Cheng et al. pointed out that CA was the first method to be considered for the treatment of small kidney cancer. As Zhang et al. study showed, in treating 328 patients, the 3-year, 5-year, and 7-year CSS of patients were 97.9%, 93.5%, and 84.6%, while the failure risks of patients were 18.2% and 12.9% in the short (≤ 4) and long-term (28) effects.

The mortality rate in patients was 5.8%, with a probability of 4147 months. The study also revealed that the size could be predicted based on defined potential failure factors. No fistula was identified. According to the reported results, the great advantages of CA for the treatment of kidney tumors were oncological control, a single operative and short hospitalization period (incredible reduction of the cost of hospitalization), minor loss of creatinine clearance, and very low perforation rate. However, CA had side effects of neurovascular complications and radiated to the lungs, which was more suitable for peripheral areas and more distant areas, with tumors < 40 mm due to the low ability to destroy with heat and resistance to stent.

Large/kidneys. 3D research has shown that CA assisted by classic US also has limits in the presence of other diseases (e.g., malabsorption, high super-renal entrance, unable to cool the rectal symptoms), retroperitoneal areas with gas, intestinal handles, as though it was performed with the renal matrix. Also infiltrated and CA with microprezism and 3D research is preferable. Cryoablation is a focal treatment of kidney cancer in surgical treatment, which is to insert the cryoprobe into the tumor mass and subsequently cool the tumor mass, forming the ice ball around the tumor mass, and then gradually freeze the tumor mass tissues at -40°C for about 5-10 min.

It is an effective minimally invasive technique to destroy cancerous tissues in situ through ice ball formed by argon or helium ultra-low temperature freezing, and apply to patients with localized renal cancer who are not suitable for general surgery, high-risk surgical patients, and those who refuse to perform nephrectomy. The treatment still has the advantages of small surgery/bloodless surgery/minimal iatrogenic injury/be convenient recovery of the body function. Cryoablation is to insert a metal freezing needle (cryoneedle) into the warm area suspected of being a lesion, and then freeze the position of the cryoneedle at a temperature of -40°C for 5-10 min.

This technology is used to treat many diseases through the principle of high-energy tissue freezing. Its diagnosis and treatment are non-invasive and non-traumatic, and its effect is accurate. Its role in the field of tumor therapy has allowed the study of the mechanism of tumor cell freezing for a long time. Because only a short time is required, fast cell mutation mechanism by low-temperature freezing provides a good experimental model. According to the selection of cryodestruction time cycle, tumor cell mutation can be selected and adapted to the processing time of time series. Because most of the cryoprotective proteins are induced and affect resistance to low-temperature treatment, the temperature before the cryoprotective protein destroys gene and protein structure.

Clinical Applications Localized application of thermal energy derived from electromagnetic or acoustic sources has been employed as ablative therapy in human urological medicine since the 1970s and 1980s. The first series of studies on tumoral tissue ablation documented efficacy with volume reduction monitored by the sparing of the surrounding intervening normal renal parenchyma. Dancey and Deichert classified such thermal ablation approaches as heated through heat exchange, ultrasound, or radiofrequency energy.

In addition to heat, ultrasound generators may deliver energy, either high-frequency ultrasound or high-intensity focused ultrasound, an approach introduced as lithotripsy precisely targeting small renal masses including completely adipose renal tissue. Three main clinical applications of such renal-sparing and nerve-sparing ablative treatment have been documented: first, the application of a partial renal cell carcinoma with a synchronous renal mass in a modified anatomical approach under low-risk conditions; second, active surveillance with subsequent ablative treatment; and third, peri-operative nephron-sparing renal cell carcinoma. Although molecular analysis of small renal masses can identify a renoprotective treatment at a very early stage, clinical applications remain restricted in favor of normothermic or hypothermic surgery. The present overview discusses general principles as well as different therapeutic rationales and technical considerations for current and upcoming focal therapies.

Microwave Thermotherapy (MTT) Most studies in which MTT was evaluated as a first-line therapy for small kidney tumors (usually smaller than 4 cm) reported an excellent success rate and low major complication rate. In one paper, authors achieved slightly lower 5-year cancer-specific survival, overall survival, and metastatic-free rates as compared with the whole series of RFA-treated patients, although the difference was not statistically significant. The main advantage of MTT is that, as compared with RFA, it is not electrically conductive dependent: microwaves travel along biological tissues before being absorbed.

The main disadvantage of microwave ablation is that it can be less predictable as compared with RFA, at least from a theoretical and mathematical point of view. Of course, this potential limitation can be surpassed by using stereotactic navigation in which both the needle and the internal area around the needle are observed via real-time US or by performing an open surgery.

Microwave thermotherapy (MTT) can be offered either by means of an open surgery or by a percutaneous approach. In the first case, microwaves are delivered to the target tissue under direct ultrasound or CT guide control. In the second case, microwaves can be delivered at the tip of different types of antennas (monopolar electrode, bipolar probe, water-cooled shaft, self-expanding array, open-ended coaxial water-cooled applicator). Percutaneous MTT is normally performed in the radiology room under local anesthesia. When the procedure is complete, the radiologist performs an abdominal control scan. If tumor cells are still present, he or she delivers microwaves again.

Comparative Analysis with Other Focal Therapies The current SIT method using higher temperatures (above 70°C) and general anesthesia is more traumatic for patients compared to the RFA, performed usually using different freezing frequencies and mainly conducted under conscious sedation and/or local anesthesia. Consequently, the only SIT efficiency indicator is local organ control, and SIT is the modern standard for local kidney cancer foci treatments only when organ-preserving techniques failed.

The concept of focal therapies for kidney cancers, less aggressive compared to total nephrectomy, has more general approach problems for all focal organ-preserving techniques due to the imperfection of imaging techniques used, the absence of postoperative histological examination of the remaining portions of the organs, the insufficiency of methods or lack of methods for monitoring the processes of convalescence and recurrence. Nonetheless, a comparison of the benefits of different focal treatments in comparison with organ amputations determines the development of these techniques, actively transforms the approach in the treatment of many diseases from surgical techniques to focal ones.

High-Intensity Focused Ultrasound (HIFU) Focal therapies in uro-oncology are urgent and necessary. Is the decrease in the volume of treated parenchyma from laparoscopic radical oncological treatments? Are corporal-sparing strategies planned to play according to their rules and principles, giving primary tumors only when they respect some strategic rules as to their anatomical characteristics. Unfortunately, the strategies used are in experimental form and are only performed in high volume. It is lighted by high solutions, but it is only able to determine the feasibility purposes.

The cost of plaque is definitely perfectible, like its integration in composite strategies. On the other hand, we are at 0.5 Tesla MR guiding, limiting the applicability of the technique only for the elderly and the less obese. Its cost is also very limited. The Viagra, marketed with CE mark in Europe and FDA uses, is its clinical reference. The device consists of an extracorporeal, MRI-compatible table. The lesion is monitored with magnetic resonance imaging and can conduct a perfect tempo transfer between this monitoring and the cell killing cells, where the acoustic energy is focused. Respect to this issue, numerous studies have reported side effects. Its experience is extensive and clinically reliable. HIFU is positioned in all protocols in which there is an MR guiding, given that it is capable of guiding the location of the lesion (collaterally produces the mapping of the urethra). Several limitations must be considered with HIFU.

Advantages and Limitations Limitations Although methods such as CN, LPN, cryotreatment, radiofrequency, microwave therapy, and HIFU for the treatment of advanced kidney tumors have been developed, it is also known that these techniques are not to be considered in an antithetical way with the more traditional techniques of open, laparoscopic, or robotic renal surgery but rather, if properly integrated, are part of a multidisciplinary and multitactic therapeutic offer against kidney tumors offered to the patient.

Use of these techniques still has some intra- and post-operative limitations compared to a radical intervention, with percentage risks of local relapse and residual tumor higher for T1b (>7 cm) lesions due to their biomechanical characteristics. For these larger masses, the development and improvement of these focal treatments is in constant evolution. The availability of treatments depends on the size, location, and characteristics of the lesion. The risk of recurrence can be higher compared to resection and conservative treatment clearly cannot be the standard of care in all patients, particularly those affected by single kidney disease.

These patients, in fact, were largely excluded from recent randomized trials, and their effective benefit has never been clearly defined. No biopsy or simple pre-treatment planning exists, and often these treatments affect kidney function with the possible induction of cardiovascular diseases and related functions up to the need for dialysis. Tumor classification and prospective multi-institutional studies are indispensable to define the impact of such techniques on patient survival. In order to determine the characteristics of this term and to categorize risks more precisely, we performed this review of the current literature regarding renal tumor focal treatments.

The focal treatment option preserves kidney function and is an ideal choice for patients with a solitary kidney, bilateral renal tumors, hereditary renal cell carcinoma, multiple smaller renal tumors, contraindications to general anesthesia, and in patients who are not suitable for major surgery. As a result of using minimally invasive techniques, pain is generally reduced, hospital stay is considerably shortened, and patients are able to return to regular daily activities quickly.

The techniques used in the treatment can be applied to fragile or medically compromised patients considered not eligible for general surgical treatment, significantly reducing in-hospital permanence, hospitalization costs, and overall treatment costs for the healthcare services. The possibility of using these treatments in the active surveillance phase or in case of tumor relapse also entails the saving of the loss of productivity costs of patients involved. The reduction of the risk of spinal traction also makes this therapy an important technical option in selected fragile patients.