Mucositis reduction by selective elimination of oral flora in irradiated cancers of the head and neck: a placebo-controlled double-blind randomized study.
OBJECTIVE
The aim of the study was to test the hypothesis that aerobic Gram-negative bacteria (AGNB) play a crucial role in the pathogenesis of radiation-induced mucositis; consequently, selective elimination of these bacteria from the oral flora should result in a reduction of the mucositis.


METHODS
Head-and-neck cancer patients, when scheduled for treatment by external beam radiation therapy (EBRT), were randomized for prophylactic treatment with an oral paste containing either a placebo or a combination of the antibiotics polymyxin E, tobramycin, and amphotericin B (PTA group). Weekly, the objective and subjective mucositis scores and microbiologic counts of the oral flora were noted. The primary study endpoint was the mucositis grade after 3 weeks of EBRT.


RESULTS
Seventy-seven patients were evaluable. No statistically significant difference for the objective and subjective mucositis scores was observed between the two study arms (p = 0.33). The percentage of patients with positive 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 support the hypothesis that these bacteria play a crucial role in the pathogenesis of mucositis.
Wijers
O B
OB
Department of Radiation Oncology, University Hospital Rotterdam-Daniel, The Netherlands.
Levendag
P C
PC
Harms
E R
ER
Gan-Teng
A M
AM
Schmitz
P I
PI
Hendriks
W D
WD
Wilims
E B
EB
van der Est
H
H
Visch
L L
LL
D000328:Adult; D000368:Aged; D000666:Amphotericin B / Q000627:therapeutic use; D003091:Colistin / Q000627:therapeutic use; D004311:Double-Blind Method; D004359:Drug Therapy, Combination / Q000627:therapeutic use*; D005260:Female; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000187:drug effects / Q000382:microbiology* / Q000528:radiation effects; D010919:Placebos; D011832:Radiation Injuries / Q000209:etiology / Q000382:microbiology / Q000517:prevention & control*; D012469:Salivary Glands / Q000528:radiation effects; D013280:Stomatitis / Q000209:etiology / Q000382:microbiology* / Q000517:prevention & control*; D014031:Tobramycin / Q000627:therapeutic use
D010919:Placebos; D000666:Amphotericin B; D014031:Tobramycin; D003091:Colistin