TURP cavity poster for ABS

1
Correlation between erectile dysfunction and dose
to the penile bulb and neurovascular bundles
following prostate brachytherapy Amy N. Solan1,
Richard G. Stock1, Jamie A. Cesaretti1, Nelson N.
Stone21Department of Radiation Oncology, Mount
Sinai School of Medicine, New York,
NY 2Department of Urology, Mount Sinai School of
Medicine, New York, NY
Purpose/Objective To evaluate the relationship
between erectile function and dose to the penile
bulb (PB) and neurovascular
bundles (NVBs) after real-time
ultrasound-guided prostate brachytherapy.
Presentation 2267
Materials/Methods

• One hundred forty-seven patients who underwent
  prostate brachytherapy between January 2003 and
  February 2006 met the following eligibility
  criteria
• (1)   Treatment with 125I brachytherapy to a
  prescribed dose of 160 Gy /- hormones
  without supplemental external beam
  radiation therapy
• (2)   Identification as potent prior to the
  time of implantation based on a score ?2
  on the physician-assigned Mount Sinai
  Erectile Function Score (MSEFS) and a
  score ?16 on the abbreviated International
  Index of Erectile Function patient
  assessment
• (3)   Minimum follow-up of 12 months.
• PB and NVBs were contoured on 1-month postimplant
  CT imaging as in Figures 1 and 2, respectively.
• Volume of PB receiving 100 of prescription dose
  (PB V100) and dose to hottest 5 of PB (PB D5)
  were recorded.
• For each NVB structure, volumes receiving 100
  and 150 of prescription dose (NVB V100 and V150)
  were recorded.
• Median follow-up was 25.7 months.
• Postimplant impotence was defined as MSEFS lt2.

Figure 1. PB (cyan) is identified on axial CT
posterior to the corpora cavernosa, anterior to
the levator ani, and between the paired lateral
crura.
Figure 2. Because the NVBs are difficult to
define on CT imaging, we focused on dose to the
fascial plane volumes that house the NVBs. Right
(green) and left (yellow) NVBs and surrounding
fascial planes were outlined as triangular
structures bounded by the posterolateral edge of
the prostate (red), the levator ani muscle, and
the rectal wall (blue).
Results
Conclusions

• PB doses are low following real-time
  ultrasound-guided prostate brachytherapy.
• There was no relationship between dose to the PB
  and the development of impotency.
• Dose to the NVBs also showed no correlation to
  postimplant impotence.
• Such a dose response may exist, but our implants
  were too consistent with respect to technique and
  delivered dose over the selected time period to
  detect such a relationship.