Sunday, June 5, 2011

The painfulness of pink

During my last 6 years of work, I was assigned to various pain projects. Basically, as we saw it, pain could be described in two main categories: neuropathic pain and nociceptive pain. Nociceptive pain, "good" pain is a result of normal functioning of the nervous system.. You put your hand on a hot stove and feel pain and withdraw the hand; you hit your finger with a hammer and it hurts; the cartilage between your joints wears out and your joints hurt. Although this type of pain can be controlled by various classes of drugs, such as NSAIDs that block  prostagladin synthesis and opioids, the drugs  have side effects and can be addicting.

Neuropathic pain however, we referred to as 'bad' pain and for the most part is not controlled very well by measures useful for nociceptive pain. It is thought to be due to damage of the nerves themselves. Diabetes can cause damage to the nerves resulting in numbness and pain. Fibromyalgia has a large component of neuropathic pain. What starts fibromyalgia? Who knows.

Taxol can induce neuropathic pain. Fortunately for me, it was short-lived. Three days after dosing, I would have extremely painful muscles. It would feel just as if I ran a marathon though that pain was easily eased by hot baths, relaxing and ibuprofen. Nothing would help the Taxol induced pain. I asked for gabapentin, which does relieve chronic neuropathic pain but it takes a while to kick in. Opiates helped a little. Fortunately my symptoms faded as the drug went away though for some, numbness and pain persists for years after.

For more than a year after treatment, I had fairly severe pain in the arm where I had the node removal. It was not clear if the culprit was the surgery or the radiation. Both could have injured my nerves causing them to be hypersensitive. The pain did not feel all that different from the broken bone pain I had in the opposite arm a year earlier ( which went away faster than this cancer induced pain). It also caused me to worry: was I having bone mets already? It went away, which bone mets would not.

Another source of 'pink pain' are the aromatase inhibitors (AI) that block the peripheral formation of estrogen. Women who take them experience severe bone and joint pain. It is thought that this is due to the nerves being damaged. Women are left with a gamble: do they want to decrease their chances of their estrogen positive cancers returning but experience severe pain for 5 years or take their chances with the cancer. As an added bonus, they also experience severe hot flashes and loss of libido. I whined big time when I found out I had estrogen negative BC as there was nothing past chemo I could take to prevent it from coming back but at least I was spared AI pain. So about 80% of BC estrogen positive, 160000 new cases a year in the US alone, and 5 years of these drugs are recommended. That's a whole lot of pain.

Recently I had a long talk with my former boss who now is the head of repurposing existing drugs for new indications with an emphasis on pain. I nudged him towards the neuropathic pain of cancer..please initiate some clinic trials. I gave him numbers..there would be a sizeable market. He could not tell me if he would follow through but at least it is on his radar. We'll see.

The temperature and humidity has dropped..yesterday was unbearable.
We had a nice lunch with Josh and Julia today. I am glad that we get to see them so often.

1 comment:

Teri Bernstein said...

this is so important! your discussion with your boss! You are exactly the perfect person to make this improvement happen...or at least be on the radar of people who can make it happen...for thousands and thousands of women...


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