Case-Based Review

Urothelial Carcinoma: Muscle-Invasive and Metastatic Disease


 

References

Introduction

Bladder cancer is by far the most common cancer of the urinary system. Worldwide, approximately 450,000 new cases are diagnosed and 165,000 deaths are caused by bladder cancer each year.1 In the United States and in Europe, the most common type of bladder cancer is urothelial carcinoma (also referred to as transitional cell carcinoma), which accounts for more than 90% of all bladder cancers in these regions of the world. The remainder of bladder cancers are divided among squamous cell carcinomas, adenocarcinomas, small cell carcinomas, and, even more rarely, between various other nonepithelial tumors (eg, sarcoma).

Bladder cancer is classically thought of as a disease of the elderly, with a median age at diagnosis of 69 years in men and 71 years in women.2 The incidence of bladder cancer increases with age: in persons aged 65 to 69 years, incidence is 142 per 100,000 men and 33 per 100,000 women, and in those older than 85 years the rate doubles to 296 per 100,000 men and 74 per 100,000 women.3 The incidence is 3 times greater in men than in women.4

Urothelial carcinoma is traditionally categorized by its degree of invasion into the bladder wall: superficial (non-muscle-invasive), muscle-invasive, or metastatic disease. At the time of diagnosis, most patients have non-muscle-invasive disease (~60%); about 4% of all patients present initially with metastatic disease.5 This article focuses on metastatic bladder cancer, but muscle-invasive disease is discussed as well.

The most important factor contributing to the development of urothelial carcinoma is tobacco smoking. The risk of developing bladder cancer is 4 to 5 times higher in smokers as compared to nonsmokers, with some variation according to sex.6 Quantity of smoking exposure also plays a role, with heavy smokers demonstrating a higher likelihood for high-grade tumors with muscle invasion (or beyond) when compared to light smokers.7 Another important risk factor is occupational exposure to industrial materials, such as carpets, paints, plastics, and industrial chemicals. This type of exposure may be responsible for, or at least contribute to, the development of approximately 20% of urothelial carcinomas. Other risk factors for urothelial carcinoma include but are not limited to prior radiation to the pelvis, prior upper tract urothelial malignancy, human papillomavirus infection, and prior bladder augmentation.

Diagnosis and Staging

Case Presentation

A 63-year-old man with a past medical history of diabetes, deep vein thrombosis, occasional alcohol use, and regular pipe tobacco use presents to his primary care physician with complaints of hematuria. He reports that his urine was a dark red color that morning, which had never happened before. The patient is hemodynamically stable upon evaluation in the office, and a point-of-care urinalysis dipstick is strongly positive for blood. He is referred to a urologist for further evaluation.

In the urology office, urine microscopy is notable for more than 50 red blood cells (RBCs) per high-power field with normal RBC morphology. Flexible cystoscopy performed in the office reveals a single 2-cm, sessile, verrucous, nodular lesion located on the anterior bladder wall. A urine sample and a bladder wash specimen are sent for cytology evaluation. The patient is scheduled to undergo a complete transurethral resection of bladder tumor (TURBT) later that week with samples sent to pathology for evaluation.

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