Candidal colonization and oral candidiasis in patients undergoing oral and pharyngeal radiation therapy

Objectives. Radiotherapy-induced hyposalivation encourages oral candidal colonization that often leads to oral/pharyngeal candidiasis. The purpose of this study was to quantitate oral candidal colonization; assess signs, symptoms, and response to antifungal management, speciate Candida, and evaluate the influence of smoking and dentures. Study design. Forty-six patients undergoing radiation therapy for oral/pharyngeal squamous cell carcinoma were evaluated clinically and by Candidal cultures before, during, and after irradiation. Results. All patients complained of progressive xerostomia. There was a significant increase in the prevalence of positive candidal cultures (p = < 0.0001): baseline 43%, completion of radiotherapy 62%, and follow-up timepoint 75%. Smoking and denture wearing were not statistically significant risk factors for increased candidal colonization (p = 0.085 and p = 0.420, respectively). Eight patients developed clinical candidiasis. Although five responded clinically to systemic antifungal medication, all follow-up cultures remained positive. Candida albicans was the predominant species at baseline and completion of radiation (85% and 68%, respectively). Conclusions. When salivary glands are included in the field of radiation, xerostomia occurs, causing progressive increases in oral Candida colonization. Because 17.4% developed clinical candidiasis during radiotherapy and the question of fungal resistance remains speculative, a recommendation for the prophylactic use of antifungal medication is unresolved.