September 21, 2008 1 Comment
Recent interest in partial nephrectomy or nephron-sparing surgery for renal cell carcinoma has been stimulated by advances in renal imaging, improved surgical techniques, the increasing number of incidentally discovered low-stage renal cell carcinomas, and good long-term survival in patients undergoing this form of treatment. Partial nephrectomy entails complete local resection of a renal tumor while leaving the largest possible amount of normal functioning parenchyma in the involved kidney.
Evaluation of patients with renal cell carcinoma for partial nephrectomy should include preoperative testing to rule out locally extensive or metastatic disease. For most patients, preoperative renal arteriography to delineate the intrarenal vasculature aids in excising the tumor with minimal blood loss and damage to adjacent normal parenchyma. This test can be deferred in patients with small peripheral tumors. Selective renal venography is performed in patients with large or centrally located tumors to evaluate for intrarenal venous thrombosis secondary to malignancy. The latter, if present, implies a more advanced local tumor stage and also increases the technical complexity of tumor excision.
INDICATIONS FOR SURGERY
Accepted indications for partial nephrectomy in malignancies include situations in which radical nephrectomy would render the patient anephric with subsequent immediate need for dialysis.1 This encompasses patients with bilateral renal cell carcinoma or renal cell carcinoma involving a solitary functioning kidney. The latter circumstance may be present as a result of unilateral renal agenesis, prior removal of the contralateral kidney, or irreversible impairment of contralateral renal function and is seen in patients with unilateral renal cell carcinoma and a functioning opposite kidney, when the opposite kidney is affected by a condition that might threaten its future function such as calculus disease, chronic pyelonephritis, renal artery stenosis, ureteral reflux, or systemic diseases such as diabetes and nephrosclerosis.
Partial nephrectomy is also indicated in selected patients with localized benign pathology of the kidney. The indications include (a) hydronephrosis with parenchymal atrophy or atrophic pyelonephritis in a duplicated renal segment, (b) calyceal diverticulum complicated by infection or stones or both, (c) calculus disease with obstruction of the lower-pole calyx or segmental parenchymal disease with impaired drainage, (d) renovascular hypertension from segmental parenchymal damage or noncorrectable branch renal artery disease, (e) traumatic renal injury with irreversible damage to a portion of the kidney, and (f) removal of a benign renal tumor such as an angiomyolipoma or oncocytoma.
Alternatives to partial nephrectomy include simple nephrectomy and radical nephrectomy.
Figure 6-1 illustrates the normal renal arterial supply. The kidney has four constant vascular segments, which are termed apical, interior, posterior, and basilar. Each of these segments is supplied by one or more major arterial branches. Though the origin of the branches supplying these segments may vary, the anatomic positions of the segments are constant. All segmental arteries are end arteries with no collateral circulation; therefore, all branches supplying tumor-free parenchyma must be preserved to avoid devitalization of functioning renal tissue.
The normal renal venous anatomy is depicted in Fig. 6-2 (for the left kidney). The renal venous drainage system differs significantly from the arterial blood supply in that the intrarenal venous branches intercommunicate freely among the various renal segments. Ligation of a branch of the renal vein, therefore, will not result in segmental infarction of the kidney because collateral venous blood supply will provide adequate drainage. This is important clinically because it enables one to obtain surgical access safely to tumors in the renal hilus by ligating and dividing small adjacent or overlying venous branches. This allows major venous branches to be completely mobilized and freely retracted in either direction to expose the tumor with no vascular compromise of uninvolved parenchyma (Fig. 6-3).
Timing of Surgery in Bilateral Tumors
In patients with bilateral synchronous renal cell carcinoma, the kidney more amenable to a partial nephrectomy is usually approached first by the author. Then, approximately 1 month after a technically successful result has been documented, radical nephrectomy or a second partial nephrectomy is performed on the opposite kidney. Staging surgery in this fashion obviates the need for temporary dialysis if ischemic renal failure occurs following nephron-sparing excision of renal cell carcinoma.
General Operative Considerations
It is usually possible to perform partial nephrectomy for malignancy in situ by using an operative approach that optimizes exposure of the kidney and by combining meticulous surgical technique with an understanding of the renal vascular anatomy in relation to the tumor. We employ an extraperitoneal flank incision through the bed of the 11th or 12th rib for almost all of these operations; we occasionally use a thoracoabdominal incision for very large tumors involving the upper portion of the kidney. These incisions allow the surgeon to operate on the mobilized kidney almost at skin level and provide excellent exposure of the peripheral renal vessels. With an anterior subcostal transperitoneal incision, the kidney is invariably located in the depth of the wound, and the surgical exposure is simply not as good. In partial nephrectomy for benign disease, the preferred surgical approach is usually through an extraperitoneal flank incision except for cases of renal trauma, which are best approached anteriorly.
When in situ partial nephrectomy is performed for malignancy, the kidney is mobilized within Gerota’s fascia while the perirenal fat around the tumor is left intact. For small peripheral renal tumors, it may not be necessary to control the renal artery. In most cases, however, partial nephrectomy is most effectively performed after temporary renal arterial occlusion. This measure not only limits intraoperative bleeding but, by reducing renal tissue turgor, also improves access to intrarenal structures. In most cases, we believe that it is important to leave the renal vein patent throughout the operation. This measure decreases intraoperative renal ischemia and, by allowing venous back bleeding, facilitates hemostasis by enabling identification of small transected renal veins. In patients with centrally located tumors, it is helpful to occlude the renal vein temporarily to minimize intraoperative bleeding from transected major venous branches.
When the renal circulation is temporarily interrupted, in situ renal hypothermia is used to protect against postischemic renal injury. Surface cooling of the kidney with ice slush allows up to 3 hours of safe ischemia without permanent renal injury. An important caveat with this method is to keep the entire kidney covered with ice slush for 10 to 15 minutes immediately after occluding the renal artery and before commencing the partial nephrectomy. This amount of time is needed to obtain core renal cooling to a temperature (approximately 20°C) that optimizes in situ renal preservation. During excision of the tumor, invariably large portions of the kidney are no longer covered with ice slush, and, in the absence of adequate prior renal cooling, rapid rewarming and ischemic renal injury can occur. Cooling of the kidney by perfusion with a cold solution instilled via the renal artery is not recommended because of the theoretical risk of tumor dissemination. Mannitol is given intravenously 5 to 10 minutes before temporary renal arterial occlusion. Systemic or regional anticoagulation to prevent intrarenal vascular thrombosis is not necessary.
A variety of surgical techniques are available for performing partial nephrectomy in patients with malignancy. These include simple enucleation, polar segmental nephrectomy, wedge resection, transverse resection, and extracorporeal partial nephrectomy with renal autotransplantation. All of these techniques require adherence to basic principles of early vascular control, avoidance of ischemic renal damage, complete tumor excision with free margins, precise closure of the collecting system, careful hemostasis, and closure or coverage of the renal defect with adjacent fat, fascia, peritoneum, or Oxycel. Whichever technique is employed, the tumor is removed with a surrounding margin of grossly normal renal parenchyma.
Special equipment that is utilized in partial nephrectomy may include intraoperative ultrasound which is very helpful in achieving accurate tumor localization, particularly for intrarenal lesions that are not visible or palpable from the external surface of the kidney.3 The argon beam coagulator is a useful adjunct for achieving hemostasis on the transected renal surface. If possible, the renal defect created by the excision is closed as an additional hemostatic measure. A retroperitoneal drain is always left in place for at least 7 days. An intraoperative ureteral stent is placed only when major reconstruction of the intrarenal collecting system has been performed.
In patients with renal cell carcinoma, partial nephrectomy is contraindicated in the presence of lymph node metastasis because the prognosis for these patients is poor. Enlarged or suspicious-looking lymph nodes should be biopsied before the renal resection is begun. When partial nephrectomy is performed, after excision of all gross tumor, absence of malignancy in the remaining portion of the kidney should be verified intraoperatively by frozen-section examinations of biopsy specimens obtained at random from the renal margin of excision. It is unusual for such biopsies to demonstrate residual tumor, but, if so, additional renal tissue must be excised.
Segmental Polar Nephrectomy
In a patient with malignancy confined to the upper or lower pole of the kidney, partial nephrectomy can be performed by isolating and ligating the segmental apical or basilar arterial branch while allowing unimpaired perfusion to the remainder of the kidney from the main renal artery. This procedure is illustrated in Fig. 6-4 for a tumor confined to the apical vascular segment. The apical artery is dissected away from the adjacent structures, ligated, and divided. Often, a corresponding venous branch is present, which is similarly ligated and divided. An ischemic line of demarcation will then generally appear on the surface of the kidney and will outline the segment to be excised. If this area is not obvious, a few milliliters of methylene blue can be directly injected distally into the ligated apical artery to better outline the limits of the involved renal segment. An incision is then made in the renal cortex at the line of demarcation, which should be at least 1 cm away from the visible edge of the cancer. The parenchyma is divided by sharp and blunt dissection, and the polar segment is removed. In cases of malignancy, it is not possible to preserve a strip of capsule beyond the parenchymal line of resection for use in closing the renal defect.
Often a portion of the collecting system will have been removed with the cancer during a segmental polar nephrectomy. The collecting system is carefully closed with interrupted or continuous 4-0 chromic sutures to ensure a watertight repair. Small transected blood vessels on the renal surface are identified and ligated with shallow figure-of-eight 4-0 chromic sutures. The edges of the kidney are reapproximated as an additional hemostatic measure, using simple interrupted 3-0 chromic sutures inserted through the capsule and a small amount of parenchyma. Before these sutures are tied, perirenal fat or Oxycel can be inserted into the defect for inclusion in the renal closure. If the collecting system has been entered, a Penrose drain is left in the perinephric space.
When an apical or basilar partial nephrectomy is performed for benign disease, the segmental apical or basilar arterial branch is secured, and the parenchyma is divided at the ischemic line of demarcation, without the need for temporary renal arterial occlusion. More complex transverse or wedge renal resections are best performed with temporary renal arterial occlusion and ice slush surface hypothermia. The technical aspects of partial nephrectomy for benign disease are otherwise the same as those described for malignancy, with adherence to the same basic principles of appropriate vascular control, avoidance of ischemic renal damage, precise closure of the collecting system, careful hemostasis, and closure or coverage of the renal defect. In benign conditions necessitating partial nephrectomy, however, the renal capsule is excised and reflected off the diseased parenchyma for subsequent use in covering the renal defect.
Wedge resection is an appropriate technique for removing peripheral tumors on the surface of the kidney, particularly ones that are larger or not confined to either renal pole. Because these lesions often encompass more than one renal segment, and because this technique is generally associated with heavier bleeding, it is best to perform wedge resection with temporary renal arterial occlusion and surface hypothermia.
In performing a wedge resection, the tumor is removed with a 1-cm surrounding margin of grossly normal renal parenchyma (Fig. 6-5). The parenchyma is divided by a combination of sharp and blunt dissection. Invariably, the tumor extends deeply into the kidney, and the collecting system is entered. Often, prominent intrarenal vessels are identified as the parenchyma is being incised. These may be directly suture-ligated at that time, while they are most visible. After excision of the tumor, the collecting system is closed with interrupted or continuous 4-0 chromic sutures. Remaining transected blood vessels on the renal surface are secured with figure-of-eight 4-0 chromic sutures. Bleeding at this point is usually minimal, and the operative field can be kept satisfactorily clear by gentle suction during placement of hemostatic sutures.
The renal defect can be closed in one of two ways. The kidney may be closed upon itself by approximating the transected cortical margins with simple interrupted 3-0 chromic sutures, after placing a small piece of Oxycel at the base of the defect. If this is done, there must be no tension on the suture line and no significant angulation or kinking of blood vessels supplying the kidney. Alternatively, a portion of perirenal fat may simply be inserted into the base of the renal defect as a hemostatic measure and sutured to the parenchymal margins with interrupted 4-0 chromic. After closure or coverage of the renal defect, the renal artery is unclamped, and circulation to the kidney is restored. A Penrose drain is left in the perinephric space.
A transverse resection is done to remove large tumors that extensively involve the upper or lower portion of the kidney. This technique is performed using surface hypothermia after temporary occlusion of the renal artery (Fig. 6-6). Major branches of the renal artery and vein supplying the tumor-bearing portion of the kidney are identified in the renal hilus, ligated, and divided. If possible, this should be done before temporarily occluding the renal artery to minimize the overall period of renal ischemia.
After the renal artery has been occluded, the parenchyma is divided by blunt and sharp dissection, leaving a 1-cm margin of grossly normal tissue around the tumor. Transected blood vessels on the renal surface are secured as previously described, and the hilus is inspected carefully for remaining unligated segmental vessels. An internal ureteral stent may be inserted if extensive reconstruction of the collecting system is necessary. If possible, the renal defect is sutured together with one of the techniques previously described. If this suture cannot be placed without tension or without distorting the renal vessels, a piece of peritoneum or perirenal fat is sutured in place to cover the defect. Circulation to the kidney is restored, and a Penrose drain is left in the perirenal space.
Some renal cell carcinomas are surrounded by a distinct pseudocapsule of fibrous tissue. The technique of simple enucleation implies circumferential incision of the renal parenchyma around the tumor simply and rapidly at any location, often with no vascular occlusion, and with maximal preservation of normal parenchyma.
Initial reports indicated satisfactory short-term clinical results after enucleation with good patient survival and a low rate of local tumor recurrence. However, most recent studies have suggested a higher risk of leaving residual malignancy in the kidney when enucleation is performed. These latter reports include several carefully done histopathologic studies that have demonstrated frequent microscopic tumor penetration of the pseudocapsule that surrounds the neoplasm. These data indicate that it is not always possible to be assured of complete tumor encapsulation before surgery. Local recurrence of tumor in the treated kidney is a grave complication of partial nephrectomy for renal cell carcinoma, and every attempt should be made to prevent it. Therefore, it is the author’s view that a surrounding margin of normal parenchyma should be removed with the tumor whenever possible. This provides an added margin of safety against the development of local tumor recurrence and, in most cases, does not appreciably increase the technical difficulty of the operation. The technique of enucleation is currently employed only in occasional patients with von Hippel Lindau disease who have multiple low-stage encapsulated tumors involving both kidneys.
Extracorporeal Partial Nephrectomy and Autotransplantation
Extracorporeal partial nephrectomy for renal cell carcinoma with autotransplantation of the renal remnant was initially described to facilitate excision of large complex tumors involving the renal hilus. Reconstruction of kidneys with renal cell carcinoma as well as renal artery disease may also be facilitated with this approach. The advantages of an extracorporeal approach include optimum exposure, a bloodless surgical field, the ability to perform a more precise operation with maximum conservation of renal parenchyma, and a greater protection of the kidney from prolonged ischemia. Disadvantages of extracorporeal surgery include longer operative time with the need for vascular and ureteral anastomoses and an increased risk of temporary and permanent renal failure; the latter presumably reflects a more severe intraoperative ischemic insult to the kidney. Although some urologic surgeons (including the author) have found that almost all patients undergoing partial nephrectomy for renal cell carcinoma can be managed satisfactorily in situ, others have continued to recommend an extracorporeal approach for selected patients.
Extracorporeal partial nephrectomy and renal autotransplantation are generally performed through a single midline incision. The kidney is mobilized and removed outside Gerota’s fascia with ligation and division of the renal artery and vein as the last steps in the operation. Immediately after division of the renal vessels, the removed kidney is flushed with 500 ml of a chilled intracellular electrolyte solution and is submerged in a basin of ice slush saline solution to maintain hypothermia. Under these conditions, if warm renal ischemia has been minimal, the kidney can safely be preserved outside the body for as much time as is needed to perform extracorporeal partial nephrectomy.
If possible, it is best to leave the ureter attached in such cases to preserve its distal collateral vascular supply, particularly with large hilar or lower renal tumors, in which complex excision may unavoidably compromise the blood supply to the pelvis, ureter, or both. When this procedure is done, the extracorporeal operation is performed on the abdominal wall. If the ureter is left attached, it must be occluded temporarily to prevent retrograde blood flow to the kidney when it is outside the body. Often, unless the patient is thin, working on the abdominal wall with the ureter attached is cumbersome because of the tethering and restricted movement of the kidney. If these are observed, the ureter should be divided, and the kidney placed on a separate workbench. This practice will provide better exposure for the extracorporeal operation, and, as this is being done, a second surgical team can be simultaneously preparing the iliac fossa for autotransplantation. If concern exists about the adequacy of ureteral blood supply, the risk of postoperative urinary extravasation can be diminished by restoring urinary continuity through direct anastomosis of the renal pelvis to the retained distal ureter.
Extracorporeal partial nephrectomy is done with the flushed kidney preserved under surface hypothermia. The kidney is first divested of all perinephric fat to appreciate the full extent of the neoplasm (Fig. 6-7A,B). Because such tumors are usually centrally located, dissection is generally begun in the renal hilus with identification of major segmental arterial and venous branches. Vessels clearly directed toward the neoplasm are secured and divided, and those supplying uninvolved renal parenchyma are preserved. The tumor is then removed by incising the capsule and parenchyma to preserve a surrounding margin of normal renal tissue (Fig. 6-7C,D). Transected blood vessels visible on the renal surface are secured, and the collecting system is closed as described for in situ partial nephrectomy.
At this point, the renal remnant may be reflushed or placed on the pulsatile perfusion unit to facilitate identification and suture ligation of remaining potential bleeding points (Fig. 6-7E). Alternatively, the kidney can be perfused through the renal artery and vein to ensure both arterial and venous hemostasis. Because the flushing solution and perfusate lack clotting ability, there may continue to be some parenchymal oozing, which can safely be ignored. If possible, the defect created by the partial nephrectomy is closed by suturing the kidney on itself to further ensure a watertight repair (Fig. 6-7F).
Autotransplantation into the iliac fossa is done employing the same vascular technique as that in renal allotransplantation. Urinary continuity may be restored with ureteroneocystostomy or pyeloureterostomy, leaving an internal ureteral stent in place. When removal of the neoplasm has necessitated extensive hilar dissection of vessels supplying the renal pelvis, an indwelling nephrostomy tube is also left for postoperative drainage. After autotransplantation, a Penrose drain is positioned extraperitoneally in the iliac fossa away from the vascular anastomotic sites.
Partial Nephrectomy in Duplex Collecting Systems
Occasionally, heminephrectomy in a kidney with a duplicated collecting system is indicated because of hydronephrosis and parenchymal atrophy of one of the two segments. In these cases, the demarcation of the tissue to be removed is usually very evident. The atrophic parenchyma lining the dilated system can be further delineated by blue pyelotubular backflow if the ureter is ligated and the affected collecting system is distended by blue dye under pressure. In such cases, there is also often a dual arterial supply with distinct segmental branches to the upper and lower halves of the kidney. Segmental arterial and venous branches to the diseased portion of the kidney are ligated and divided. After preserving a strip of renal capsule, the parenchyma is divided at the observed line of demarcation. There is usually minimal bleeding from the renal surface, and temporary occlusion of the arterial supply to the nondiseased segment is often unnecessary. There should be no entry into the collecting system over the transected renal surface, which is then closed or covered as described above.
Patients who undergo a partial nephrectomy for renal cell carcinoma are advised to return for initial follow-up 4 to 6 weeks postoperatively. At this time, a serum creatinine measurement and intravenous pyelogram are obtained to document renal function and anatomy; in patients with impaired overall renal function, a renal ultrasound study is obtained instead of an intravenous pyelogram.
Complications of partial nephrectomy include hemorrhage, urinary fistula formation, ureteral obstruction, renal insufficiency, and infection. Significant intraoperative bleeding can occur in patients who are undergoing partial nephrectomy. The need for early control and ready access to the renal artery is emphasized. Postoperative hemorrhage may be self-limiting if confined to the retroperitoneum, or it may be associated with gross hematuria. The initial management of postoperative hemorrhage is expectant with bed rest, serial hemoglobin and hematocrit determinations, frequent monitoring of vital signs, and blood transfusions as needed. Angiography may be helpful in some patients to localize actively bleeding segmental renal arteries, which may be controlled via angioinfarction. Severe intractable hemorrhage may necessitate reexploration with early control of the renal vessels and ligation of the active bleeding points.
Postoperative urinary flank drainage after a partial nephrectomy is common and usually resolves as the collecting system closes with healing. Persistent drainage suggests the development of a urinary cutaneous fistula. This diagnosis can be confirmed by determination of the creatinine level of the drainage fluid or by intravenous injection of indigo carmine with subsequent appearance of the dye in the drainage fluid. The majority of urinary fistulas resolve spontaneously if there is no obstruction of urinary drainage from the involved renal unit. If the perirenal space is not adequately drained, a urinoma or abscess may develop. An intravenous pyelogram or retrograde pyelogram should be obtained to rule out obstruction of the involved urinary collecting system. In the event of hydronephrosis or persistent urinary leakage, an internal ureteral stent is placed. If this is not possible, a percutaneous nephrostomy may be inserted. The majority of urinary fistulas resolve spontaneously with proper conservative management, although this may take several weeks in some cases. A second operation to close the urinary fistula is rarely necessary.
Ureteral obstruction can occur after partial nephrectomy because of postoperative bleeding into the collecting system with resulting clot obstruction of the ureter and pelvis. This obstruction can lead to temporary extravasation of urine from the renal suture line. In most cases, expectant management is appropriate, and the obstruction resolves spontaneously with lysis of the clots. When urinary leakage is excessive, or in the presence of intercurrent urinary infection, placement of an internal ureteral stent can help to maintain antegrade ureteral drainage.
Varying degrees of renal insufficiency often occur postoperatively when partial nephrectomy is performed in a patient with a solitary kidney. This insufficiency is a consequence of both intraoperative renal ischemia and removal of some normal parenchyma along with the diseased portion of the kidney. Such renal insufficiency is usually mild and resolves spontaneously with proper fluid and electrolyte management. Also, in most cases, the remaining parenchyma undergoes compensatory hypertrophy that serves to further improve renal function. Severe renal insufficiency may require temporary or permanent hemodialysis, and patients should be made aware of this possibility preoperatively.
Postoperative infections are usually self-limiting if the operative site is well drained and there was no preexisting untreated urinary infection at the time of surgery. Unusual complications of partial nephrectomy include transient postoperative hypertension and aneurysm or arteriovenous fistula in the remaining portion of the parenchyma.
A recent study detailed the incidence and clinical outcome of technical or renal-related complications occurring after 259 partial nephrectomies for renal tumors at The Cleveland Clinic.2 In the overall series, local or renal-related complications occurred after 78 operations (30.1%). The incidence of complications was significantly less for operations performed after 1988 and significantly less for incidentally detected versus suspected tumors. The most common complications were urinary fistula formation and acute renal failure. A urinary fistula occurred after 45 of 259 operations (17%). Significant predisposing factors for a urinary fistula included central tumor location, tumor size >4 cm, the need for major reconstruction of the collecting system, and ex vivo surgery. Only one urinary fistula required open operative repair, and the remainder resolved either spontaneously (n=30) or with endoscopic management (n=14).
Acute renal failure occurred after 30 of 115 operations (26%) performed on a solitary kidney. Significant predisposing factors for acute renal failure were tumor size >7 cm, >50% parenchymal excision, >60 minutes ischemia time, and ex vivo surgery. Acute renal failure resolved completely in 25 patients, nine of whom (8%) required temporary dialysis; five patients (4%) required permanent dialysis.
Overall, only eight complications (3.1%) required repeat open surgery for treatment, and all other complications resolved with noninterventive or endourologic management. Surgical complications contributed to an adverse clinical outcome in only seven patients (2.9%). These data indicate that partial nephrectomy can be performed safely with preservation of renal function in most patients with renal tumors.
We recently completed a detailed analysis of tumor recurrence patterns after partial nephrectomy for sporadic localized renal cell carcinoma (RCC) in 327 patients at The Cleveland Clinic.4 The purpose of this study was to develop appropriate guidelines for long-term surveillance after partial nephrectomy for RCC. Recurrent RCC after partial nephrectomy occurred in 38 patients (1 1.6%) including 13 patients (4.0%) who developed local tumor recurrence (LTR) and 25 patients (7.6%) who developed metastatic disease (MD). The incidence of postoperative LTR and MD according to initial pathologic tumor stage was as follows: 0% and 4.4% for T1 RCC, 2.0% and 5.3% for T2 RCC, 8.2% and 11.5% for T3a RCC, and 10.6% and 14.9% for T3b RCC. The peak postoperative intervals for developing LTR were 6 to 24 months (in T3 RCC patients) and >48 months (in T2 RCC patients).
The above data indicate that surveillance for recurrent malignancy after partial nephrectomy for RCC can be tailored according to the initial pathologic tumor stage. The recommended surveillance scheme is depicted in Table 6-1. All patients should be evaluated with a medical history, physical examination, and selected blood studies on a yearly basis. The latter should include serum calcium, alkaline phosphatase, liver function tests, blood urea nitrogen, serum creatinine, and electrolytes. A 24-hour urinary protein measurement should also be obtained in patients with a solitary remnant kidney to screen for hyperfiltration nephropathy.9 Patients who have proteinuria may be treated with a low-protein diet and a converting enzyme inhibitor, which appears to be beneficial in preventing glomerulopathy caused by reduced renal mass.
The need for postoperative radiographic surveillance studies varies according to the initial pT stage. Patients who undergo partial nephrectomy for pT1 RCC do not require radiographic imaging postoperatively in view of the very low risk of recurrent malignancy. A yearly chest x-ray is recommended after partial nephrectomy for pT2 or pT3 RCC because the lung is the most common site of postoperative metastasis in both groups. Abdominal or retroperitoneal tumor recurrence is uncommon in pT2 patients, particularly early after partial nephrectomy, and these patients require only occasional follow-up abdominal CT scanning; we recommend that this be done every 2 years in this category. Patients with pT3 RCC have a higher risk of developing LTR, particularly during the first 2 years after partial nephrectomy, and they may benefit from more frequent follow-up abdominal CT scanning initially; we recommend that this be done every 6 months for 2 years and every 2 years thereafter.
The technical success rate with partial nephrectomy for renal cell carcinoma is excellent, and several large studies have reported 5-year cancer-specific survival rates of 87% to 90% in such patients (Table 6-2). These survival rates are comparable to those obtained after radical nephrectomy, particularly for low-stage renal cell carcinoma. The major disadvantage of partial nephrectomy for renal cell carcinoma is the risk of postoperative local tumor recurrence in the operated kidney, which has been observed in 4% to 6% of patients. These local recurrences are most likely a manifestation of undetected microscopic multifocal renal cell carcinoma in the renal remnant. The risk of local tumor recurrence after radical nephrectomy has not been studied, but it is presumably very low.
Recent studies have clarified the role of partial nephrectomy in patients with localized unilateral renal cell carcinoma and a normal contralateral kidney. The data indicate that radical nephrectomy and partial nephrectomy provide equally effective curative treatment for such patients who present with a single, small (<4 cm), and clearly localized renal cell carcinoma.1,5 The results of partial nephrectomy are less satisfactory in patients with larger (>4 cm) or multiple localized renal cell carcinomas, and radical nephrectomy remains the treatment of choice in such cases when the opposite kidney is normal. The long-term renal functional advantage of partial nephrectomy with a normal opposite kidney requires further study.