Oral submucous fibrosis transforming into squamous cell carcinoma: a prospective study over 31 years in mainland China.

ABSTRACT

OBJECTIVE: Oral submucous fibrosis (OSF) is an oral mucous disease caused by betel quid chewing. It is controversial whether OSF can transform into oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: In this prospective study, a group of 567 patients with OSF were enrolled from 1986 to 2017 and followed-up until 2019. The cancerous information was collected and analyzed. RESULTS: OSF transformed into OSCC in 32 cases (32/567, 5.6%). The patient's age ranged from 20 to 69 years, and the average age was 52 years. The time taken for transformation ranged from 2 to 24 years, the average being 8.6 years. The cancerous transformation occurred in 18 patients (56%) from years 2 to 9, in 13 patients (41%) from years 10-19 and in 1 patient (3%) from 24 years. We analyzed the betel quid chewing habits and found all 32 patients with OSCC-chewed betel quid. Betel quid chewing was most prevalent in patients aged 40-69 years. Sixteen patients had chewed betel quid for 10-19 years (16/32, 50%) and 19 patients (60%) chewed 10-19 slices each day. The OSCC was located in the left or right buccal regions in 23 patients (23/32; 72%) and in the left or right lingual regions in 4 patients (4/32; 12%). Well, moderately and poorly differentiated squamous cell carcinoma was present in 23 patients (23/32; 72%), 4 patients (3/32; 9%), and 5 patients (5/32; 16%), respectively. CONCLUSION: Our findings supported that OSF is a real oral premalignant disorder. CLINICAL RELEVANCE The long duration of the transformation from the OSF to OSCC suggests more frequent examinations and corresponding treatments are necessary for OSF patients.