Abstract
Abstract
Background: Oral cancer (OC) and oropharyngeal cancer (OPC) make up 2-4% and 2%, respectively, of all cancers diagnosed in New Zealand. Late-stage diagnosis OC and OPC (Stage III or IV) is associated with 5-year survival rates ranging from 20% to 50%, depending on the site. In contrast, the prognosis of patients treated at an early stage (stage I or stage II) is a 5-year survival rate ranging from 60% to 80%. There is currently no non-invasive method or effective screening procedure available to diagnose oral and oropharyngeal cancer at the earliest stages when survival rates are higher.
Aim: This study aimed to show if Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy when applied to saliva samples, may be used as a sensitive, non-invasive, low-cost technique to screen for and diagnose OC and OPC at an earlier stage and thus increase the likelihood of survival, as well as observe the changes in saliva composition for cancer samples before and after cancer treatment.
Methods: Unstimulated whole saliva samples were collected from 8 individuals with OPC or OC and 8 healthy individual controls. The prepared samples were used to generate FTIR spectra within the wavenumber range of 400 cm-1 to 4000 cm-1. Infrared spectra of the whole saliva for the healthy individuals (HI) and the cancer samples, before treatment (B-OC) and after treatment (A-OC), were compared for significant difference. Analysis was conducted for original average spectra data and Fourier deconvoluted average spectra data. Second derivative analysis was also used to identify peaks of interest, and curve-fitting analysis was carried out on the deconvoluted spectral data in order to identify differences between the intensities of the deconvoluted peaks and to identify differences between areas under the peaks of interest for the three groups.
Results: No significant differences were detected between HI and B-OC groups for any of the analysis methods however, for the deconvoluted spectral data of the B-OC and A-OC groups, a significant difference (p<0.05) was noted for the wavenumber 524cm-1 when the area under peaks and intensity of wave peaks were studied.
Conclusion: There was no identifiable difference in the HI and OC/OPC groups prior to oncology treatment thus suggesting that ATR-FTIR spectroscopy was not able to discriminate between these two groups.
The only significant differences noted in the saliva of OC/OPC cancer participants was after the cancer group received surgery or chemotherapy and radiotherapy, confirming the significant impact that cancer therapy has on saliva. Further analysis of FTIR spectroscopy when applied to saliva of OC and OPC patients needs to be carried out.