The development and availability of modern imaging techniques has led to the detection of more small renal masses (SRMs) each year, making the diagnosis and treatment of SRMs a growing urological concern. Similar to other solid occupying lesions of the kidney, renal cell carcinoma (RCC) still accounts for the majority of SRMs (80-90%), while other benign lesions (vascular smooth muscle lipoma, inflammation, etc.) account for only 10-20%. rCC-SRMs are also known as small renal carcinoma and limited renal carcinoma. The choice of their treatment has been a hot topic of clinical research and debate. This article outlines the main tools and efficacy assessment regarding the treatment of SRMs in recent years, focusing on RCC-SRMs. The definition of small renal carcinoma is not yet unified, and in this paper, for the purpose of treatment classification, it is defined as an early stage tumor with a maximum diameter of Q4 cm, confined to the kidney, corresponding to a tumor before TNM stage T1a, also known as limited renal cancer. Radical nephrectomy (RN) technically requires removal of the affected kidney, its perinephric fascia and fat capsule, and has long been considered the gold standard of surgical treatment for RCC. Since RN requires the removal of one functional kidney, there is a potential threat in terms of long-term renal function protection. At the beginning of this century, Lau WK et al. showed that patients undergoing RN had a significantly greater risk of chronic kidney disease within 10 years after surgery than control patients (of equal age and stage) undergoing partial nephrectomy (PN), even if the contralateral kidney was completely normal, while postoperative complications, cancer-free survival, and distant metastases were not significant. There was no significant difference in postoperative complications, cancer-free survival, distant metastases and other tumor treatment-related indicators. A similar study by McKiernan et al. subsequently confirmed this and indicated that patients after RN were more likely to develop renal insufficiency even after excluding the effects of hypertension and diabetes mellitus. In addition, tumor metastasis in the contralateral kidney after RN is also a worrying factor. This suggests that resection of the entire kidney may not be necessary or even risky for patients with limited renal cancer who can be technically suitable for partial nephrectomy. For limited renal cancer, there is more consensus that RN is available for patients with large (>7 cm), centrally located or multiple cancers. Since the 21st century, laparoscopic techniques have developed rapidly in the field of urology, and laparoscopic radical nephrectomy (LRN) — transabdominal or retroperitoneal — has now been standardized and has become a more mature procedure. The efficacy and complication rates are basically comparable to those of open RN, and its minimally invasive advantages are more prominent for small renal cancers. For a specific patient, the approach used depends on the equipment of the medical unit and the personal experience of the surgeon. The earliest form of NSS is partial nephrectomy (PN), which was first reported by Simon in 1876 and standardized by Puigvert et al. in 1976, and has been followed by various forms of NSS, all of which have in common the aim of removing the lesion while preserving as much functional kidney tissue as possible in order to minimizing the loss of total renal function. The technical requirement for PN is complete removal of the tumor and sufficient normal renal tissue margins to ensure tumor-negative preservation of the margins. PN has long been the best surgical option for small, benign lesions in isolated (anatomic or functional) kidney cancer. This concept has gradually changed in the last 20 years. On the one hand, the long-term protection of total renal function has become a focus of attention due to the large number of small renal cancers detected and their improved treatment outcomes, and there is a greater awareness of the potential risk of renal function that may be caused by RN; on the other hand, the maturation of PN technology and the large number of cases accumulated have made it possible to strictly pairwise compare the oncologic outcomes of PN and RN. The more consistent view is that PN is significantly worse for small renal cancer (7 cm) with the above indices. There are no further studies to support Matthieu’s view, but it has been suggested that for larger tumors, in addition to considering the size of the tumor, a combination of other factors such as tumor growth pattern, location, and Fuhrman classification may be more accurate in predicting the long-term outcome of PN. In some medical units where laparoscopic techniques are more maturely performed, laparoscopic partial nephrectomy (LPN) has become a treatment for small renal tumors (4 cm) has also been reported individually, and the perioperative comparison with OPN and the intermediate and long-term outcomes need to be further evaluated. Renal tumor enucleation does not require complete removal of the tumor envelope (or pseudo-envelope), but only enucleation of the tumor from the capsule wall as a whole. Although it has also been shown that successful renal tumor enucleation does not improve the positive rate of cut margins, in view of the long-term outcome of oncologic treatment, this technique is no longer recommended for malignant SRMs and is limited to the treatment of benign tumors where the diagnosis has been largely established, given the maturity of OPN and LPN dates. Since Uchida et al. first reported the treatment of SRMs by cryosurgery (CS) in 1995, several similar methods have emerged so far, such as radiofrequency ablation (RF), microwave thermotherapy (MW), and The common point of these methods is that they can cause local necrosis, detachment or vaporization of tumor cells through cold or heat, and achieve the effect of local tumor removal with slight damage to surrounding normal tissues. All of the above methods can be implemented through minimally invasive methods such as percutaneous puncture and laparoscopy. The advantages of these methods are simple operation, short operation time, less bleeding, less surgical trauma, and easy to be tolerated by patients; the disadvantages of these methods are that they require special equipment, may be more expensive, difficult to obtain fresh tissue for pathological diagnosis, and slightly higher local recurrence rate than LPN in the middle and long term. While watchful waiting (WW) was previously used for benign SRMs, recent studies have shown that WW is also an optional method for some patients with malignant SRMs.A recent meta-analysis by Chawla et al [22] showed that most SRMs grew slowly naturally (0.09-0.86 cm/year, mean 0.28 cm/year), and a small proportion (26-33%) SRMs were quiescent during the initial 29 months of follow-up (on average), while only a very small percentage (1%) of masses developed distant metastases during the follow-up period. The biggest drawback of this study is the lack of pathological diagnosis, which makes it difficult to classify and compare the masses in relation to their pathological type and malignancy, so WW for highly suspected malignant SRMs is currently only applicable to a small number of patients of advanced age who have difficulty tolerating any invasive treatment. Radical total renal ureterotomy + bladder sleeve set excision has long been the gold standard for the treatment of renal pelvic cancer, and endoscopic (ureteroscopic or percutaneous nephrological) treatment of renal pelvic cancer is limited to a few special cases, such as isolated kidneys (anatomic or functional), bilateral renal pelvic cancer, and those with other serious disorders that are difficult to tolerate larger surgery. In recent years, with the development and maturation of endoscopic techniques, attempts have been made to treat small renal pelvis cancers with normal contralateral kidneys, so that total renal function can be protected to the greatest extent.