December 22, 2008 Leave a comment
Malignant tumors of the upper urinary tract are uncommon and account for only 5% to 10% of all urothelial malignancies. The peak incidence is in the sixth and seventh decade of life with a male predominance of 2:1.3 Most upper tract tumors are transitional-cell carcinoma (TCC, 85% to 90%), with 10% to 15% squamous cell carcinoma or mixed TCC and squamous. Adenocarcinoma of the renal pelvis is extremely rare, accounting for only 1% of upper tract tumors.
Cigarette smoking is the major risk factor for development of TCC of the renal pelvis. It has been reported that there is a three- to sevenfold increased risk of carcinoma associated with cigarette smoking and that cessation of smoking is associated with a decreased risk.
Phenacetin abuse is also associated with an increased risk of TCC of the renal pelvis. Although the specific mechanism of tumorigenesis is unknown, the phenacetin metabolite 4-acetoaminoprophenol is thought to cause chronic inflammation and papillary necrosis. The combination of papillary necrosis and chronic inflammation has been associated with a 20-fold increased risk of cancer development.
Balkan nephropathy, also known as Danuvian endemic familial nephropathy, is a condition strictly associated with TCC of the upper tracts. This endemic disease is confined to the Balkan states that lie on the Danube river. Cancer of the renal pelvis in these states accounts for 42% of renal tumors. The specific cause is unknown, although the drinking water has been suggested. The tumors are typically low grade, multifocal, and slow growing. Bilateral tumors occur 10% of the time. Occupational risk factors have also been correlated with TCC of the renal pelvis, including exposure to chemicals in the rubber, petroleum, plastics, and aniline dye industries. Forty to eighty percent of patients with upper tract tumors will have urothelial carcinomas at some time elsewhere in the urinary tract, usually in the bladder. About 3% of patients with transitional cell cancer of the bladder develop upper tract tumors; however, patients with urothelial tract tumors of the prostate or urethra have approximately a 30% risk of developing upper tract tumors.
Approximately 80% of patients present with hematuria. Some patients present with flank pain or constitutional symptoms. Intravenous pyelography (IVP) is the initial study of choice in the evaluation of a patient suspected of having a renal pelvic or ureteral tumor. Assessment of the entire urinary tract is important in evaluating patients diagnosed with a renal pelvic or ureteral tumor because the upper urinary tract has a high potential of developing multiple tumors as described by the field-change theory. Grabstald reported that approximately 50% of patients with renal tumors have coexisting tumors in the ipsilateral ureter and bladder, and 3% to 4% of those patients have tumors in the contralateral upper urinary system. A retrograde pyelogram is usually indicated if the collecting system of the affected kidney is not completely visualized or in the case of renal insufficiency or contrast allergy. Additional urothelial assessment may include renal pelvic and/or ureteral washing for cytology, brush biopsies, cystoscopy, and bladder washing for urinary cytology. The role of ureteroscopy in the diagnosis of upper tract tumors is complementary and may confirm the findings of the IVP, retrograde pyelography, and cytology. Ureteroscopy may aid in visual identification and biopsy of tumors for grading and staging. Additional staging evaluation for the detection of metastatic disease should include a chest radiograph and/or computed tomography (CT) of the chest, abdomen, and pelvis. A bone scan may be obtained in patients with an elevated serum calcium, alkaline phosphatase, or bony abnormalities seen on CT scan.
INDICATIONS FOR SURGERY
Nephroureterectomy with excision of a cuff of bladder is the classic surgical procedure for carcinoma of the renal pelvis or ureter. However, conservative surgery may be indicated in those patients diagnosed with a small, solitary, well-differentiated papillary tumor. Current staging techniques, however, may make accurate preoperative staging and grading of tumors difficult. In addition, half of all cases of ureteral tumors involve at least the musculature. Furthermore, there is a high incidence of multiple ipsilateral tumors. Last, recurrent tumors in the remaining ureteral stump have been reported in more than 30% of patients treated by nephrectomy and partial ureterectomy. Although patients with solitary distal ureteral tumors may be successfully treated with distal ureterectomy and ureteroneocystostomy, in general, a conservative surgical approach should be reserved for the highly selected patient pop-ulation in whom nephron sparing is essential, i.e., pa-tients diagnosed with bilateral tumors, Balkan nephropathy, patients with a solitary kidney, renal insufficiency, and patients with comorbid health problems. Patients treated with a conservative approach are at increased risk of local recurrence and require frequent and careful follow-up including IVPs, retrograde pyelograms, and endoscopies.
Alternatives to nephroureterectomy include (a) endoscopic resection and/or fulguration, in either a retrograde or antegrade fashion, (b) topical chemo- or immunotherapy via either a nephrostomy tube or ureteral stent, (c) external beam radiotherapy, or (d) laparoscopic nephroureterectomy.
Lesions in the ureter may be treated with resection of the ureteral tumor and ureteroureterostomy, replacement with ileal interposition, and ureteral reimplantation. These operations require a careful assessment of the entire urothelium and careful follow-up. Because of the “field change” effect of the urothelium and multiplicity of tumors, these operations may not be appropriate in patients with high-grade or -stage tumors.
In performing a nephroureterectomy, technical considerations include the choice of incision, whether it is appropriate and to what extent the surgeon should perform a lymph node dissection, and excision of bladder cuff and distal ureter via an intravesical versus extravesical approach.
An intrathoracic, extrapleural, extraperitoneal approach, removing the kidney within Gerota’s fascia without removing the adrenal gland, is our preferred procedure. In order to gain proper exposure, the incision can never be too high, and thus, a tenth interspace or supra-11th-rib incision is generally utilized. The patient is placed in a modified flank position (approximately 60 degrees rotated) with the table flexed and the kidney rest elevated. The patient is taped into position with wide adhesive tape, and an arm rest is utilized. The patient is adequately padded with an axillary roll, pillows, and sheets and is prepped and draped from nipples to the symphysis pubis in the usual sterile fashion.
The 11th rib and the tenth intercostal space are identified, and a supra-11th-rib incision is made in the tenth intercostal space. The incision extends from the edge of the erector spinae muscle and courses obliquely and medially to the lateral border of the rectus fascia to incise the external and internal oblique muscles, exposing the transversalis fascia, and the latissimus dorsi and serratus muscles, exposing the intercostal muscles. The lumbodorsal fascia is then incised at the level of the tip of the 11th rib to avoid inadvertent division of the peritoneum or pleura.
The peritoneum is mobilized off the posterior aspect of the transversalis muscle, moving the peritoneum medially and inferiorly. Primarily by use of blunt dissection with minimal sharp dissection, Gerota’s fascia is mobilized superiorly from the diaphragm and posteriorly and inferiorly from the psoas and quadratus musculature. The intercostal muscles are then incised, carefully avoiding the pleural membrane. The plane between the pleura and chest wall is identified with careful blunt dissection along the tenth rib using a Kitner dissector. The diaphragmatic attachments to the 11th and 12th rib are transected sharply down to their insertion between the quadratus and psoas muscles, avoiding the intercostal nerve and vessels. Sharp dissection is continued posteriorly until the intercostal ligament is divided, allowing the rib to hinge posteriorly.
A self-retaining retractor is placed into the wound for optimal exposure. A Balfour or Finochietto retractor may be used, but a multibladed ring retractor that is secured to the operating table such as a Buckwalter retractor is preferable. The renal mass within Gerota’s fascia is rotated medially, and the dissection is carried posteriorly off the psoas and quadratus musculature. The iliohypogastric and ilioinguinal nerves and 12th thoracic neurovascular bundle can usually be identified .
The colon is then held medially and superiorly, an avascular plane between the colonic mesocolon and Gerota’s fascia is developed, and the renal mass is sharply separated from the peritoneum. By use of sharp and blunt dissection, the superior and inferior aspects of the kidney are dissected free of the adrenal gland and surrounding tissues, respectively. There may be several vessels between the adrenal gland and the kidney that should be ligated with ligaclips. The kidney is dissected posteriorly to the level of the renal hilum. Attention is directed to the main renal vessels. The pulsating renal artery is identified by palpation, double ligated as it exits the aorta with 0 silk sutures and then divided.
On the right side, especially with a large tumor mass, the artery may be approached anteriorly or in the interaortocaval region, though the preferred approach to the right renal artery is posteriorly. On the left side, the gonadal and adrenal veins are identified anteriorly, as is the renal vein. The gonadal and any lumbar veins are ligated before double ligating the renal vein with 2-0 silk suture. On the right side, the inferior vena cava is identified as well as the renal vein. Careful palpation for a second renal artery is important before ligation of the renal vein. The remaining soft tissue attachments to the kidney should be divided so that the only remaining attachment is to the ureter.
Attention is then directed to the inferior aspect of the kidney. The ureter is identified and dissected free to a level distal to the bifurcation of the iliac vessels. The ureter is ligated distally with a 0 silk suture, making sure not to include any surrounding tissue in the ligature. A large straight clip is placed proximally to prevent urine spillage, and the ureter is divided. The specimen is then removed.
Transitional-cell carcinoma may spread by direct extension or metastasis by hematogenous or lymphatic routes. Therefore, a regional lymphadenectomy should be performed as part of the surgical procedure. A lymph node dissection is performed by identifying the midline of the aorta for a left-sided tumor, and the vena cava for a right-sided tumor. Starting from just cephalad to the renal hilum to the level of the inferior mesenteric artery, the lymphatic tissue is dissected using a “split and roll technique” with ligaclips placed on the lymphatics to avoid a lymphocele.
Hemostasis is obtained using electrocautery. The diaphragm is not repaired if only the lateral attachments have been taken down. If a pleurotomy has been made, a red rubber catheter with additional side holes cut out is placed into the pleural space, and the pleurotomy is closed with a running 3-0 chromic suture. The kidney rest is lowered, the table is taken out of flexion, and the wound is closed in two layers using a continuous suture of #1 PDS. The skin is closed using staples. The pleural cavity is then bubbled out with the red rubber catheter in a basin of saline. When fluid and bubbles cease to emerge from the catheter, it is removed, and additional skin staples are applied. Auscultation of the chest at the apex of the lung as well as a chest x-ray should be performed postoperatively to diagnose a pneumothorax. If there are any concerns, a temporary chest tube may be placed.
The patient is taken out of flank position, placed in supine position over the break of the operating room table with the table flexed, and prepped and draped in the usual sterile fashion. A 20-Fr Foley catheter is passed into the bladder, and the bladder is then filled with 200 to 300 cc of normal saline. A lower midline abdominal incision is made and carried down through the rectus and transversalis fascia. A Balfour retractor is placed. The bladder is identified and opened longitudinally between two laterally placed 2-0 Vicryl stay sutures. Additional stay sutures are placed at the apex of the incision in the bladder. The ureteral orifices are identified, the bladder is packed with several sponges, and the bladder blade is placed in the dome of the bladder. A 5-Fr feeding tube is placed in the ipsilateral ureteral orifice and sewn in place with a 4-0 chromic suture. The ureteral orifice is circumscribed sharply, including a 1-cm cuff of bladder. The ureter is dissected from its orifice using a pinpoint electrocautery and sharp dissecting scissors .
The entire distal ureter is dissected free to the level of the 0 silk tie, removed with a cuff of bladder, and passed off the table as a specimen. In most cases the remaining stump of distal ureter may be removed entirely with an intravesical approach; however, in some cases additional extravesical dissection is required in which the superior and middle vesicle pedicles are divided. A two-layer closure of the posterior bladder wall is performed using 2-0 Vicryl suture to close the muscle and serosa and 5-0 chromic to close the bladder mucosa. A 3-0 Vicryl continuous suture and subsequently 2-0 Vicryl figure-of-eight Lembert sutures are used to close the bladder incision in two layers. A Davol drain is placed in the pelvis and secured with a 3-0 nylon suture. The abdomen is closed with a continuous #1 PDS suture. The skin is closed with staples.
Early complications include hemorrhage, wound infection, pneumothorax, atelectasis, and pneumonia. Meticulous dissection around the renal vessels, aorta, and vena cava will aid in decreasing intraoperative blood loss. The supra-11th-rib incision provides excellent exposure to the great vessels and kidney, thus reducing the chance of inadvertent injury to the vasculature. Later complications include “flank sag,” which may be related to division of more than one intercostal nerve.
The survival rate after nephroureterectomy is dependent on the stage and grade of the tumor. Superficial low-grade tumors rarely metastasize and when adequately treated rarely decrease life expectancy. Invasive lesions have a higher metastatic rate and are associated with a poorer prognosis. Patients with low-grade and high-grade tumors have approximately 80% and 20% survival at 5 years, respectively.4 Patients with pT2–3a renal pelvic and ureteral tumors have a 75% and 15% survival at 5 years, respectively, and patients with pT3b–4, N+ tumors have approximately a 5% survival at 5 years. Interestingly, in patients with ureteral tumors, survival may be more dependent on the stage and grade of tumor than the surgical approach.