Candida prevalence in saliva before and after oral cancer treatment

Previous studies have shown an increased prevalence of candidiasis in patients receiving radiotherapy for head and neck cancer. However, little is known of the effect the different cancer treatment modalities have on the oral Candida status.

The objective of this study was to investigate the change in salivary Candida status of oral squamous cell carcinoma (OSCC) patients undergoing cancer treatment. The hypothesis was that cancer treatments change the oral microbial environment favouring an increase in the prevalence of more pathogenic non-albicans Candida (NAC).

We collected paraffin-stimulated saliva from 44 OSCC patients before surgery and after a minimum of 19 months of follow-up. Chromagar, Bichro-Dupli-test and API ID 32 C were used for identification of different Candida species and results were analysed statistically.

At both timepoints, 75% of samples were Candida positive with C. albicans being the most common yeast. NAC strains were present in 16% of the pre-operative samples and 14% of the follow-up samples. The NAC species found were C. dubliniensis, C. krusei, C. guilliermondii (preoperatively only) and C. glabrata (at follow-up only). In 73% of the cases, the salivary Candida status remained unchanged. There was an 18% increase in the prevalence of candidiasis. However, the different treatment modalities did not statistically significantly affect the Candida status of the patients.

The intraindividual prevalence of salivary Candida among OSCC patients seems to be stable and different treatment modalities have little to no effect on the salivary Candida status.