Commonly used chemotherapy drugs disrupt the birth of new brain cells, eventually leading to a decline in cognitive function, says a new study from University of Rochester Medical Centre.
However, researchers suggest the condition could be partially reversed with the growth factor IGF-1.
They investigated the effects of routinely used doses of cyclophosphamide and fluorouracil, paclitaxel and doxorubicin.
The study is relevant to the legions of cancer survivors who experience a frustrating decline in cognitive function after chemotherapy treatment, known as chemo brain.
"It is not yet clear how our results can be generally applied to humans but we have taken a very significant step toward reproducing a debilitating condition and finding ways to treat it," said Dr Robert Gross, professor of Neurology and of Pharmacology and Physiology at URMC and principal investigator of the study.
Chemo brain is a newly recognized condition. The URMC team found surprising data about how the four drugs impact the brain, Gross said, and they are the first to report that the experimental insulin-like growth factor, IGF-1, may be beneficial.
The study showed that all four drugs caused a significant breakdown in brain cell proliferation in the animal model.
A statistical analysis of cell regeneration showed a 15.4 percent reduction in new brain cells following fluorouracil, a 30.5 percent reduction following cyclophosphamide, a 22.4 percent reduction following doxorubicin, and a 36 percent reduction following paclitaxel.
"It could be that all of the chemo drugs cross into the brain after all, or that they act via peripheral mechanisms, such as inflammation, that could open up the blood-brain barrier," said Gross.
Administering IGF-1 prior to and following a conventional cyclophosphamide multiple-dose regimen, and a single, high-dose of cyclophosphamide showed an increase in the number of new brain cells, but was more effective in the high-dose model.
The study appears online in the journal Cancer Investigation.