Clare Wilson over at the NewScientist has reported the case of a woman given an experimental stem cell treatment in Portugal for a spinal cord injury who later developed a strange tumor consisting of nose tissue. I highly recommend going over to that site and reading her excellent article.
What’s the deal with this case?
The woman was treated with nasal stem cells eight years earlier. Her condition did not improve and now eight years later the tumor was removed in the US from her spine. The 3-cm tumor fortunately was benign, but was secreting mucous and causing her pain.
More generally, providers are injecting thousands of patients each year with all different kinds of stem cells into all different kinds of places in the body. Often the stem cells have nothing to do with the place of the injury such as in this case the use of nasal stem cells for a spine injury.
There are several things to point out about this case that are particularly important.
First, there is so much we do not know about how stem cells behave when transplanted and, as George Daley is quoted in this piece, our knowledge is relatively primitive. Great caution is warranted and there are a host of risks. Professor Leigh Turner, who has been closely following emerging stem cell treatments for years, is quoted related to this point:
“But the case shows that even patients who feel they have nothing to lose should be cautious, says Leigh Turner of the University of Minnesota in Minneapolis, who tracks lawsuits involving stem cell therapies. “We still need to think in terms of risks and benefits.”
Second, long-term follow up of stem cell treatments is crucial and most of the follow up done by stem cell clinics is too short. Usually follow up outside of academic clinical trials only lasts months. This case of a benign, but harmful tumor showing up eight years after treatment shows that follow up should be measured in decades.
Third, clinical trials have risks. This was not some rogue clinic, but rather a clinical trial in Europe at the Hospital de Egas Moniz in Lisbon. Any kind of experimental treatment, even within the context of a clinical trial, has a host of risks both known and unknown.
Wilson quotes my favorite cell therapy expert, Alexey, on this point:
“The case shows that even when carried out at mainstream hospitals, experimental stem cell therapies can have unpredictable consequences, says Alexey Bersenev, a stem cell research analyst who blogs at Cell Trials. “We have to realise complications can also happen in a clinical trial,” he says.”
This case also brings to mind the case of the woman who grew bone in her eye after a fat stem cell-based interventions a few years back and also the strange, but interesting report of a doctor growing a nose intentionally on a man’s forehead to use as a replacement nose (See image above).
Stem cells are exciting and powerful, but we must do our best to understand and respect that power as clinical applications using stem cells are advanced more quickly and widely. Patients must also be made aware of the risks they are taking and the limits of current knowledge as well as alternative treatment options.