Muscle Invasion in Oral Tongue Carcinoma as a Predictor of Nodal Status and Local Recurrence: Just as Effective as Depth of Invasion?
Katherine L Chandler, Susan Muller, Courtney Vance, Steven D Budnick. Emory University, Atlanta, GA
Background: The most important prognostic factor in patients with early head and neck squamous cell carcinoma (SCC) is the presence of disease in cervical lymph nodes. Depth of tumor invasion (DOI) is a histologic feature that consistently correlates with lymph node metastasis and since 2000, the CAP has recommended that DOI be included in pathology reports; however, there are difficulties with accurately assessing and utilizing depth of invasion. The method is fraught with inconsistencies such as where to take the measurement and what should be used as the appropriate cut-off. These difficulties are magnified in frozen sections where freeze artifact can make accurate measurement even more troublesome. Conversely, identifying tumor at or within muscle could be achieved with minimal difficulty. The aim of this study is to identify a simpler and more reproducible method of determining and reporting DOI by using skeletal muscle invasion as a surrogate marker of depth.
Design: After IRB approval, oral tongue SCC AJCC stage T1 cases were identified in the Emory Department of Pathology database. The patient clinical histories were reviewed via electronic records. 61 cases had a minimum of 2 years of clinical follow-up and were included in the study. The cases were then examined histologically to assess skeletal muscle invasion, perineural invasion, and greatest depth of invasion. The two methods of measurement were analyzed to determine the positive predictive value (PPV) of DOI or muscle invasion with both nodal disease and local recurrence. The PPV between depth of invasion and muscle invasion were compared.
|Muscle Invasion Present||Muscle Invasion Absent|
|Positive Lymph Nodes||10||1||PPV=23.3%|
|Negative Lymph Nodes||33||17|
|Depth ≥ 3||Depth < 3|
|Positive Lymph Nodes||11||0||PPV=29.7%|
|Negative Lymph Nodes||26||24|