Predictive value of tumor thickness for cervical lymph‐node involvement in squamous cell carcinoma of the oral cavity

Abstract BACKGROUND: Tumor thickness (TT) appears to be a strong predictor for cervical lymph‐node involvement in squamous cell carcinoma of the oral cavity (OSCC), but a precise clinically optimal TT cutoff point has not been established. To address this question, the authors conducted a meta‐analysis. METHODS: All relevant articles were identified from MEDLINE and EMBASE as well as from cross‐referenced publications cited in relevant articles. Lymph‐node involvement was confirmed and identified as positive lymph‐node declaration ( P LN D ) by either pathologic positivity on immediate neck dissection or by neck recurrence identified after follow‐up ≥2 years. Odds ratios (OR) were calculated to quantify the predictive value of TT. Negative predictive values (and the percentage of patients falsely predicted to not have P LN D [FN‐ P LN D ]) were compared to determine the optimal TT cutoff point. RESULTS: Sixteen studies were selected from 72 potential studies, yielding a pooled total of 1136 patients. Data were examined for the following TT cutoff points: 3 mm (4 studies, 387 patients), 4 mm (9 studies, 778 patients), 5 mm (6 studies, 367 patients), and 6 mm (4 studies, 488 patients). The OR (95% CI) was 7.3 (5.3‐10.1) for the overall group. The proportion of FN‐ P LN D was 5.3% (95% CI, 2.0‐11.2), 4.5% (2.6‐7.2), 16.6% (11.5‐22.8), and 13.0% (9.7‐16.9) for TT<3, <4, <5, and <6 mm, respectively. There was a statistically significant difference between the 4‐mm and 5‐mm TT cutoff points ( P = .007). CONCLUSIONS: TT was a strong predictor for cervical lymph‐node involvement. The optimal TT cutoff point was 4 mm. Cancer 2009. © 2009 American Cancer Society.