As people become more health conscious, routine medical checkups are widely carried out and imaging techniques (ultrasound and spiral CT) are improving, more and more small kidney tumors are found, but the patients themselves have no symptoms. Doctors often recommend partial nephrectomy (i.e. removal of tumor) to patients, but patients often have questions: Is it safe to remove the tumor alone? Will it recur? The literature confirms that for renal cell carcinoma less than 4 cm and limited renal cancer, radical nephrectomy and partial nephrectomy have comparable efficacy, while long-term non-tumor-specific mortality is significantly higher in the radical nephrectomy group. Long-term residual renal function assessment in patients with normal contralateral renal function suggests that the long-term advantage of partial nephrectomy is inconclusive. Another group at Cleveland Clinical Medical Center showed that 107 patients with partially resected kidney cancer had a 5-year survival rate of 88.2%, a 10-year survival rate of 73%, and 93% normal kidney function at long-term follow-up. Another group of case observations with long-term follow-up greater than 10 years showed that the incidence of renal insufficiency after partial nephrectomy and radical total resection was 2.3% and 12.4%, respectively. In conclusion, the 2014 Urological Association guidelines for the treatment of renal cancer in the United States, Europe and China recommend partial nephrectomy with preservation of the renal unit for tumors smaller than 7 cm, if available.