Conclusion: The infiltrative growth pattern may predict tumor depth and lymph node metastasis. INF-a seems to fall into a low-risk category, and no additional treatment may be required immediately.
Objectives: Tumor depth is a predictor of lymph node metastasis in early pharyngeal cancers. An infiltrative growth pattern is also a prognostic factor in other cancers. This study aimed to elucidate the predictive role of infiltrative growth pattern in early pharyngeal cancers.
Methods: Thirty-eight lesions from 37 patients who had undergone trans-oral resection of pharyngeal cancers were included. According to the Japanese Classification of Esophageal Cancer, infiltrative growth pattern was classified into three groups; INF-a, INF-b, and INF-c. The correlation between infiltrative growth pattern and tumor depth, cervical lymph node metastasis was analyzed.
Results: Of the 38 lesions, 25 were INF-a, nine were INF-b, and four were INF-c lesions. Lymph node metastasis was observed in three INF-b and one INF-c lesions. In contrast, no INF-a had lymph node metastasis. All INF-a lesions showed shallow invasion of the sub-epithelium; INF-b and INF-c lesions had significantly greater depth than INF-a.
Keywords: TOVS; infiltrative growth pattern; lymph node metastasis; pharyngeal cancer; vessel infiltration.