Survival analysis of patients with oral squamous cell carcinoma in association with DNA of the main types of oncogenic oral viruses

Background. Morbidity and mortality from oral squamous cell carcinoma occupy a significant place in the structure of morbidity in Russia. Therefore, the search for informative prognostic factors remains an urgent task for oncologists involved in the treatment of malignant tumors of the oral mucosa. Objective. Determination of the occurrence of DNA of oncogenic viruses in the structure of oral squamous cell carcinoma and to determination of the prognostic role of the detected viruses in the survival rates of patients. Methods. A prospective study included 116 patients with newly diagnosed oral squamous cell carcinoma. In all tumor tissue samples, HSV-I, -II, CMV, EBV, HPV-6, -11, HPV-16 and HPV-18 DNA were detected using real-time PCR. The overall survival (OS) and progression-free survival (PFS) were analyzed. Results. In 54 (46.6%) patients, viral DNA was absent in the tumor structure. In the others, EBV DNA was detected significantly more often - in 40 (34.5%), and HPV(types 6, 11, 16 and 18) - in 48 (41.4%): HPV-6,-11 - in 16 (13, 8%), HPV-16 - in 12 (10.3%), HPV-18 - in 20 (17.2%). HSV-I, -II, and CMV DNA were detected less frequently: HSV-I,-II were detected in 2 (1.7%) patients, CMV - in 5 (4.3%). The median OS of virus-positive patients who underwent non-radical treatment was 15.0 months (95% CI, 12.0-27.0), virus-negative - 10.0 months (95% CI, 5.5-12,0; p=0.0049). The median PFS of virus-positive patients who underwent non-radical treatment was 6.0 months higher than that of virus-negative patients: 11.0 months (95% CI, 9.0-13.5) versus 5.0 months (95% CI, 3.0-6.0; p=0.0053). Conclusion. The analysis suggests that the presence of DNA of the considered types of viruses in the cells of oral squamous cell carcinoma may be a factor in the favorable course of the disease, increasing the survival rates of patients even after nonradical treatment program.

oral squamous cell carcinoma, Epstein-Barr virus, human papilloma virus (types 6, 11, 16, 18), herpes simplex virus (types I and II), cytomegalovirus, overall survival, progression free survival