Great critque of a horrible study:http://torontophysiotherapy.ca/rehab-science-blog/is-manual-lymphatic-drainage-a-cost-effective-treatment-for-early-lymphedema/

Manual lymphatic drainage is a central tenant of Complex (Combined) Decongestive Therapy, the standard treatment for the chronic swelling condition known as lymphedema. While the benefits of manual lymphatic drainage are well recognized for cases of longstanding lymphedema, does it provide enough benefit for early cases to warrant the added cost to patients? New research sheds new light on the debate.

Early studies of lymphedema showed that when manual lymphatic drainage massage (MLD) was included as part of Complex (Combined) Decongestive Therapy (CDT) it resulted in a substantial additional decrease in swelling (ref 1). However, a more recent meta-analysis of 5 randomized controlled trials (a robust experimental methodology), suggests that the benefits MLD may be much more modest, albeit still statistically significant (ref 2). While MLD is a safe practice without known side effects, it is important to consider how much additional benefit is derived from incorporating MLD into treatment, and compare this to the added cost. The studies to date have not been sufficiently large enough, nor designed effectively enough, to draw strong conclusions.

A new Canadian study published last week sheds further light on this issue. The randomized controlled trial was designed to evaluate the benefit of manual lymphatic drainage as part of CDT for the treatment of lymphedema secondary to breast cancer (ref 3). This study improves on previous randomized controlled trials by evaluating a greater number of patients (103 enrolled, 95 completed), across multiple health centers (six). The study compared CDT (comprised of manual lymphatic drainage, compression, education, exercise and skin care) with and without the MLD component, evaluating arm volume, function and quality of life immediately following treatment, as well as at 12, 24 and 52 weeks post-treatment.

The authors concluded that, in contrast with previous studies, they were “unable to demonstrate a significant improvement in lymphedema with decongestive therapy [CDT with MLD] compared with a more conservative approach [CDT without MLD]”. This study was published alongside an opinion piece by unrelated authors that was curiously titled: “Mounting Evidence Against Complex Decongestive Therapy As a First-Line Treatment for Early Lymphedema”, and that cites these results and some of the other earlier randomized controlled trials as evidence that MLD (and not CDT as the title suggested) may not be a cost-effective strategy of first-line care for patients with early lymphedema compared with “conservative” practices (namely CDT without MLD).

So what does the data actually say about manual lymphatic drainage?

The latest study had enough patients enrolled to be able to detect a 20% or greater difference in percent arm volume reduction between the test groups with statistical confidence. Their data showed a 6% improvement in arm volume levels in favour of MLD, but accordingly this was deemed to be statistically insignificant. The authors state that a larger study size may show that the 6% difference is in fact statistically valid.

However, when the authors examined absolute volume reduction rather than volume reduction as a percentage of initial baseline volume, the benefit of adding MLD was found to be both larger and statistically significant (250ml vs 143ml of volume reduction). The reliability of this result was questioned by the authors since, by chance, the women in the MLD group had on average a larger excess baseline volume (750ml vs 624ml) than those in the control group, and so they had the potential to lose more. Although this may be a rational argument, it may also be overly simplistic: a previous study showed that patients with more mild swelling actually respond better to treatment than those with more moderate swelling (see our blog post), and hence it is possible that the small benefit of manual lymphatic drainage observed in the current study may actually be greater than what was reported. Unfortunately, when the authors attempted to use two different statistical methods to remove the excess baseline arm volume difference from the analysis they got conflicting results as to whether the resulting absolute difference was in fact still statistically significant. The authors further point out that the best measure of treatment outcomes (percentage volume or absolute volume) has not been established.

Assuming the benefit of MLD is statistically valid, it is unclear whether such differences impact patient function and/or quality of life. Participants did not report significant differences in symptoms or quality of life between the two groups over the time frame investigated. Interestingly, the authors did note that patients with lymphedema for more than one year tended to see greater benefit from CDT, although once again the study did not have sufficient statistical power to assess this trend. As the authors note, this observation supports the notion that longstanding lymphedema, in particular where fibrotic tissue has formed, may be less amenable to compression alone and may require the use of massage to help breakdown scar tissue (ref 4).

So what is the take home message from this body of work?

CDT with or without MLD provides a large and valuable benefit to patients with lymphedema. The incremental benefit of including manual lymphatic drainage is likely greater for patients with more longstanding, or advanced, cases of lymphedema, or for those who do not respond well to compression alone.

Manual lymphatic drainage is demonstrated to be a safe technique without known side effects. The major concern with incorporating MLD into the treatment of patients with early cases of lymphedema (where the relative response may be the smallest), is the cost-benefit. Namely, is the added monetary cost of providing manual lymphatic drainage worth the potentially small improvement in limb volume in these patients? As the authors point out, the cost of incorporating MLD in their study was considerable ($1500 CDN), or $13/ml of additional volume reduction. The high cost of treatment was a result of the intensive treatment protocol used: MLD was provided in five one-hour sessions per week, for a total of four weeks. It is not clear why the authors chose this course of treatment. The effective amount of MLD to achieve limb reduction has not been adequately investigated, but a number of studies have shown significant reductions with much less intensive regimens (such as in ref 5 where an average reduction of over 50% was observed in 12 treatments), with the majority of volume reduction occurring within the first two weeks of treatment initiation. While a hard-nosed dissection of treatment cost is refreshing to see, in this case it is not particularly informative. The protocol used in this study would be considered by many practitioners including ourselves to be overkill for the vast majority of patients, and especially for those with early lymphedema.

When evaluating the cost-benefit of MLD it is also important to consider the broader clinical context. While modest additional reductions in arm volume afforded by the addition of MLD to CDT for patients with early lymphedema may not have a significant impact on patient quality of life in the short term, it is worthwhile considering the progressive nature of this condition. Swelling causes cumulative damage to the lymphatic system and surrounding tissue, which exacerbates the underlying insufficiency. Having larger volumes of swelling for longer duration will cause proportionally greater damage, a downward spiral that leads to an advanced stage of lymphedema called “non-pitting lymphedema” where the swelling becomes firm and fibrotic. This advanced stage coincides with changes in tissue composition including a substantial increase in fat which can make CDT less effective, potentially necessitating more invasive procedures (see our blog post).

When taking the available research into consideration, our (admittedly biased) opinion is that the current gold standard of care (CDT with MLD) remains a prudent strategy for cases of early lymphedema, and that the detection and treatment of early lymphedema is vital.

Given the current context of health care funding in Canada, where patients pay out of pocket for lymphedema treatment, patients need to be well informed of their treatment options so that they can make the most effective use of their health care dollars. Patients should seek out CDT practitioners who are able explain the benefits of each treatment, and who will work with them to maximally attain their health goals within their budgets. In most cases much less intensive courses of MLD can be effective, and can be incorporated into sessions that provide additional therapy. In addition, patients should act proactively to decrease their risk of lymphedema in the first place (learn self-monitoring and preventative practices), and seek out CDT early on to prevent or delay progression. In one study it was reported that early intervention in mild cases could contain lymphedema at low levels for at least 10 years (ref 6). Finally, learning self-massage techniques (watch our lymphedema self-massage video) can allow patients incorporate some MLD into their daily lives at no added cost.