Can a dHACM allograft really improve sexual function post-surgery?

Our attention has been brought to a recent article suggesting that use of a “dehydrated human amnion/chorion membrane” (dHACM) allograft nerve wrap around the neurovascular bundle may help with recovery of erectile function post-surgery.

The paper by Patel et al. reports data from what was basically a “pilot” or “feasibility” study in 58 patients, all treated between March 2013 and July 2014. These 58 patients all underwent a bilateral, nerve-sparing form of robot-assisted laparoscopic prostatectomy. (Note that the paper’s abstract does not state explicitly that such prostatectomies were all given for men diagnosed with prostate cancer, but it seems likely that that was the case.) Prior to their surgery, all the patients were sexually potent, with a Sexual Health Inventory for Men or SHIM score of 19 or higher, and completely continent.

It is worth noting that 25 is the highest possible score on the SHIM scale and that any man with a SHIM score of less than 22 is considered to have at least some degree of erectile dysfunction.

The dHACM allograft — which we believe was conducted using using a commercially available form of dHACM known as Amniofix — was placed around the neurovascular bundle of the prostate immediately following the full nerve-sparing robotic prostatectomy. Some of the patients were given such a dHACM allograft and some were not, and the postoperative outcomes of the patients were then compared for any effects on recovery of erectile/sexual function and continence and other relevant outcomes. However, the abstract of the paper by Patel et al. does not tell us exactly how many men did or did not receive the allograft; nor does it tell us any significant details about the patients, but we would suspect that many had low-risk prostate cancer (and so there have to be questions about how many of these patients might have done just as well — or better — on active surveillance).

Here is what Patel and his colleagues report:

  • Compared to the men who did not receive the allograft, the men who did receive the dHACM allograft had
    • No apparent increase in blood loss or increase in operative time at surgery
    • No negative oncologic outcomes (i.e., they all had their cancers eliminated)
    • Comparable recovery of continence at 8 weeks post-surgery (81 vs. 74 percent; p = 0.373)
    • Better average (mean) time to recovery of continence (1.21 vs. 1.83 months; p = 0.033)
    • Slightly better recovery of sexual potency at 8 weeks post-surgery (66 vs. 52 percent; p = 0.132) — but this was not statistically significant.
    • Better average (mean) time to recovery of sexual potency (1.34 vs. 3.39 months; p = 0.007)
    • Higher post-surgical SHIM scores at maximal follow-up (16.2 vs 9.1).

The authors basically conclude that, in this highly selected group of patients, use of the dHACM allograft “appears to hasten the early return of continence and potency” in men receiving a robot-assisted laparoscopic prostatectomy. However, we should note that, at maximal follow-up, the average SHIM score of the men who had a dHACM allograft was still (at 16.2) well below the minimum of 19 that all these patients had prior to their surgery!

We should also note that at least one surgeon in Florida who was not involved in the study by Patel et al. appears to have been using this technique for a significant period of time, but we are not aware of any published data on the successes and failures of this technique in the hands of this particular surgeon.

It is also important to note that Patel and his colleagues are expecting, soon, to initiate a much larger, randomized clinical trial (in about 230 patients) of the use of Amniofix. The stated goal of this study is the evaluation of the effectiveness of dHACM “in reducing neurovascular bundle inflammation in prostate cancer patients undergoing bilateral full nerve sparing robotic assisted laparoscopic radical prostatectomy.” To be eligible to participate in this trial, patients must be between 40 and 70 years of age, have primary prostate cancer with a Gleason score of between 6 and 9, be capable of undergoing a full, bilateral nerve-sparing operation (which implies no significant risk for extracapsular prostate cancer), and have a pre-surgical SHIM score of > 19. There are also a whole bunch of exclusion criteria (e.g., the inability to comply with penile rehabilitation, including the use of an oral 5-phosphodiesterase inhibitor like Viagra or Cialis).

It appears to The “New” Prostate Cancer InfoLink that this is a very serious attempt to see if the use of a dHACM allograft nerve wrap around the neurovascular bundle as a last step in the completion of a robot-assisted laparoscopic prostatectomy may be able to help some men with prostate cancer recover erectile/sexual function after their surgery. However, “help some men” is perhaps the important phrase. It is apparent from the available data and the proposed structure of the new clinical trial that the value of this technique is limited:

  • It will only be applicable to men who are good candidates for and can actually have bilateral nerve-sparing surgery.
  • Patients will still (almost certainly) need to combine the use of the allograft technique with the long-term use 5-PDE inhibition.
  • Even then, patients are not likely to recover the same level of erectile function as they had prior to surgery.

We look forward to hearing whether this technique really does have benefit in the setting of a randomized clinical trial, because the few data currently available are, at best, suggestive of only a small benefit in some patients who may well have been particularly good candidates for some reason or another.

Editorial note: The “New” Prostate Cancer InfoLink thanks the partner (M.O.) of a recently diagnosed patient for bringing this allografting technique to our attention.

One Response

  1. Thanks so much for looking at this, Mike. I remain very hopeful that this could be a help for some prostate cancer patients facing radical prostatectomy. Amniofix is used successfully in various surgeries now, spinal for example, and it is always exciting to learn of new approaches for known medical products.

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