Clinical features of microinvasive stage I oral carcinoma

Background:  This study aimed to analyse a case series of microinvasive (tumour thickness <4 mm) stage I oral squamous cell carcinoma (OSCC), with an emphasis on the clinical features of the tumours. Methods:  In total, 32 microinvasive and 67 non-microinvasive stage I lesions, which had been surgically treated, were retrospectively studied and compared. The data analysed included gender, age, risk habits, clinical appearance, lesion site, symptoms, nodal involvement and outcome. Results:  The clinical features of microinvasive lesions meant that, more often than not, they resembled premalignant lesions (P = 0.008), and diagnosis was mainly based on accurate clinical examination rather than the presence of symptoms (P = 0.029). During a median follow-up of 4.5 years, one nodal involvement and one cancer-related death were observed in patients with microinvasive lesions. A significantly higher (P = 0.044) level of nodal involvement was observed in the non-microinvasive lesion group. Conclusions:  Stage I OSCC has a favourable prognosis overall, but nodal recurrence is more common in non-microinvasive cancers. As microinvasive lesions tend to present clinically as premalignant lesions, accurate clinical examination is essential if misdiagnosis of early lesions is to be avoided.