A Study on Subsite-specific Prevalence of Candidiasis in Head and Neck Cancer Patients and its Antifungal Susceptibility Pattern: A Cross-sectional Study

Abstract

Introduction: The incidence of candidiasis can vary across various subsites within the head and neck region and is associated with various co-morbidities and risk factors. The increase in the incidence of resistant Non-albicans Candida (NAC) species among these patients and the limited number of available antifungal agents make treatment difficult. A better understanding of the subsite-specific prevalence of candidiasis and its antifungal susceptibility is crucial in enhancing effective control and treatment. Aim: To determine the subsite-specific prevalence of candidiasis among Head and Neck Cancer (HNC) patients undergoing radiotherapy. Materials and Methods: A cross-sectional study was conducted on patients undergoing therapy for head and neck malignancies at the Department of Radiation Oncology, Amala Institute of Medical Sciences, Thrissur, Kerala, India over a four-year period (January 2019 to December 2022). A total of 276 patients aged 18 to 85 years with squamous cell carcinoma were included. Oral samples were collected from patients who developed candidiasis, and co-morbidities and risk factors were documented. Candida species were isolated and identified. Antifungal susceptibility was determined using the VITEK system, and fluconazole susceptibility was compared with the standard disc diffusion method. Data were entered into an Excel sheet and analysed using Statistical Package for the Social Sciences (SPSS) software. Results: Pharynx was the most frequent site of head and neck malignancy, accounting for 104 cases (37.7%), followed by the oral cavity with 83 cases (30.1%). Among patients with malignancies in the pharyngeal region, a high rate of Candida infection was observed in 42 (43.3%) out of 97 cases. Candida species isolated included C. albicans (56, 57.7%), C. tropicalis (26, 26.8%), C. krusei (8, 8.3%), C. glabrata (3, 3.1%), and C. parapsilosis (4, 4.1%). Sixty-five patients (23.5%) had diabetes, which was statistically significant (p-value <0.05). All C. albicans strains were sensitive to fluconazole. The Minimum Inhibitory Concentration (MIC) of voriconazole was very low for all tested Candida species. Conclusion: Patients with pharyngeal and oral cavity carcinomas are at an increased risk of developing candidiasis during radiotherapy. Diabetes is significantly associated with candidiasis. While C. albicans was the most common species isolated, a significant number of NAC species were also identified. Voriconazole exhibited low MIC values for C. krusei and C. glabrata, suggesting its potential as an alternative treatment option. Obtaining VITEK system identification and susceptibility reports is advisable for borderline values that may not be evident using conventional disc diffusion methods.