Randomized, open-label clinical trial to compare renal volumetry pre and post operative in patients undergoing two types of partial nephrectomy techniques for renal tumors: robot-assisted vs videolaparoscopic.

Renal tumors are an important public health issue, representing approximately 4,2% of all newly diagnosed cancers around the world. Renal tumors are more prevalent in adults over 45 years old, and with higher frequency in men than women. Many risks factor have already been identified, including smoking (increase in twice the renal cancer risk), obesity, hypertension, and renal cancer familiar history.

Surgery is one of the main treatment options for renal tumors and is considered the only curative treatment for localized ones. The most common surgeries used to treat it are Partial Nephrectomy (PN) and Radical Nephrectomy (RN). PN in indicated for smaller tumors (smaller than 4cm size) once it has already demonstrated renal function preservation and decrease chronic kidney disease (CDK) risk and cardiovascular events. Furthermore, RN is indicated for bigger tumors or for those who are centrally located in the middle of the kidney.

In the last years, PN use have been increased and consequently, RN use has been decreased.

According to a recent published study, PN use for T1a tumors increased from 20,2% in 2004, to 59,7% in 2015. Furthermore, 5-year cancer survival rates between patients undergone PN or RN was similar, with PN being more associated with lower general mortality rates. However, PN is technically more challenging and is associated with complications and local higher recurrence risks.

Both are viable surgery options for renal tumors and the chosen technique of them should be considered according to surgeon expertise, patient's comorbidities, and tumor characteristics.

There are some PN ways, including Open (OPN), Laparoscopic (LPN) and robot-assisted (RAPN), however the best technique is still unknown. Some studies have been comparing this three, and a recent 39-studies metanalysis evaluating 11.310 patients reported RAPN is which presented lower general complications, less warm ischemia period, and higher kidney function preservation rates in comparison with LPN or OPN. Other 29-studies metanalysis evaluating 5952 patients showed RAPN presented lower surgical and hospitalization periods compared to OPN and LPN. However, RANP is associated with higher costs and a longer learning curve than other NP techniques.

Renal volumetry is an important measure for kidney function evaluation which aids on surgical approach choose for NP. In the present, there are some ways to evaluate pre and post operative kidney volumetry such as TC, RMN, and 3D ultrasonography (3DUS). A systematic review and metanalysis of 26 studies analyzed 1918 patients, and showed TC preoperative renal volumetry is the best way to predict postoperative kidney function and the need for a NP. Renal volumetry by TC and RMN postoperative also were considered good trustful measures to evaluate volumetry and remained kidney functions after PN. 3DUS appear to be a more economic and good measure to evaluate it with a good precision compared to what was found to TC and RMN.

In general, pre and postoperative renal volumetry are an important measure to guide surgeons on the best surgery approach in PN, and right renal volumetry image evaluation should be considered according to costs available, patients characteristics and surgeon experience. Then, this study aims to compare NP techniques (VPN and RAPN) using renal volumetry pre and postoperative.

Inclusion Criteria:

• Patients between 18 and 99 years old;
• Patients with non-metastatic renal cancer (confirmed by pre operatory TC);
• Patients eligible for videolaparoscopic partial nephrectomy;
• Patients who signed study informed consent form

Exclusion Criteria:

• Pregnant patients;
• Patients with concomitant indications with nephrectomy;
• Patients with a clinical condition that contraindicates nephrectomy;
• Patients with a clinical condition that contraindicates robot-assisted surgeries (determined by urology team);
• Patients with previous surgeries that contraindicates robot-assisted surgeries (determined by urology team);