Influência do tratamento antifúngico no perfil de sensibilidade de candida spp. Isoladas de pacientes submetidos à radioterapia na região de cabeça e pescoço: estudo piloto e revisão sistemática da literatura

Abstract

Oral candidiasis (OC) is one of the most frequent complications in patients undergoing radiotherapy (RT) for head and neck cancer (HNC), being favored by alterations in the oral microbiota and local immunosuppression. The recurrent use of antifungal agents has contributed to the emergence of resistant Candida spp. strains, highlighting the need for effective and safe therapeutic alternatives. Therefore, the aim of this study was to evaluate the susceptibility profile of Candida spp. isolates from patients undergoing RT in the head and neck region after antifungal treatments. This dissertation comprised two complementary studies: (1) a pilot clinical and microbiological study that evaluated the efficacy of antimicrobial photodynamic therapy (aPDT) compared to nystatin (NYS) in the treatment of OC in irradiated patients; and (2) a systematic review that investigated the influence of antifungal therapy on the susceptibility profile of Candida spp . isolated from these patients. In the pilot clinical study, both NYS and aPDT proved to be effective and safe in the management of OC, showing similar clinical responses and a reduction in fungal load, without significant changes in the susceptibility profile after aPDT. The systematic review showed that OC remains a prevalent complication in patients with HNC undergoing RT, with a predominance of Candida albicans and a progressive increase in non-albicans species (NCAS), such as C. glabrata and C. tropicalis, which are more resistant to azoles. Prolonged or prophylactic use of antifungal agents, particularly fluconazole, has been associated with the selection of resistant strains, whereas the direct impact of RT on antifungal susceptibility remains inconclusive, possibly related to local physiological and immunological alterations that favor yeast persistence. Among the evaluated therapies, voriconazole and amphotericin B showed better performance against NCAS. Controlled and standardized clinical trials are still needed to confirm the role of aPDT as an adjuvant or alternative therapy to conventional antifungal treatment in irradiated patients.