Comparison of level of circulating tumor DNA between oral squamous cell carcinoma and healthy controls: a case control study

To compare circulating tumor DNA (ctDNA) levels between patients with oral squamous cell carcinoma (OSCC) and healthy controls. A case-control study was conducted at Khyber College of Dentistry and Khyber Medical University, Peshawar. A total of 124 participants (94 OSCC patients and 30 healthy controls) were recruited using a non-probability consecutive sampling technique after obtaining the written informed consent. ctDNA was extracted from plasma and quantified using Qubit fluorometry and Nanodrop spectrophotometry. Real-time polymerase chain reaction (PCR) with TaqMan probes was used for detection. Independent t-tests compared ctDNA levels between OSCC patients and controls, and linear regression was conducted to assess the influence of age, gender, tumor site, and histopathological grade on ctDNA levels. The mean age of OSCC patients (56.82 ± 11.92 years) was significantly higher than that of controls (31.93 ± 7.10 years, p < 0.001). The most common tumor site was the buccal mucosa (20.16%), and moderately differentiated OSCC was the most prevalent histopathological grade (38.71%). The mean ctDNA level was significantly higher in OSCC cases (37.52 ± 8.71 ng/ml) compared to controls (11.00 ± 6.39 ng/ml, p < 0.001). Linear regression analysis confirmed significantly elevated ctDNA levels in OSCC cases (β = 28.13, 95% CI: 19.67–36.60, p < 0.001). Age, gender, tumor site, and histopathological grade did not significantly influence ctDNA levels. OSCC patients exhibited significantly higher ctDNA levels than healthy controls. ctDNA quantification may serve as a promising non-invasive biomarker, though further validation is needed.