Mucositis reduction by selective elimination of oral flora in irradiated cancers of the head and neck: A placebo-controlled double-blind randomized study

Purpose: The aim of the study was to test the hypothesis that aerobic Gram- negative bacteria (AGNB) play a crucial role in the pathogenesis of radiati on-induced mucositis; consequently, selective elimination of these bacteria from the oral flora should result in a reduction of the mucositis, Methods and Materials: Head-and-neck cancer patients, when scheduled for tr eatment by external beam radiation therapy(EBRT), were randomized for proph ylactic treatment with an oral paste containing either a placebo or a combi nation of the antibiotics polymyxin E, tobramycin, and amphotericin B (PTA group). Weekly, the objective and subjective mucositis scores and microbiol ogic counts of the oral flora were noted. The primary study endpoint was th e mucositis grade after 3 weeks of EBRT. Results: Seventy-seven patients were evaluable. No statistically significan t difference for the objective and subjective mucositis scores was observed between the two study arms (p = 0.33). The percentage of patients with pos itive cultures of AGNB was significantly reduced in the PTA group (p = 0.01 ). However, complete eradication of AGNB was not achieved. Conclusions: Selective elimination of AGNB of the oral flora did not result in a reduction of radiation-induced mucositis and therefore does not suppo rt the hypothesis that these bacteria play a crucial role in the pathogenes is of mucositis. (C) 2001 Elsevier Science Inc.