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

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.

Forty-six patients undergoing radiation therapy for oral/pharyngeal squamous cell carcinoma were evaluated clinically and by Candidal cultures before, during, and after irradiation.

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).

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.