PERSPECTIVE, PATTERNS OF SPREAD, AND PATHOLOGY
Multifocality is a significant attribute of cancers of the renal pelvis and ureter.
PERSPECTIVE AND PATTERNS OF SPREAD
Multifocality is a significant attribute of cancers of the renal pelvis and ureter. Once a cancer appears and progresses, the issue of seeding versus field cancerization is a concern. The probability of an associated bladder cancer reaches 75% if both the renal pelvis and ureter have lesions versus half that with single cancers. Smokers and analgesic abusers (phenacetin) are at risk. Gross hematuria is the presenting sign in most patients (75%–90%), with the associated triad of flank mass, pain, and hematuria occurring in fewer than one fifth (20%) of patients. The diagnosis is readily made with either intravenous or retrograde urography, and the absence of the usual abundant tumor neovascularization suggests renal pelvic cancer. The issue of multifocal disease is addressed on surgical resection—that is, nephrectomy with total ureterectomy including a cuff of the urinary bladder. Isolated ureteral cancers are rare (1%) and predominate in males (2:1).
Figure 36.1| Urothelial tumors of the renal pelvis are similar to bladder. A. Low-grade papillary urothelial carcinoma consists of exophytic papillae that have a central connective tissue core and are lined by slightly disorganized transitional epithelium. B. Low-grade papillary urothelial carcinoma at higher magnification shows mild architectural and cytologic atypia. C. High-grade papillary urothelial carcinoma shows prominent architectural disorganization of the epithelium which contains cells with pleomorphic hyperchromatic nuclei. D. Invasive high-grade papillary urothelial carcinoma consists of irregular nests of hyperchromatic cells invading into the muscularis.
Figure 36.2 | A. Coronal. B. Traverse. Patterns of spread (cancer crab) of renal pelvis and ureter cancer color coded for stage: Tis or Ta, yellow; T1, green; T2, blue; T3, purple; and T4, red. The concept of visualizing patterns of spread to appreciate the surrounding anatomy is well demonstrated by the six-directional pattern (SIMLAP, Table 36.2).
The renal pelvises are akin to a hollow structure with a thin wall. The pattern of spread is into the muscle wall and then through the wall into the peripelvic fat and periureteral junction. As it advances, the renal parenchyma may be invaded. Seeding into the ureters and bladder is quite common (Fig. 36.2; Table 36.2).
PATHOLOGY
The majority of cancers are transitional cell (90%); the rest are squamous cell cancers often associated with chronic inflammation or infection of the renal pelvis. Adenocarcinomas are extremely rare. As it advances, the renal parenchyma may be invaded. Seeding into the ureters and bladder are quite common (Fig. 36.1; Table 36.1).
TNM STAGING CRITERIA
TNM STAGING CRITERIA
Cancers of the renal pelvis and ureters were distinguished in the fourth edition of the AJCC Cancer Staging Manual and have followed the tradition of staging hollow organs, similar to the digestive system (Fig. 36.3), that is, based on the depth of renal pelvis wall invasion rather than size.
Stage T1 cancer invades into subepithelial connective tissue and stage T2 cancer into the muscular layer. Stage T3 cancer invades into perirenal fat through the renal pelvis wall, and T4 cancer invades into adjacent organs (Fig. 36.3).
The regional nodes are the same for renal cancers and renal pelvis cancers. However, their definitions are different in the fourth edition of the AJCC Cancer Staging Manual. In renal cancers, the major criterion is node number: N1 is single and N2 is multiple nodes. In contrast, in renal pelvis cancers, size of the nodes is the critical criterion: N1, ≤2 cm; N2, 2 to 5 cm; and N3, 5 cm. Although lymph node stages defined in the fourth edition were the same, they have diverged as noted for renal parenchymal versus renal pelvis cancers.
SUMMARY OF CHANGES SEVENTH EDITION AJCC
• The definitions of TNM and the Stage Grouping for this chapter have not changed from the Sixth Edition (Fig. 26.3).
• Grading: A low- and high-grade designation will replace previous four-grade system to match current World Health Organization/International Society of Urologic Pathology (WHO/ISUP) recommended grading system.
The TNM Staging Matrix allows for identification of Stage Group once T and N stages are determined (Table 36.3). T stage determines stage group.
RENAL PELVIS
Figure 36.3 | TNM renal pelvis and ureter cancer diagram. Renal pelvis cancers and ureteral cancers are often detected early and resectable when confined (stages I, II) or with minimal penetrations of their walls into perinephric fat (stage III; purple). With extensive invasion (stage IV; red) they become unresectable, as well as become metastatic by seeding out. Vertically arranged with T definitions on the left and stage groupings on the right. Color bars are coded for stage: stage Tis or Ta, yellow; I, green; II, blue; III, purple; IV, red; and metastatic, black.
T-ONCOANATOMY
ORIENTATION OF THREE-PLANAR ONCOANATOMY
The isocenter of renal cancer is the renal bed, which consists of renal (Gerota's) fascia, which overlies the psoas major muscle and the quadratus lumborum musculature. The superior poles of both kidneys also lie in contact with the diaphragm. Usually, the 12th rib overlies the superior portion of the kidneys and is the only bone that is intimate anatomically. The kidney also lies opposite the transverse processes of T12 to L3 (Fig. 36.4).
T-oncoanatomy
The T-oncoanatomy is displayed in three planar views. A. Coronal, B. Sagittal, C. Transverse axial (Fig. 36.5).
• Coronal: There are many structures that overlie the kidney; however, they are of little concern oncologically because the peritoneal lining essentially excludes the visceral structures it contains from direct invasion. Nevertheless, it is important to recognize the intimate relationships of the stomach, on the left, and the duodenum, on the right, and the location of the hepatic and splenic flexures of the colon in relation to the midportions of the kidneys. The lung overlies the upper poles of both kidneys owing to the low insertion of the diaphragm, particularly during deep inspiration. One should be aware of the position of the pancreas, particularly of its head and tail and in regard to the right and left hila of the kidneys, respectively (Fig. 36.4).
• Sagittal: The kidney is encased by a fibrous capsule and is surrounded by perinephric fat. The kidney is composed of the cortex, which includes glomeruli; convoluted tubules; and the medulla, which consists of the pyramids of converging tubules and the loops of Henle. The exterior third of the kidney substance is the cortex, in contrast to the inner two thirds, which is the medulla. The medulla contains 8 to 18 striated pyramids that send finger-like rays into the cortex and end in the minor calices. The minor calices unite and form the major calices that drain into the renal pelvis. The hilus of the kidney has the pelvis, ureter, renal artery, and veins.
• Transverse: The ureteropelvic interface serves as the variable junction between pelvis and ureter, which courses inferiorly into the pelvis. The course of the ureter is such that it is first crossed anteriorly by the renal artery and vein and then the spermatic artery and vein in the male or the ovarian artery and vein in the female. In its continued descent retroperitoneally, the ureter passes anterior to the major iliac vessels. Before its insertion in the bladder, the vesical arteries and veins, as well as the uterine artery and vein, pass anteriorly (“water under the bridge”) to the ureter. There are considerable variations in the anatomic relationships of the renal ureters with renal arteries and veins owing to normal anatomic variations of embryologic development that lead to different locations of the kidneys. In addition, anomalies in their development are common and include multiple renal arteries, fetal lobulations of the kidney, deflected and bifid ureters and pelves, and horseshoe and pelvic kidneys.
Figure 36.4 | Orientation of T-oncoanatomy. The anatomic isocenter for three-planar anatomy of renal pelvis (L1, L2) and ureter is at the L1 to S5 level. A. Coronal. B. Sagittal.
Figure 36.5 | T-oncoanatomy. The Color Code for the anatomic sites correlates with the color code for the stage group (Fig. 36.3) and patterns of spread (Fig. 36.2) and SIMLAP tables (Table 36.2). Connecting the dots in similar colors will provide an appreciation for the 3D Oncoanatomy.
N-ONCOANATOMY AND M-ONCOANATOMY
N-ONCOANATOMY
The regional nodes are anterior to and surround the renal artery and vein and at the midline, para-aortic and paracaval in location. It is important to note the left testis drains to the left hilar area of the kidney and the right testis drains to paracaval nodes at the lower pole on the right. The cisterna chyli is located on the right side near the upper pole.
There are considerable variations in the anatomic relationships of the renal ureters with renal arteries and veins because of normal anatomic variations of embryologic development that lead to different locations of the kidneys. In addition, anomalies in their development are common and include multiple renal arteries, fetal lobulations of the kidney, deflected and bifid ureters and pelves, and horseshoe and pelvic kidneys (Fig. 36.6A; Table 36.4).
M-ONCOANATOMY
Common metastatic sites reflect the vascular drainage of the kidney. As noted in the patterns of spread, invasion in the renal vein and inferior vena cava is common. Pulmonary spread is very common. With continued circulation of tumor cells through the left heart, metastases to bone, brain, and liver become possible. Unfortunately, remote metastases frequently occur with this tumor because of its rich neovascularization.
Renal pelvis transitional cell cancers are characterized similarly to transitional cell cancers of uroepithelium of bladder in their ability to “seed” throughout the urinary tract. Endoscopic assessment is important to determine when renal pelvis cancer is a primary or part of a disseminated urological cancer (see Fig. 36.6B).
REGIONAL LYMPH NODES
Any amount of regional lymph node metastasis is a poor prognostic finding, and outcome is minimally influenced by the number, size, or location of the regional nodes that are involved.*
*Preceding passage from Edge SB, Byrd DR, and Compton CC, et al. AJCC Cancer Staging Manual, 7th edition. New York, Springer, 2010, p. 492.
Figure 36.6 | A. N-oncoanatomy. Renal (para-aortic) and renal pelvis and ureter. B. M-oncoanatomy. Great vessels, kidneys, and suprarenal glands.
STAGING WORKUP
RULES OF CLASSIFICATION AND STAGING
Clinical Staging and Imaging
Clinical examination is limited, and reliance on imaging is critical. The intravenous or retrograde pyelogram is essential for diagnosis. Fortunately, modern imaging is superb and includes computed tomography (CT), magnetic resonance imaging, and selective arteriography. If the primary tumor is advanced, CT of chest for lung and mediastinal nodal metastases is advised (Table 36.5; Fig. 36.7).
Pathologic Staging
Careful assessment of resected primary tumor, including kidney, appropriate lymph nodes contained within renal (Gerota's) fascia, perirenal fat, and renal vein/artery, is necessary. Partial nephrectomy needs careful study for margins.
Oncoimaging Annotations
• Intravenous pyelography and retrograde studies are still considered to be the mainstay of transitional cell carcinoma imaging, but CT is slowly replacing conventional radiographic studies.
• In a patient with transitional cell carcinoma, staging by CT is recommended.
Figure 36.7 | Axial CTs of L1 and L2 level correlate with the T-oncoanatomy transverse section (Figure 36.5C). Oncoimaging with CT is commonly applied to staging cancers, often combined with PET to determine true extent of primary cancer and involved lymph nodes 1. Superior mesenteric vein. 2. Superior mesenteric artery. 3. Duodenum. 4. Right renal vein. 5. Descending colon. J, jejunum; L, liver; LK, left kidney; RK, right kidney.
PROGNOSIS AND CANCER SURVIVAL
PROGNOSIS
The limited number of prognostic factors are listed in Table 36.6.
CANCER STATISTICS AND SURVIVAL
When considered together, the male genital and urinary systems are the major sites of malignancy. Prostate cancer alone accounts for 200,000 new patients annually. There are 100,000 new urinary tract cancers and 2.5-fold more male genital cancers: 250,000 cases annually.
The dramatic gains in survival are due to multidisciplinary achievements in screening, early detection, precise diagnoses, and effective multimodal therapies. The cancer statistics reveal perhaps the greatest gains in survival in oncology over the last five decades. For local stage I, male genitourinary tumors, all are 90% to 100% curable according to the latest Surveillance Epidemiology and End Results data: kidney, 90%; bladder, 94%; testes, 99%; and prostate, 100%. Mortality rates are declining. The pediatric Wilms’ tumor was the first malignancy in childhood to be cured, achieving 90% long-term survival, heralding the success of multimodal treatment that would be achieved in adult tumors in urology.
Figure 36.8 | Five year Observed survival renal pelvis and Ureter Cancer. Note five year observed survival is better for renal pelvis for stage I and II than renal cancer of the same stage. (Data from Edge SB, Byrd DR, Compton CC, et al. AJCC Cancer Staging Manual, 7th ed. New York, Springer, 2010, p. 494.)