Bladder cancer is a broad term used to describe all types of cancers affecting the urinary bladder. It includes several distinct types, each with unique characteristics, risk factors, and treatment approaches. Below, we provide a comprehensive overview of bladder cancer based on the latest medical knowledge.
Types of Bladder Cancer
- Transitional Cell Carcinoma (TCC):
- Also called urothelial cell carcinoma (UCC), TCC is the most common primary neoplasm of the bladder and the entire urinary system.
- It can be superficial (70-80% of cases) or invasive (20-30%). Superficial tumors are often papillary, while invasive tumors may spread into deeper layers of the bladder wall.
- Squamous Cell Carcinoma (SCC):
- Accounts for 3-8% of bladder cancers.
- More common in regions where schistosomiasis infections are prevalent.
- Often associated with chronic irritation, such as from bladder stones or indwelling catheters.
- Adenocarcinoma:
- Rare, accounting for about 1% of bladder cancers.
- Often linked to chronic irritation, bladder exstrophy, or persistent urachal remnants.
- Small Cell Carcinoma:
- Extremely rare, with a poor prognosis.
- Often diagnosed at an advanced stage.
Staging and Diagnosis of bladde cancer
The Vesical Imaging-Reporting and Data System (VI-RADS) was introduced in 2018 to standardize bladder cancer staging using multiparametric MRI. It assigns a score from 1 to 5 based on imaging findings:
- VI-RADS 1: Muscle invasion is highly unlikely.
- VI-RADS 2: Muscle invasion is unlikely.
- VI-RADS 3: Muscle invasion is equivocal.
- VI-RADS 4: Muscle invasion is likely.
- VI-RADS 5: Invasion of muscle and beyond the bladder is very likely.
Diagnostic Tools:
- Cystoscopy and Biopsy: Primary methods for diagnosis and local tumor staging.
- Imaging:
- CT: Useful for assessing tumor size, nodal status, and distant metastases.
- MRI: Superior for local staging, especially in distinguishing T1 from T2 tumors.
- Ultrasound: Limited role in diagnosis or staging.
- PET: Not suitable for primary diagnosis due to urinary excretion of FDG but useful for evaluating metastases.
Clinical Presentation of bladder cancer
- Hematuria (blood in the urine) is the most common symptom, which may be macroscopic or microscopic.
- Tumors near the vesicoureteric junction may cause ureteral obstruction and hydronephrosis, presenting as flank pain.
- Tumors near the urethral orifice may lead to bladder outlet obstruction and urinary retention.
- Systemic symptoms of metastatic disease may also be present in advanced cases.
Pathology and Risk Factors of bladder cancer
- Pathology of bladder cancer:
- Superficial TCCs are often papillary, while invasive TCCs may involve deeper layers of the bladder wall.
- SCC and adenocarcinoma are often associated with chronic irritation or infection.
- Risk Factors:
- Smoking (aromatic amines in tobacco smoke).
- Exposure to industrial chemicals (e.g., arylamines, polycyclic aromatic hydrocarbons).
- Chronic bladder irritation (e.g., from stones, catheters, or infections).
- Chemotherapy agents like cyclophosphamide.
Radiographic Features of bladder cancer
- CT:
- Bladder TCCs appear as focal wall thickening or masses protruding into the lumen.
- Calcifications may be present.
- CT can distinguish T3b (stranding/nodules in perivesical fat) and T4 tumors (invasion of adjacent structures).
- MRI:
- T1: Isointense to muscle.
- T2: Slightly hyperintense to muscle; useful for assessing muscle layer integrity.
- T1 C+ (Gd): Shows enhancement.
- Urography:
- Useful for assessing the entire urinary tract for synchronous tumors.
Treatment and Prognosis of bladder cancer
- Superficial Tumors:
- Treated with transurethral resection (TURBT) and intravesical therapy (e.g., BCG or mitomycin C).
- High recurrence rate (70% within 3 years), but excellent prognosis with a 5-year survival rate of 94%.
- Invasive Tumors:
- Require radical cystectomy, often combined with chemotherapy or radiotherapy.
- Prognosis is poorer, with a 5-year survival rate of 6% for metastatic disease.
- Recurrence:
- 2-4% of patients with bladder TCC may develop TCCs in the renal pelvis or ureter.
Differential Diagnosis of bladder cancer
- Other bladder tumors (e.g., squamous cell carcinoma, adenocarcinoma).
- Benign prostatic hypertrophy or prostate cancer.
- Ureteric jets (may simulate a filling defect).
- Cystitis glandularis.
Specifics of Rare Bladder Cancers
- Squamous Cell Carcinoma (SCC):
- Often solitary and large at diagnosis, with muscular wall invasion common.
- Associated with schistosomiasis, chronic irritation, or infection.
- Adenocarcinoma:
- Subclassified as primary (non-urachal or urachal) or secondary (metastatic).
- Urachal adenocarcinoma is characterized by a midline, infraumbilical mass with peripheral calcification.
- Small Cell Carcinoma:
- Rare, with a poor prognosis (<10% 5-year survival for localized disease).
- Imaging findings overlap with TCC.
Conclusion
Bladder cancer is a diverse group of malignancies with varying presentations, risk factors, and treatment options. Accurate diagnosis and staging, particularly using the VI-RADS system, are critical for effective management. If you or a loved one is experiencing symptoms or has been diagnosed with bladder cancer, consult a specialist to discuss the best treatment plan tailored to your specific condition.