Predictive factors of occult metastasis and prognosis of clinical stages I and II squamous cell carcinoma of the tongue and floor of the mouth

The incidence of occult neck metastasis in early stage tumours of the tongue and floor of the mouth varies from 20% to 30%, and the survival rates in 5 years from 73% to 97%. This study analyzes the rates of occult metastasis and prognostic factors for clinical stages I and II squamous cell carcinoma of the tongue and floor of the mouth. The records of patients with squamous cell carcinoma of the tongue and floor of the mouth, without prior treatment and treated by surgery between 1965 and 1998 were reviewed. All cases were re-staged and the surgical specimens were reviewed. This study included 193 patients, 145 men (75.1%), with ages ranging from 29 to 89 years old (mean, 60 years). The tumour site was the tongue in 132 cases (68.4%), the floor of the mouth in 45 (23.3%) and both in 16 (8.3%). With regard to stage, 85 cases were at clinical stage I (44.0%) and 108, clinical stage II (56.0%). One hundred and seventeen patients (60.6%) were submitted to a neck dissection and 27 (23.1%) had metastasic lymph nodes (pN+). The only factor associated with the presence of occult metastasis for all patients was the presence of muscular infiltration ( p=0.020); for tongue tumours the presence of vascular embolization ( p=0.043) and the presence of desmoplastic reaction ( p=0.050); for floor of the mouth tumours and T2 tumors, the histological grade ( p=0.025 and p=0.035, respectively). Disease-free survival in 5 years was 66.4% and overall survival in 5 years 68.5%. The only factor associated with disease-free survival was the presence of muscular infiltration ( p=0.019) and with overall survival were gender ( p=0.002) and clinical stage ( p=0.031). Tumours of the tongue and floor of the mouth in the initial stages, which had muscular infiltration showed a higher probability of occult metastasis and lower disease-free survival; T2 tumours showed a worse survival as did patients of the male gender.