Focal HIFU is “sexual function sparing” in a cohort of 118 selected patients

A new paper in European Urology has suggested that men with localized prostate cancer who are treated by focal forms of high-intensity focused ultrasound (HIFU) have “a return to baseline International Index of Erectile Function — erectile and total International Index of Erectile Function scores” by 6 months after treatment which was maintained at 1 year.

Now this is clearly a potentially exciting finding, but it does need to be interpreted with some caution — for a variety of reasons — that we will get into below.

This new paper by Yap et al. is based on data from 118 patients, all with localized prostate cancer who were treated in one of three different clinical studies in the UK. So, for starters, these results are based on retrospective analysis of selected patient data from three different trials. Furthermore, the 118 men whose data have been “meta-analyzed” to create this report all had pre-treatment PSA levels of ≤ 15 ng/ml, Gleason scores of ≤ 4 + 3 = 7, and clinical stages of ≤ T3aN0M0, so they were not all low risk or even “fabvorable” intermediate risk. That raises important questions about how many of these patients may have recurrent disease within 5 years of their initial treatment (a matter not discussed in the current paper).

What Yap and his colleagues did was to pool the sexual domain-related, patient-reported outcome data from the selected patients in three prospective, registered studies that had a range of differing inclusion criteria. The sexual domain-related, patient-reported data included:

  • International Index of Erectile Function (IIEF-5) scores collected at baseline, and at 1, 3, 6, 9, and 12 months post-treatment
  • Use of phosphodiesterase-5-inhibitors (PDE5 inhibitors, like sildenafil/Viagra) at baseline, and at 1, 3, 6, 9, and 12 months post-treatment

IIEF-15 total and individual domain scores were used to assess overall sexual function; urinary function was assessed using the International Prostate Symptom Score (IPSS), IPSS quality-of-life, and UCLA-Expanded Prostate Cancer Index Composite continence questionnaires; and general health status was derived by means of the Charlson score.

Here is what Yap and his colleagues report:

  • Average (median) patient age was 63 years.
  • Median IIEF — erectile scores were
    • 23 at baseline
    • 9 at 1 months post-treatment (p < 0.01)
    • 20 at 12 months post-treatment (p < 0.30)
  • Changes in total IIEF and other IIEF domains were only significantly different from preoperative values at 1 and 3 months post-treatment
  • The proportions of men using PDE5 inhibitors were
    • 10 percent at baseline (pre-treatment)
    • 43 percent at 6 months post-treatment
    • 42 percent at 9 months post-treatment
    • 37 percent at 12 months post-treatment
  • The only baseline determinants of post-treatment erectile function were total IIEF and IIEF — erectile function scores (p = 0.002).

The major problem with this study is that the follow-up period was only 1 year. This begs two key questions:

  • Does recovery of erectile function continue to improve over the next 12 months, such that at 24 months post-treatment the median IIEF — erectile scores have returned to about 23 (the original baseline level) and
  • What is the rate of biochemical recurrence-free survival of these 118 patients at 1, 2, and 5 years post-treatment.

As Dr. Scott Eggener of the University of Chicago stated in an e-mail quoted by Medscape,

The data suggest that focal treatment preserves sexual function in most men; while encouraging, it ultimately needs to be coupled with adequate long-term cancer control.

The “New” Prostate Cancer InfoLink concedes that these data are indeed “encouraging,” and they are suggestive of the idea that focal forms of HIFU may well be “erectile function sparing” in treatment of carefully selected men with localized prostate cancer, but …. We are going to need to see a good deal more data before we can feel confident that focal HIFU can be used consistently to meet what most men are going to see as two critical goals that need to go together:

  • Elimination of potentially clinically significant prostate cancer and
  • Documentable recovery of functional pre-treatment erectile ability

And it also needs to be clear whether this group of 118 patients included any men at all who were actually good candidates for active surveillance and therefore could have probably retained baseline sexual and erectile function for at least 12 months without any need for treatment whatsoever!


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