Anti-H.pylori Therapy Cures MALT Lymphoma in H.pylori-Negative Patients. Hmmmm
We've defended a few gastric lymphoma cases in which the alleged cause was benzene exposure. The discovery that Helicobacter pylori was was the cause of most instances of the disease made the litigation go away. Nevertheless there have continued to be cases of MALT lymphoma in patients without evidence of H. pylori infection. Could their cancers have been caused by something besides a bacteria?
In "Treatment Outcome of Localized Helicobacter pylori - Negative Low-Grade Gastric MALT Lymphoma" the authors report on what happened when they treated some MALT lymphoma patients who had no evidence of H. pylori infection with anti-H.pylori antibiotics. Complete remission was achieved in each case.
The authors offer the following hypotheses about why giving people a drug to kill a particular strain of bacteria that they don't have that bacteria might nevertheless cure them of lymphoma: (1) a first cousin, H. heilmannii, might actually be the causative organism; (2) unknown bacterial agents susceptible to the antibiotics caused the lymphoma; (3) H. pylori at populations too small to be detected are still enough to cause lymphoma; and, (4) antibiotics eradicate MALT lymphoma not by simply killing H. pylori but rather by altering the resident immune system - resetting the system as it were.
Unless the answer is (3) MALT lymphoma will serve as yet another example of the fact that, save for very rare instances like pleural mesothelioma and erionite, "but for" causal attribution in cancer cases is exceedingly difficult.
