The prognostic significance of histological features in oral squamous cell carcinoma.

BACKGROUND

Different factors predict nodal metastasis, recurrence and survival in oral cancer. The aim was to assess the prognostic value of histological features related to the primary tumour.

METHODS

A total of 144 patients surgically treated at Odense University Hospital for oral cancer between 1999 and 2004 were included in the study. Postoperative radiation therapy was given in case of close and involved margins or high TNM stages (UICC 1997). Median follow-up time was 38 months. All surgical resections were reviewed and 22 histological characteristics were assessed.

RESULTS

The predominant sites were floor of mouth (FOM, 39%) and lateral tongue (35%). Fifty-nine per cent had UICC97 stage I-II disease. Five-year cause-specific survival was observed in 65%. Nodal involvement at diagnosis was observed in 36% which was significantly related to grade, neural and vascular invasion; surgical margins and increasing tumour depth. A cut-off value of 2 mm (4 mm for FOM) separated patients without and with nodal metastasis at the time of diagnosis. However, on multivariate analysis, neck disease was only associated with tumour depth and grade. Cox analysis of local recurrence in the oral cavity over time showed that tumour diameter and surgical margins were significant predictors while cause-specific survival was related to diameter, depth of invasion, surgical margins and extracapsular spread (ECS).

CONCLUSIONS

Tumour depth and grade were strong prognostic factors for nodal metastasis, independently of other histological features. Tumour diameter and margins independently predict local recurrences in the oral cavity as well as cause-specific survival. Nodal involvement and ECS were associated with adverse prognosis.