Bladder cancer is the fourth leading cause of cancer in American men, accounting for more than 12,000 deaths annually. It was one of the first malignancies in which carcinogens were recognized as an important factor in its cause. Currently, cigarette smoking is by far the most common cause of bladder cancer, although occupational exposure to arylamines has been implicated in the past. Gross or microscopic hematuria is the most common sign at presentation. Initial radiologic evaluation usually includes the excretory urography (intravenous pyelography), although further evaluation of the renal parenchyma with ultrasound or computed tomography scanning has been advocated by some. These radiologic studies are unable to provide adequate bladder imaging, and thus cystoscopy is required for the diagnosis of bladder cancer. Most bladder cancers present as "superficial" disease, confined to the bladder mucosa or submucosal layer, without muscle invasion. Superficial tumors consist of papillary tumors that are mucosally confined (Ta), papillary or sessile tumors extending into the lamina propria (T1), and carcinoma in situ, which occurs as "flat" mucosal dysplasia, which can be focal, diffuse, or associated with a papillary or sessile tumor. The natural history of these pathologic subtypes differ significantly. Most superficial tumors (60% to 70%) have a propensity for recurrence after transurethral resection. Some (15% to 25%) are at high risk for progression to muscle invasion. Most superficial tumors can be stratified into high- or low-risk groups depending on tumor stage, grade, size, number, and recurrence pattern. It is important to identify those tumors at risk for recurrence or progression so that adjuvant intravesical therapies can be instituted. Many intravesical chemotherapeutic agents have been shown to reduce tumor recurrence when used in conjunction with transurethral tumor resection. Unfortunately, however, none of these agents have proved to be of benefit in preventing disease progression. Most are given intravesically on a weekly basis, although many studies suggest that a single instillation immediately after transurethral resection may be as good as a longer course of therapy. Although all of these drugs have toxicity, they usually are well tolerated. Intravesical bacille Calmette-Guérin (BCG) is an immunotherapeutic agent that when given intravesically is very effective in the treatment of superficial transitional cell carcinoma. Compared with controls, BCG has a 43% advantage in preventing tumor recurrence, a significantly better rate than the 16% to 21% advantage of intravesical chemotherapy. In addition, BCG is particularly effective in the treatment of carcinoma in situ, eradicating it in more than 80% of cases. In contrast to intravesical chemotherapy, BCG has also been shown to decrease the risk of tumor progression. The optimal course of BCG appears to be a 6-week course of weekly instillations, followed by a 3-week course at 3 months in those tumors that do not respond. In high-risk cancers, maintenance BCG administered for 3 weeks every 6 months may be optimal in limiting recurrence and preventing progression. Unfortunately, adverse effects associated with this prolonged therapy may limit its widespread applicability. In those patients at high risk in whom BCG therapy fails, intravesical interferon-α with or without BCG may be beneficial in some. Photodynamic therapy has also been used but is limited by its toxicity. In patients who progress or do not respond to intravesical therapies, cystectomy should be considered. With the development of orthotopic lower urinary tract reconstruction to the native urethra, the quality of life impact of radical cystectomy has been lessened.
ASJC Scopus subject areas
- Cancer Research