About one in four breast-cancer survivors eventually develops lymphedema, a painful inflammatory condition resulting from the blockage of lymphatic vessels that ordinarily drain fluid from the tissues throughout the body. While in the developed world lymphedema most often arises as an unintended consequence of radiation therapy for cancer, there are numerous other causes as well. An estimated 10 million people in the U.S. alone suffer from it.
But by the time the main symptom of lymphedema — swelling of one or more limbs — is detectable, the condition may have gotten such a foothold that it becomes difficult or impossible to reverse, at least given the treatment choices now available.
In a study just published in PLoS ONE, veteran vascular expert Stan Rockson, PhD, and his Stanford colleagues have identified a set of proteins circulating in blood whose levels accurately flag lymphedema's presence. This could make a difference. As I wrote in my release about this study:
The only known way to diagnose lymphedema now is via physical inspection, and all too often it is misdiagnosed or overlooked altogether. But the biological events underpinning this condition may be present five years or more before symptoms become evident, said Rockson. Moreover, there are no effective drugs for combating lymphedema, just costly, time-consuming and annoying physical therapy, which virtually never completely eliminates the symptoms. While physical therapy can arrest progression and reduce swelling by as much as half, the condition typically remains a long-term problem. “Lymphedema virtually never just goes away on its own,” said Rockson. Indeed, it tends to progress in severity over time, whether it is treated or not.
When I asked Rockson about the findings' significance, he told me, “A standardized, accurate bioassay for lymphedema could help to pave the road for future human clinical trials of drugs to treat it." Monitoring trial subjects at the molecular level with a lymphedema-detecting blood test could provide early evidence regarding whether an experimental treatment was working. Rockson is conducting clinical trials of pharmaceutical agents for lymphedema, and expects to incorporate the new test into those trials.
The upshot: some reason for optimism that a common but relatively neglected condition finally will be amenable to detection and, eventually, treatment with 21st-century techniques.