For localized renal cancer, major guidelines recommend surgical treatment [8, 9], including radical nephrectomy and partial nephrectomy, as well as active monitoring or radiofrequency ablation. Nephron-sparing surgery is preferred because of its advantages in protecting renal function . In 2006, partial nephrectomy became the gold standard in the treatment of stage T1 tumors . According to China's seventh population census, the number of people aged 60 or over was 264.02 million, accounting for 18.7%. This was an increase of 5.44% compared with 2010, indicating that the degree of aging has further deepened. In addition, the proportion of kidney cancer in the elderly population has further increased.
Although EORTC 30904  suggested that patients undergoing radical nephrectomy had improved survival, some studies supported elderly patients undergoing nephron-sparing surgery . Thus, the advantages of the two surgical methods remain controversial. For elderly patients, it is not clear how to choose between the two surgical methods and whether partial nephrectomy is beneficial [14,15,16]. Therefore, the choice of surgical method depends on patient characteristics and the functions of various organs , especially for patients over 75 years old. Additionally, the expected survival of patients and the possible complications caused by surgery that may affect the quality of life of patients should also be assessed.
Previous studies suggest that there are more complications associated with basic diseases, such as hypertension and heart disease, in elderly patients over the age of 70. However, there were no significant differences in operative time, blood loss and perioperative complications between patients under the age of 70 and patients undergoing laparoscopic radical nephrectomy. The incidence of intraoperative complications was 2.9% and 5.3%, respectively, and the incidence of postoperative complications was 8.8% and 4.2%, respectively. In comparison, the incidence of postoperative complications was higher in patients over 70 years old of age .
Berdjis et al.  conducted a study on 115 renal cancer patients over 75 years old and 908 patients under 75 years old who received surgical treatment. The finding was that age is not a contraindication for surgery. Overall complications and mortality of patients over 75 years old showed no significant difference compared with those under 75 years old, but most of them were radical nephrectomy, and partial nephrectomy accounted for only 13.4%. Staehler et al.  analyzed 117 patients with renal cancer who underwent surgical treatment and found that the incidence of perioperative complications of partial nephrectomy and radical nephrectomy was 12% and 15%, respectively, and the incidence of complications within 30 days was 4% and 7%, with no significant difference. However, Sun et al.  found that there were more complications in elderly patients over 75, and death was mostly due to cardiovascular and cerebrovascular diseases and non-tumor causes. Many studies support nephron-sparing surgery for elderly patients .
It should be noted that most of the previous studies were analyzed by age grouping at the age of 75 or by surgical grouping. In particular, there are few stratified studies on elderly patients aged over 75. The current study collected the data of 166 patients over 75 years old in our hospital and analyzed the general information, complications, and survival.
There was a substantial statistical difference in preoperative baseline eGFR between the two groups, which was thought to be due to age, There was also a significant difference in postoperative GFR (reexamination within 1 week following surgery) between the two groups. All patients' postoperative eGFR decreased, and as compared to the 75–79 years group, the ≥ 80 years group experienced a higher percentage drop in eGFR from baseline. Phillip et al.  and Rivero et al.  discovered that RN is related to worse renal outcomes than PN. Another study  confirmed that eGFR loss related to renal cancer surgery, whether due to PN or RN, increases the risk of chronic kidney disease but has a lesser influence on survival. In our study, there were no cases of chronic renal disease or fatalities from it in either group, which may be connected to the larger number of patients undergoing RN in this group. We believe that baseline renal function and age, which reflect general health conditions, can predict long-term renal functional results independent of surgery type. Therefore, a patient with a large tumor and chronic kidney disease may benefit from PN.
Our study found that the 75–79 years group had superior survival to the ≥ 80 years group (P < 0.0001). The results were similar to the previous studies [13, 25, 26]. This is mainly associated with older age, poor basic conditions, lower overall life expectancy, and a higher proportion of deaths from non-tumor mortality. In the ≥ 80 years group, a total of 17 patients died, 12 (70.6%) died of non-tumor causes, in the 75–79 years group, a total of 27 patients died, 12 (44.4%) died of non-tumor causes. And there was no significant difference was found in CSS between the two groups, although it was greater in the 75–79 years group, which may be related to the cause of death (P = 0.056).
Although most results suggest that OS is better with PN than with RN [27,28,29,30], similarly, most studies have shown that PN and RN have similar OS in patients, PN was not beneficial in terms of OS in elderly patients (≥ 65 years old), the 5-year OS rates after surgery were 94.7% for PN versus 91.9% for RN (P = 0.698) [13, 31]. And no significant difference was found (P = 0.281) in CSS in our study. Several previous studies have also found similar or opposite results. The Meta-Analysis (a total of 60 studies) showed that CSS estimates among all management strategies were 95 to 100% and did not differ significantly among treatments. Comparative analyses of RN and PN indicated that increasing age, larger tumor size, and higher tumor grade were the most common predictors of worse CSS . However, some studies showed no difference in CSS between RN and PN when stratified by age, tumor size or grade [33,34,35]. Further confirmation is needed from larger samples and prospective controlled studies.
Using the Clavien–Dindo classification method, postoperative complications were defined as complications occurring within 30 days after surgery . In our study, the overall complication rate was 14.45%, it was higher than that in previous studies, which may be related to the age composition of patients and the choice of surgical methods. In our study, patients aged ≥ 80 years accounted for 21.7%, and partial nephrectomy accounted for 30.7%. However, most of the previous studies focused on radical nephrectomy. The results of our study suggest that partial nephrectomy should be fully evaluated for patients ≥ 80 years of age. Although studies have shown a gradual increase in the use of partial nephrectomy in patients ≥ 65 years of age (41% in patients over 75 and 14.9% in patients over 80), the increased application rate was not significantly correlated with the presence of concomitant diseases such as heart disease (P = 0.256), kidney disease (P = 0.419), diabetes (P = 0.808), and hypertension (P = 0.931); thus patients could benefit from nephron-sparing surgery . However, that study only analyzed the application of partial nephrectomy in elderly patients in recent years and its impact on survival without summarizing the perioperative complications. Our study suggests partial nephrectomy application showed more complications in elderly patients, especially in patients aged ≥ 80 years with a lengthy hospital stay, with higher mortality. In addition, the findings of Chung et al. suggested that partial nephrectomy did not significantly prolong the survival of elderly patients .
Therefore, for patients over the age of 75, and especially for those aged ≥ 80, partial nephrectomy should be carefully selected. Further data collection is needed to verify whether partial nephrectomy is beneficial to prolong survival. However, the purpose of our study was not to reduce the use of partial nephrectomy in elderly patients but to select suitable patients based on clinical characteristics. The surgical risk prediction model can be used for preoperative risk prediction just like the Model of the American College of Surgeons to carry out precision surgical treatment . Due to the retrospective study being conducted after a considerable length of time, differences in the proficiency of surgeons and the selection of surgical methods may have resulted in biased results. The benefit of surgery in elderly patients with renal cancer remains controversial. This retrospective study aimed to explain the perioperative complications and survival of these patients, to further understand if the surgery benefits. Different from previous studies, the enrolled patients in this study were all elderly patients aged ≥ 75 years, and the conclusions were drawn after grouping analysis to further clarify the advantages and disadvantages of surgery, especially complications using the CDC system.
In conclusion, our study suggests that the overall safety of surgical treatment for elderly patients with renal cell carcinoma is satisfactory. PN should be carefully considered for patients aged ≥ 80 years, as the incidence of intraoperative and postoperative complications is relatively high. It was not to reduce the use of partial nephrectomy in elderly patients, it could be helpful in evidence-based clinical decision-making but should be critically interpreted based on an assessment of the complexity of the tumor and patient's physical condition such as age, underlying diseases and other conditions, technical feasibility, and balance between benefits and risks. Nevertheless, further research and data are needed to strengthen many aspects of the evidence base.