0,1,2). We found that prostate D90 > 110% (adjusting for EBXRT, smoking, prostate V100 and IPSS) significantly increased the risk of ED (odds ratio = 8.7, confidence interval = 1.4 - 52.2); similarly, IPSS > 7 significantly increased the risk of ED (odds ratio = 6.7, confidence interval = 2.3 - 18.9). A bivariate analysis of EFpost by IPSS determined the following correlation: EFpost = 4.85 - 0.25xIPSS.

CONCLUSION

Patients with high IPSS on presentation have a significantly higher risk of reduced PDE-5I effectiveness, and hence ED following brachytherapy. Prostate D90 and V100 may be surrogate predictors of potential normal tissue injury in the periphery of the prostate gland. When one considers the close proximity of the NVBs to the prostate gland itself, it is not surprising that increases in D90 > 110% (i.e., higher doses to the periphery of the prostate) lead to significantly higher incidences of ED.

Cite This Abstract

Addesa, A, Pretreatment International Prostate Symptom Score Correlates with Postbrachytherapy Erectile Dysfunction.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/6000907.html