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

Iatrogenic factors

  • 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

  • non-functioning bladder

  • urinary tract calculi

  • chronic infection by Schistosoma hematobium

Nearly all cases are INVASIVE

Rest (rare)

Adenocarcinoma

Arise from urachus

Can carry worse prognosis than urothelial tumors

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 

  • multifocal

  • arise from hyperplastic epithelium

  • good prognosis

  • 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

(non-papillary)

  • 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:

  1. urothelium - lines the bladder lumen (thin)

  2. highly vascular lamina propria (submucosa), thickness varies from the degree of distention

  3. muscular propria (detrusor muscle, smooth muscle fibers)

  4. 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.

Radical cyctectomy

5-year surveillance rate

  • STAGE T4 - 27%

  • STAGE T2 - 66%

BLADDER CANCER STAGING

T 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.)

N Staging

M Staging

Most common site of nodal metastasis is

  • obturator nodes

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

IMAGING CONSIDERATIONS

CT urography

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

POSTTREATMENT SURVEILLANCE

NCCN guidelines for postcystectomy surveillance:

 

  • every 3-6 months for the first 2 years

    • urine cytology

    • chest radiography

    • abdomino-pelvic imaging 

Conclusion:

  • 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. 

MR Imaging

The study of the bladder requires:

  • high spatial resolution

  • thin sections (3 mm)

  • large matrix

  • 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

Diffusion weighted-imaging

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. 

©2018 by Dr Anar Kazimov