Squamous cell carcinoma of the oral cavity: a clinicopathologic scoring system for evaluating risk of cervical lymph node metastasis.

A series of 126 cases of squamous cell carcinoma of the oral cavity with neck dissection was studied. Several clinicohistologic parameters and statistical correlation with lymph node metastasis were evaluated. Statistical association with metastasis was found in the following factors: microvascular invasion (P < 6 x 10(-7)), grade of differentiation (P < .0001), T category (P = .003), tumor thickness (P = .005), inflammatory infiltration (P = .011), tumoral interphase (P = .02), and perineural spread (P = .04). We designed a scoring system based on statistical results that eliminates the need for complex mathematical formulas. We tested this scoring system; cases with scores ranging form 7 to 12, 13 to 16, 17 to 20, and 21 to 30 points showed metastasis in 0%, 20%, 63.6%, and 86.3% of cases, respectively. The differences between these four groups in relation to rate of metastasis were very significant (P = 8 x 10(-9)). In conclusion, this scoring system is a reliable method of predicting risk of metastasis.