Log in to post a reply
Mar 9, 2014 10:07AM
bluefox, I read the ILF document this morning, and it's a great resource. I found the discussion to be an objective review, including the article written by Drs. Chang and Suomi, microsurgeons at MD Andersen. I've watched presentations by a few microsurgeons doing LVA and node transfers, and those presentations have not generally been balanced. In one case, I thought I was listening to a marketing spiel. But the Chang and Suomi article presents the surgeries as having good promise for the future, and they explain why that is. But they also acknowledge that there's limited evidence to date on efficacy, and more work is needed to establish that.
Dr. Cormier's review of all the published evidence to date is very well done. She did her work under the auspices of the American Lymphedema Framework, part of a larger project that the ALF is undertaking to sort through all kinds of LE studies, to identify those whose study designs meet a high standard of evidence.
To me, the biggest limitation she cites from the body of evidence is that absent random controlled trials, most of the studies to date have the weakness of selection bias.
Here's what she says about that:
In addition, the published studies are primarily observational studies which do not include comparison groups. The reported success of many of the surgical procedures for the treatment of lymphoedema was likely strongly inﬂuenced by the selection of patients which was not well deﬁned in the majority of studies. Randomised clinical trials are designed to compare treatment arms among patients with similar characteristics. The primary advantage of randomised controlled clinical trials is to eliminate patient selection bias, which ensures that the ﬁndings and outcomes of the study can be attributed to the procedure or treatment itself rather than to the more favourable characteristics in a particular group of patients.
In other words, there's no way to identify the range of patients for whom the various surgeries might be effective, because the surgeons pre-selected their patients to maximize effectiveness of the surgeries. Now, if I were a surgeon, I'd want to pre-select too...of course they don't want to perform a surgery that's not likely to work for a particular patient. And as a patient, I'd want to make sure I'm a very good candidate for the surgery. So there's not an inherent criticism of how the microsurgeons have chosen their patients, only that their approaches to date have not provided the kind of evidence that can be generalized. Dr. Cormier's review discussion ends with the conclusion that additional studies are required to select appropriate patient populations who would derive the greatest beneﬁt from surgery.
I was surprised to see how many patients were included in the Campisi LVA study (1,800) and that follow-up was 120 months. His reported limb volume reductions are very impressive, too. His study is large and long, and he also used water displacement as his measurement technique, the gold standard. These study characteristics are great, although the study has the same selection-bias problem Dr. Cormier mentions.
What I see here is a genuine quandary for doing random controlled trials on these surgical techniques. Would it be ethical to randomly assign a group of LE patients to LVA (or node transfer for that matter) without pre-screening to ensure a probable benefit? There needs to be benefit to balance surgical risks, so I don't see that happening. Also, I wonder how extensive insurance coverage is for these surgeries, which also would seem to restrict its application to a general population of LE patients. I'm pretty sure that at the September NLN research conference, there will be one or more presentations on surgical solutions. Last time, there was a fascinating point/counterpoint debate, and I hope they'll do that again, using information from and inviting surgeons who have performed these more recent surgeries.
To anyone considering one of the LE surgeries, I highly recommend the ILF resource that bluefox linked to. Use her link to the ILF website, then go to 'resources.' It says 'click if you want to purchase' but it's a free resource that will download after you click..no payment required.