The effects of hydrogen peroxide on brain and brain tumors.

Background: Hydrogen peroxide (HP) is routinely used during neurosurgical procedures to augment hemostasis after intracranial tissue resection. Elsewhere in the body, HP is used to kill resection margin tumor cells; in vitro studies support these clinical uses. The effects of HP on brain and brain tumors have not been evaluated. In this study, the in vitro and in vivo effects of HP on both rat and human brain parenchyma and brain tumors were examined.

Methods: Antitumor activity of varied concentrations of HP (0-30%) on cultured primary and metastatic brain tumors (n = 13) was compared with the effects of various concentrations of ethanol (0-50%). Studies were performed in rats to characterize HP-induced tissue changes that occurred when HP-soaked pledgets were placed on the arachnoid surface and along resection margins (n = 5). Additionally, the effect of HP on human brain along tumor resection cavities was investigated (n = 10).

Results: While HP demonstrated concentration-dependent tumoricidal effects in vitro, similar to results achieved with ethanol, HP caused significant injury to arachnoid and stroma with neuronal and glial injury to a depth of 1 mm in rats. Three percent HP-soaked pledgets placed in resection cavities of excised brain tumors induced similar injury in human brain.

Conclusion: HP irreversibly damages mesothelial and neural tissue. Although HP appears to have tumoricidal effects in vitro, it should be used with caution in humans because of risks of collateral injury to surrounding normal brain. HP may prove most beneficial for discrete lesions, such as pituitary tumors and metastases.