GBS and cancer

September 14, 2008 at 7:50 pm

I did some looking into this topic because of interest and because there was some concern that I might have bone marrow cancer (multiple myeloma) when I first got sick. There are a couple of papers that indicate that the risk of cancer is greater in people that also have/will get GBS. The best paper is by Vigliani and coauthors, Journal of Neurology, 2004, vol 251, p 321. They looked at a group of people with an acute peripheral neuropathy (of otherwise unknown cause) diagnosed with cancer 6 months earlier or later than the peripheral neuropathy diagnosis. They used a strict criteria for GBS/AIDP. They found the relative risk of someone having cancer with GBS to be 2.4 compared to someone without GBS. This means that a person has 2.4 times the risk of cancer if they have GBS. The numbers are small–they looked at 435 people with acute neuropathy and found 9 cases of cancer diagnosed in this interval. It is important to note that the confidence interval for the relative risk did not include 1 meaning that even with two rare events (cancer and GBS) in a study of 400+ people, there was a greater risk of having cancer if you had GBS than expected in the population.

Another paper was Antoine and coauthors, Journal of Neurology Neurosurgery and Psychiatry, 1999, vol 67, p 7. They found that 6% of people with GBS also had cancer although the criteria were not as rigorous as in the above.
It is worth noting that the kind of cancer is very variable (Hodgkins, lung, CLL, kidney, GI, head and neck, plasma cell dyscrasia/multiple myeloma, other carcinomas and lymphomas, etc.) and the course of the GBS and cancer may be distinct. This argues that the association is more likely a problem in the immune system being the cause for both (reduction in immune surveillance predisposing to cancer and alteration in immune regulation dredisposing to the autoimmune neuropathy). The other theory proposed is that a new protein made by the cancer might predispose to the autoimmune neuropathy by having a similar protein on the nerves. When the body tries to fight the cancer, it also ends up attacking the nerves because of the similarity. It is harder to argue this if there are a number of different cancers that are associated with GBS.