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br Acknowledgements This study was funded the Irish Departme
Acknowledgements
This study was funded the Irish Department of Agriculture, Food and the Marine through the research program FIRM/RSF/CoFoRD (Reference: 13 F 462). The authors declare no conflict of interest.
Introduction
Radiotherapy (RT) is one of the major treatment methods among patients with head and neck malignancies. RT in such cases increases oral fungal colonization, which may lead to significantly increased rates of oral fungal infections. Oropharyngeal candidiasis (OPC) is the most frequent cause of morbidity in these patients that began by a stage of colonization of the Candida on the oral mucosa. OPC is manifested by various symptoms such as pseudomembranous (thrush), erythematous and angular cheilitis. OPC creates painful infection that may expand to inner sites such as esophagus, leading to life-threatening systemic infections [1], [2].
Candida species are commonly present as normal oral caffeic acid receptor in humans. Any variation in physiological and pathological conditions, particularly after RT in patients with malignancies, may cause the yeast to switch to its pathogen type. Studies shown that among the Candida species, C. albicans is the most important species (>80%) that causes OPC. Also non-albicans species are known to be contributed in OPC in patients with head and neck cancer [3]. The possibility of oral fungal colonization can increase up to 74.5% during RT. This increase in percentage of colonization mostly occurs immediately after RT (71.4%). The use of tobacco can also increase the risk of colonization and fungal infection during RT [4], [5].
Recent studies have shown that the sensitivity of Candida spp. to certain antifungal agents, especially azoles, is decreasing which is due to their extensive use as prophylaxis in cancer patients; this leads to high incidences of ineffective treatments [6], [7].
There are few studies regarding to OPC in head and neck cancer patients who are treated by RT in Iran. Here, we studied 54 patients with detectable OPC among head and neck malignancy patients who had been treated by RT in the major cancer treatment institute in Tehran. This study was conducted to identify Candida spp. causing OPC, to determine their antifungal susceptibility pattern and pathogenic characteristics among the head and neck cancer patients in Iran. Our data can help to use more effective strategies in antifungal treatments and to design an appropriate prophylaxis program for the benefit of such patients.
Materials and methods
Results
Discussion
Oropharyngeal candidiasis is the most common oral clinical manifestation of Candida spp. in patients with head and neck malignancies [1], [2]. Since there are a few studies about Candida species that associated in OPC in Iranian head and neck cancer patients, the present study was carried out to evaluate the OPC in these patients and to investigate the correlations among sex, age, yeast species and some other relative factors. Dahiya et al. have reported that the prevalence of OPC in patients with head and neck malignancies receiving RT is 7.5%, 37.4% and 32.6% for pretreatment, during treatment and after RT stages, respectively [5]. In the present study, out of 160 head and neck patients after RT, 54 cases (33.75%) had obvious clinical sings of OPC. In our study, the prevalence of OPC in male patients (72.22%) was higher than in female (27.77%) ones (Table 2). Due to difficulty in differentiation of pseudomembranes candidiasis from mucosal reaction after RT, there is no distinct value for the incidence of oral candidiasis in the literatures [17]. In a similar study, OPC has been determined by the major criteria including clinical signs, direct microscopic test and positive response to antifungal [18]. Here, we used ITS sequencing method as a molecular-based method that is widely used for detection and identification of fungal elements in various samples. It is able to recognize Candida isolates, which is not possible by traditional identification methods [19].