Unmet Medical Need
There is no standard or routine screening test for oral cavity, pharyngeal, and laryngeal cancer.
Late Stage Detection
Most cases of oral cancer are not diagnosed until they are in advanced stages (III or IV).
The management of late stage oral cancer is complex and often involves surgery and radiotherapy.
By contrast, small, early-stage cancers can often be treated by simple surgery, with less cost, and better medical outcomes.
The five-year survival for stage I mouth cancer has been shown to be 96% compared with 57% for late disease at stage IV.
More than half of oral cancers have already spread to lymph nodes or other areas by the time they are found.
Screening for mouth cancer: the pros and cons of a national program. Br Dent J 225, 815–819 (2018). https://doi.org/10.1038/sj.bdj.2018.918
It can be difficult to detect areas of abnormal cells just by looking at your mouth, so it's possible that a small cancer or precancerous lesion could go undetected.
The delay in detection and diagnosis of lesions is often attributed to the asymptomatic nature and the difficulty in differentiating premalignant and malignant lesions from benign conditions.