Oral squamous cell carcinoma: epidemiological study and risk factor assessment based on a 39-year series.

Oral squamous cell carcinoma (OSCC) remains a challenge for head and neck surgeons, with low 5-year survival rates despite improvements in diagnostic techniques and therapies. This retrospective observational study was performed to evaluate the epidemiology and risk factors in a cohort of 666 patients with invasive OSCC over a 39-year period. Risk factors assessed were age, sex, toxic habits, premalignant lesions, tumour location and size, and neck involvement, and pathological factors such as surgical margins, tumour thickness, perineural invasion, and bone invasion. These factors were analysed over time, and their influence on recurrence and survival rates examined. Results were compared with those of current epidemiological studies in the literature. This series showed a tendency to diagnosis at older ages (P<0.001) and decreased differences in sex distribution (P<0.001) over time. Regarding risk factors, tobacco and alcohol drinking increased significantly in females, but remained stable in males. Forty percent of the patients developed recurrences during follow-up; the relapse rate did not improve over time (45.6% in the 1980s to 36.1% in 2010-2017). The 5-year survival rate also remained stable over time, ranging from 62.7% (1980s) to 71.7% (2010-2017). This epidemiological study analysed trends across four decades in a stable cohort, with results that may be extrapolated to the populations of European countries. The results confirmed that recurrence rates and survival rates have not improved over time, despite better surgical treatments and new therapies. Further studies are needed to improve knowledge about genetics and tumour behaviour in oral cancer.