The degree of differentiation of cancer is mainly divided into undifferentiated, hypodifferentiated, moderately differentiated and highly differentiated. The lower the degree of differentiation, the higher the malignancy of cancer, and undifferentiated cancer is the most malignant. Undifferentiated and hypodifferentiated cancers are more prone to distant metastasis, and even after surgical resection, recurrence and metastasis may occur, and the chance of such recurrence is higher than that of moderately differentiated and highly differentiated cancers. Therefore, even for early stage tumors, patients with undifferentiated and hypofractionated tumors need adjuvant chemotherapy after surgery, which can reduce the chance of recurrence and metastasis in the future. Undifferentiated and hypofractionated tumors are a factor of poor prognosis for postoperative patients.