Disparity in pathologic and clinical lymph node staging in oral tongue carcinoma. Implication for therapeutic decision making.

Regional lymph node metastasis is the most reliable predictor of treatment outcomes for patients with squamous cell carcinoma of the oral tongue (SCCOT). A recent American Joint Committee on Cancer staging update of malignant melanoma has incorporated pathologic lymph node staging. The authors hypothesized that pathologic lymph node staging (pN) would be a more reliable predictor of treatment outcomes than clinical lymph node staging (cN). The authors retrospectively reviewed 266 patients who received primary surgical treatment for SCCOT, including a neck dissection, from January 1980 to December 1995. Overall and disease-specific survival and disease-free interval were compared with respect to clinical and pathologic lymph node stages. Statistically significant survival differences were identified for both clinical (cN0-cN2) and pathologic lymph node stages (pN0-pN2). However, survival and disease-free interval differences for pathologic lymph node staging reached higher statistical significance (P < 0.0001) than for clinical lymph node staging (P < 0.002). This disparity can be explained by stage migration (i.e., patients with cN0-1 disease have a more advanced lymph node stage at the time of pathologic review compared with patients without cN0-1 disease). The authors found a 34% rate of occult lymph node disease in the cN0 group (19% of occult lymph nodes had extracapsular spread [ECS]). Similarly, 43% of cN1 patients had a higher stage than pN2b disease and 50% had ECS. Pathologic lymph node staging, based on a staging or therapeutic neck dissection, should be considered for patients treated for SCCOT to identify high-risk patients who may benefit from additional adjuvant therapy. Prospective studies are essential to validate these findings before pathologic lymph node staging is included in standard staging criteria.