CHICAGONerve-sparing prostatectomy has become increasingly common as
younger men diagnosed with prostate cancer seek to preserve erectile function.
Although postoperative radiotherapy has improved control of prostate cancer,
few studies have examined its effect on erectile function.
Researchers from Baylor College of Medicine, Houston, evaluated
intensity-modulated radiation therapy (IMRT) after nerve-sparing prostatectomy.
Even with high radiation doses (nearly 70 Gy) delivered to the prostatic bed
and surrounding nerves, the technique did not negatively affect potency,
reported Michael Bastasch, MD, radiation oncology resident in the Department of
Radiology, at the 87th Annual Meeting of the Radiological Society of North
America (RSNA abstracts 37 and 38).
The first study evaluated erectile function, defined as an erection
sufficient for vaginal penetration, in 51 men between the ages of 46 and 77 who
had aggressive prostate cancer. Eighty percent of the men in the study had
tumors with Gleason scores between 7 and 10, and all had stage T2 or T3
lesions. Approximately half of the men underwent bilateral and half unilateral
The men then received IMRT at a mean dose of 69.6 Gy (range, 64 to 72.3 Gy).
Their erectile function was assessed by questionnaire before and after
radiotherapy, and the men were followed for a median of 27.2 months (range,
15.9 to 38.7 months). Of the 51 men who underwent nerve-sparing prostatectomy,
18 remained potent afterward, and all 18 remained potent after IMRT, regardless
of the radiation dose.
"Dosimetric parameters broken down on the basis of potency status
reflected the fact that we did not take potency status into account at the time
of treatment planning and prescription," Dr. Bastasch said. The group’s
initial conclusion, therefore, was that the dose of radiotherapy did not have
an adverse effect on the patient’s potency status postoperatively. The
results need to be confirmed by longer follow-up and studies involving larger
cohorts, Dr. Bastasch noted.
Searching for Causes
The second study further explored why some men became impotent after
nerve-sparing prostatectomy and some did not by analyzing factors associated
with the patient (age, medical and psychiatric comorbidities, medication
history, body mass index, vital signs, and previous surgical history); the type
of surgical procedure; the use of hormonal ablation; and the nature of the