Can Ki-67 Predict Recurrence of N0 Squamous Cell Carcinoma of the Tongue?

Objectives: Ki-67 is a molecular marker of cellular proliferation that predicts prognosis of some head and neck tumors. Studies of Ki-67 in oropharyngeal cancer have yielded conflicting findings. This study was designed to test Ki-67 as a marker for poor prognosis in NO tongue squamous cell carcinoma. Methods: We examined 29 cases in a retrospective cohort to test the hypothesis that a high rate of tumor cell proliferation (high levels of Ki-67 staining) at the invasive edge of NO squamous cell carcinoma of the tongue correlates with increased risk of recurrence. Results: There were 14 cases of recurrence. The average age of the patients with recurrence was 58 years. The average time to recurrence was 13.1 months. A 0% to 33% uptake of Ki-67 at the tumor's leading edge was associated with a 6-times-greater risk of recurrence. The mean length of survival for the group with 0% to 33% uptake was 21 months; for the group with >33% uptake, it was 33 months. Overall uptake of Ki-67 and histologic grade did not correlate with risk of recurrence. Conclusions: In this sample, low rates of Ki-67 staining at the invasive edge of the tumor predicted a risk of recurrence. These results need to be confirmed before Ki-67 can be used for predicting recurrence of tongue squamous cell carcinoma.