There are no characteristic manifestations of kidney tumor. A few patients may show manifestations such as hematuria and lumbar pain, or even feel the mass in the stomach, which usually indicate that the tumor has entered advanced stage. At present, with the improvement of people’s living standard and health awareness, most kidney tumors are found during medical checkups. Since kidney tumors are mostly malignant tumors, once they are found, they usually need active treatment, and surgical resection is the most common treatment. In a few cases, such as patients with poor health condition, combined with many other diseases, cannot receive surgical treatment, or some patients do not want to treat actively and choose to observe. How will the tumor develop in this case? The development of renal tumor is highly related to the size and pathological type of the tumor when it is found. The change of tumor size is closely related to the initial size, for example, a tumor of 2cm in diameter doubles to directly 4cm in diameter with 8-fold volume growth; a tumor of 4cm in diameter doubles to 8cm in diameter with 8-fold volume growth as well, but there is a huge difference between the actual volume growth of 8-fold growth of 2cm and 8-fold growth of 4cm. Small kidney tumors (less than 4 cm) usually grow slowly, with an average annual growth of less than 4 mm, while large tumors grow faster, with an average annual growth of up to or even more than 1 cm. kidney tumors are mostly malignant, may metastasize and are life-threatening, and therefore require active treatment, and there is not much information on long-term observation without active treatment. It is important to note that although small kidney cancers grow slowly, nearly 2% of patients with high malignancy develop life-threatening tumors that metastasize. Therefore, even if the kidney tumor is small, it should not be ignored and needs to be treated as early as possible if it grows rapidly.