N S S (Nephron-Sparing Surgery) The traditional surgical procedure for the treatment of kidney cancer is radical nephrectomy, which requires the removal of the entire kidney as well as the perirenal fatty tissue and adrenal glands, and has been considered the standard procedure for the treatment of kidney cancer for many years. Nephrone-Sparing Surgery (NSS) is a procedure that involves the removal of the entire kidney as well as the perinephric fatty tissue and adrenal glands.
Surgery (NSS) is a revolutionary advancement in renal surgery and has been gaining attention in the treatment of kidney cancer in recent years. With the improvement of medical imaging technology, the improvement of surgical concept and technology, the new understanding of biological characteristics of kidney cancer and the increase of early detection cases, the clinical application of NSS has gradually increased. Traditional radical nephrectomy has its inherent limitations. First, there is a risk of bilateral development of kidney cancer, which has a 4% chance of occurring. If nephrectomy has been performed for kidney cancer and the opposite kidney also develops kidney cancer, it will be very difficult to treat the kidney cancer, and if nephrectomy is performed again, the patient will be dependent on dialysis for life. Secondly, many very common diseases, such as hypertension and diabetes, have potential harm to kidney function, which will undoubtedly increase the risk of kidney failure after nephrectomy. Moreover, clinically, we often encounter some very small kidney tumors (less than 2cm or even 1cm), for these small tumors, it is difficult to determine the benignity and malignancy by imaging, therefore, there is a dilemma in treatment: if we choose to observe, the malignant tumors may cause delay and progress; if we perform nephrectomy, the postoperative pathology confirms that the tumor is benign, from a certain point of view, it is a kind of overtreatment, which is difficult for patients to Acceptance. NSS includes partial nephrectomy (Partial
Nephrectomy (PN), wedge nephrectomy and tumor excision, the biggest advantage of NSS is that it can preserve as many functional kidney units as possible to protect kidney function, NSS was initially used to treat benign kidney diseases, and only recently it has been used to treat kidney cancer, many clinicians worry that NSS treatment for kidney cancer will lead to higher recurrence rate and shorter survival. However, many clinical studies have confirmed that for early stage limited renal cancer, the survival rate after NSS is comparable to radical nephrectomy, with a 5-year cancer-specific survival rate of 88%-98%. Moreover, several recent publications have reported that the overall survival rate of kidney cancer patients who underwent NSS was better than those who underwent radical nephrectomy, due to the significantly reduced chance of cardiovascular disease and renal impairment after NSS compared with nephrectomy. So, what kind of kidney cancer is suitable for NSS? The indications for NSS are divided into absolute indications, relative indications and elective indications. Bilateral kidney cancer, isolated kidney cancer (including those after contralateral nephrectomy and congenital) is the absolute indication for NSS. One-sided kidney cancer with contralateral renal dysplasia or disorders potentially affecting renal function such as chronic glomerulonephritis, diabetes mellitus, hypertension, etc. are relative indications. There is no specific limitation on tumor size for NSS indications and relative indications. The hot topic of current research is how to limit the size of tumor for selective indications. The traditional view is that the selective indication for NSS is renal tumors ≤4 cm in diameter (stage T1a), and this view is widely accepted. However, many recent reports have shown that NSS is an equally effective and acceptable surgical approach in tumors 4-7 cm in diameter. With this in mind, the European Association of Urology (EAU) has published a series of reports on NSS.
Associationof Urology (EAU) guidelines for the diagnosis and treatment of renal cell carcinoma also state that NSS can be performed electively for renal carcinoma with a diameter of 4 to 7 cm (stage T1b).
According to our clinical experience, tumor size is not the only criterion for elective indication, but the location of the tumor is very important, and “easy to resect” is an important reference criterion. If the tumor is located in the upper or lower pole, with convex growth and easy to resect, even if it is larger than 4 cm, NSS can be performed electively. envelope, but there is often a pseudo-envelope composed of compressed renal parenchyma and fibrous tissue. Usually, surgeons use the pseudo-envelope as a marker to determine the extent of surgical resection. Traditionally, the surgical margin for NSS is 10 mm or more of renal parenchyma outside the pseudoperitoneum. 10 mm is a safe margin, but it may also result in the loss of many functional renal units, and there is a great deal of controversy regarding the extent of the margin. In recent years, many studies have shown that a 5-mm surgical margin can achieve the same treatment results without increasing the recurrence rate, and some scholars even believe that extraperitoneal resection (i.e., a 0-mm margin) is safe enough. In response to this hot issue, our urological oncology department has conducted a special scientific study, and the preliminary conclusion is that, in general, a 4-mm margin should be available to ensure safe tumor removal. In addition to tumor size and location, the extent of tumor cutting margin should be combined with the degree of pseudo-envelope integrity, CT and other imaging examinations to estimate malignancy and other factors to determine and select an individualized cutting margin range. It is generally believed that NSS has more complications than radical nephrectomy. The main ones are bleeding, urinary leakage, and acute renal function decay. Nevertheless, with the advancement of surgical techniques and the update of instruments and hemostatic materials, NSS has become a relatively safe procedure.