Urinary Bladder Cancer
SadhnaVerma, MD • Arumugam Rajesh, MBBS, FRCR • Srinivasa R. Prasad, MD • Krishnanath Gaitonde, MD • Chandana G. Lall, MD Vladimir Mouraviev, MD, PhD • Gunjan Aeron, MD • Robert B. Bracken, MD • Kumaresan Sandrasegaran, MD
90% of urinary bladder tumors are urothelial in origin (TCC)
Most common etiologic factors for urothelial cancer are
cigarette smoking (causative factor in 50-60% of men and in 1/3 of female)
occupational exposure to chemical carcinogen's such as anilyne dyes
therapeutic irradiation of neighbouring organs
use of alkylating agents
Genetic predisposition is RARE
6-8% are SCC
Most common risk factors for SCC:
long term catheterization
urinary tract calculi
chronic infection by Schistosoma hematobium
Nearly all cases are INVASIVE
Arise from urachus
Can carry worse prognosis than urothelial tumors
Urinary bladder is an extraperitoneal structure (peritoneum covers only the superior surface of the bladder - bladder dome)
80-85% NOT invading muscle
(superficial or papillary)
low grade lesions
arise from hyperplastic epithelium
rarely evolve into an invasive cancer
high recurrence rate - 50%
25% of urothelial tumors have mixed histology - small cell neuroendocrine, micro papillary (resembling serous papillary cancer of the ovary, sarcomatous and pasmocytoid)
20-25% Invading muscle
arise from severe dysplasia or carcinoma in situ
Have higher histologic grade
low recurrence rate in comparison with non-muscle invasive variety
The 4 defined layers of the bladder wall are:
urothelium - lines the bladder lumen (thin)
highly vascular lamina propria (submucosa), thickness varies from the degree of distention
muscular propria (detrusor muscle, smooth muscle fibers)
outermost serosa (is formed by a loose layer of connective tissue)
CLINICAL STAGING AND MANAGEMENT
Patients present with painless hematuria
TREATMENT DECISIONS AND PROGNOSIS
Are based on:
the depth of muscle invasion
degree of differentiation of tumor
presence or absence of metastatic disease
Muscle invasive disease
TURBT is performed for:
complete resection of superficial bladder tumors
deep biopsy - to assess muscle invasive tumors
Note: Cross-sectional imaging is usually performed afterwards for disease staging in patients who are thought to have solid tumors.
5-year surveillance rate
STAGE T4 - 27%
STAGE T2 - 66%
BLADDER CANCER STAGING
T1: tumor invades connective tissue under the epithelium (surface layer)
T2: tumor invades muscular layer
T2a: superficial muscle (inner layer)
T2b: deep muscle (outer layer)
T3: tumor invades perivesical fat
T3a: invasion is detected microscopically
T3b: invasion is detected macroscopically
T4: tumor is invading neighboring organs (prostate, vagina etc.)
Most common site of nodal metastasis is
Common iliac nodes are considered to be in a secondary drainage region and indicate N3 disease.
N1: Metastasis in a single lymph node smaller than 2 cm in size
N2: Metastasis in a single lymph node greater than 2 cm or smaller than 5 cm in size, or multiple lymph nodes smaller than 5 cm in size
N3: Metastasis in a lymph node greater than 5 cm in size
Mx: Distant metastasis can not be evaluated
M0: No distant metastasis
M1: Distant metastasis
In patients with hematuria CT urography has a sensitivity of over 90% for the diagnosis of bladder cancer.
CT does not allow confident diagnosis of flat lesions and lesions at the bladder base adjacent to the prostate gland in patients with BPH.
A major difficulty is to differentiate:
tumor recurrence from inflammatory wall thickening that occurs following endovesical chemotherapy.
scar tissue after TURBT
NCCN guidelines for postcystectomy surveillance:
every 3-6 months for the first 2 years
Conventional CT and MRI are only moderately accurate in the diagnosis and local staging of bladder cancer; cystoscopy and pathologic staging remain the standard of reference.
The study of the bladder requires:
high spatial resolution
thin sections (3 mm)
FOV 28-32 cm
Optimizing echo time (usually 60-80 msec) is crucial for achieving a high contrast-to-noise ratio, which is important in assessing the depth of bladder wall involvement
Dynamic CE MRI
The normal bladder wall does not enhance avidly on the early gadolinium-enhanced images.
In the early phase (20 sec after contrast material injection), bladder carcinomas tend to enhance more than the surrounding bladder wall.
The bladder tumor, mucosa, and submucosa enhance early, but the muscle layer maintains its hypo intensity and enhance late (60 sec)
Optimal bladder distention is achieved by instructing the patient to void approximately 2 hours prior to imaging.
High-resolution T2 WI of the bladder obtained in the three orthogonal planes with a small FOV and a large matrix are used to evaluate the detrusor muscle for tumor depth and invasion of the surrounding organs
DWI in bladder cancer has been evaluated in terms of diagnosis, staging, prediction of histologic grade, and assessment of the efficacy of induction chemotherapy.
Urinary bladder cancer is a heterogeneous disease with a variety of pathologic features, cytogenetic characteristics and natural histories. It is the 4th most common malignancy in men and 10th most common cancer type in women. Urinary bladder cancer has a high recurrence rate, necessitating long term surveillance after initial therapy.
Urinary bladder diverticula is a risk for development of cancer because of stasis. And because of absence of muscle in diverticula wall there is increased risk of perivesical fat invasion by the cancer.