D'Arcy Little, MD, CCFP
Director of Medical Education,
York Community Services,
Toronto, ON

Munir A. Jamal, MD, FRCSC
Staff Urologist,
Credit Valley Hospital,
Mississauga, ON

Introduction

Epidemiology:
Cancer of the urinary bladder is essentially a disease of the elderly. The median age at diagnosis is 69 years for males and 71 years for females, and more than one-third of cases occur in patients over the age of 75 years of age.^1,2 The incidence of transitional cell carcinoma (TCC) of the bladder, the most common subtype of bladder cancer, accounting for over 90% of cases, is rising and currently ranks as the fourth highest new cancer diagnosis in men.³ However, the mortality rate of this disease has fallen over the last two decades.¹ The following review article will address the epidemiology, natural history, clinical presentation, and treatment of this disease, with an emphasis on issues pertaining to elderly patients. (See Figure 1)

Bladder cancer is unique among human neoplasms in that it has been associated with several distinct etiological factors.⁴ Risk factors related to the development of TCC, in addition to age, include tobacco smoking and occupational exposures in the dye, rubber, textile, and leather industries.

A new technique has been designed that will hopefully aid physicians in detecting the early stages of bladder cancer. Researchers at Yale University have developed a urine test that identifies a protein that is found in bladder cancer cells.

Currently, the methods for the detection of bladder cancer rely on cytological examination of urine and a cytoscopy, where a scope is passed through the urethra into the bladder to examine the bladder walls. The cytoscopy is both expensive and painful for the patient. In a study of 158 patients, the group found that all patients with new or recurring bladder cancer tested positive for the presence of the protein survivin in their urine. All healthy patients tested negative for the protein and patients with other cancers including kidney, prostate, cervical and vaginal cancer also all tested negative for survivin.

The survival rate for bladder cancer is quite high, with a five-year survival rate of 93%. However, most patients will have a recurrence of the disease, and once diagnosed and treated, patients must undergo a cytoscopy every three months for two years to ensure that the cancer has not returned. In addition, they must have an annual upper tract study where the kidneys, urethra and bladder are examined for the presence of malignant cells.

Several other studies have investigated a marker to detect bladder cancer, and until now telomerase has been the new marker. Until a method is developed that is 100% specific and sensitive, cytoscopy will remain the only reliable method to test for bladder cancer.

People over the age of 40 are at a higher risk for bladder cancer, and men are at higher risk than are women. There is also an increased rate of this cancer in smokers when compared to non-smokers. For a full article on the diagnosis and treatment of bladder cancer in the elderly, please see next month's issue of Geriatrics & Aging.

Source

1. Smith, SD et al. Urine detection of survivin and diagnosis of bladder cancer. JAMA 2001; 285:324-328.

Screening for cancers of internal organs is notoriously difficult, and by the time the disease has progressed to symptoms in the patient that indicate cancer, the outlook is often poor. In the October 30th issue of The Lancet, Kai Stoeber and colleagues from Cambridge, UK, with the Cancer Research Campaign, describe the result of a new screening test for cancer of the urinary tract that does not involve invasive procedures. The test detects the minichromosome maintenance (Mcm5) protein involved in the replication of DNA that occurs when cells divide. The protein is expressed at a high concentration in many cancers, probably because the cancer cells divide rapidly. The investigators used an immunofluorometric assay to show that the protein was detected in cells shed in the urine of all eight patients with a cancer of the urinary tract, and in only one of 28 control individuals. This particular test could be automated, and because the Mcm5 protein is over-expressed in other cancers, the same test could potentially be used to screen for these.