Chemotherapy is a common contributor to peripheral neuropathy, and because of this, there have been efforts to both prevent and treat chemo-induced peripheral neuropathy (CIPN). However, much of the work in this field has been hampered by difficulty in measuring this, as well as trials that are pretty small.
A couple have been the subject of trials that were negative, showing no benefit for the investigational agent, including the radioprotectant amifostine, the calcium channel blocker nimodipine, and some others.
A few have had some mixed and some positive results. Among these, vitamin E has been suggested in trials to reduce the frequency and severity of CIPN, but as an anti-oxidant, there is some concern that it may compromise the effectiveness of chemotherapy. Others that have looked favorable in small studies have included glutamine, glutathione, N-acetylcysteine, and calcium and magnesium infusions, though the last have raised some questions about being associated with reducing the efficacy of chemotherapy. Overall, with most of these being such small trials, and without establishing that prevention of neuropathy occurs without a compromise of the effectiveness of the chemotherapy, none of these has become a standard treatment. In the meantime, there are ongoing trials looking at whether certain approaches prevent CIPN, including acetyl-L-carnitine, vitamins B6 and B12, and alpha lipoic acid.
Beyond attempts at prevention, there are no agents that are established and FDA-approved as treatments for CIPN once it has developed. However, there are several treatments that are used for the “positive” symptoms of pain and hypersensitivity, though none is felt to be effective for the “negative” symptoms of numbness and weakness (here, positive refers to symptoms of something superimposed on top of what is normal, and negative refers to something missing from what is normal). The agents most commonly used here are Neurontin (gabapentin), Lyrica (pregabalin), opioids like oxycodone or morphine or Ultram (tramadol), a local anesthetic like Lidoderm (lidocaine) patches, or antidepressants like Cymbalta (duloxetine) or Elavil (amitriptyline), though these haven’t all been shown to be extremely effective in trials. The links go to representative studies that support their use for neuropathy. In general, these are started at low doses and titrated upwards gradually, and these are sometimes combined.
Finally, there are even approaches using electrical nerve stimulation, often with an implanted device. These approaches typically entail the involvement of specialist in managing chronic pain.
Obviously, this is a very large topic, and many of the drugs covered here could be the subject of their own post about their possible role in managing neuropathy, though this work is really also outside of my range, or that of most oncologists. For now, there are certainly several treatments that may be tried, and it’s important to note that larger trials are being conducted that we hope may lead to results that could allow us to mitigate the unfortunate effects of several of our more important and effective chemo agents.
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Posted on October 11, 2009 at 7:39 pm
Dr. West,
You probably are aware of it, but there is a study currently on-going, and looking for participants, for chemotherapy induced peripheral neuropathy. Bastyr University, in collaboration with Whidbey Island General Hospital, Skagit Valley Oncology Center, and Bastyr Integrative Oncology Research Clinic, is studying the potential benefits of acupuncture in treating CIPN.
I was surprised to find that Bastyr opened an Oncology Center this past February. I think this could be a great interest to some survivors in the Puget Sound area - and perhaps a source for an interesting visiting fellow for Grace? They are also doing a matched controlled outcome study with Fred Hutchinson Cancer Research Center on survival and quality of life for cancer survivors.