Bladder Cancer

Bladder cancer is one of the most frequently diagnosed malignancies, with estimated 68,810 new cases in the US in 2008. It is the fourth most common cancer in men, accounting for 6.9% of all cancers, and 10th most common cancer in women, accounting for 2.6% of all cancers. Thus, men have significantly higher risk of bladder cancer than women. Excessive exposure to cigarette smoke and industrial chemicals in men had been suggested to result in the development of bladder cancer. However, our recent report shows molecular evidence that male hormone (androgen) plays an important role in bladder cancer, which may explain the gender-specific difference in incidence.

As described in the previous posts, bladder cancer can be divided into two distinct types: superficial, often low-grade (less aggressive) tumors, and invasive, mostly high-grade (more aggressive) tumors. Although most of the superficial tumors are not life-threatening disease, the patients frequently (50-70%) suffer from tumor recurrence with occasional (10%) progression to muscle invasion after surgery. In contrast, patients with invasive tumor frequently need more aggressive treatment. Therefore, early detection of bladder cancer for both initial diagnosis and recurrence is important to improve patients’ prognosis.

Cystoscopy is the “gold standard” for the detection of bladder cancer, but is an invasive and relatively expensive procedure. Urine cytology (examination of collected urine under a microscope to look for cancerous cells) is a non-invasive test widely utilized with cystoscopy for both screening and surveillance for recurrence. It is generally good for detecting high-grade bladder tumors. One limitation, however, is the inability to definitively identify low-grade cancer cells. In addition, the accuracy of diagnosis in urine cytology is dependent on the level of expertise of the cytopathologist. It is noteworthy that due to lifelong need for monitoring recurrence, the typical cost per bladder cancer patient from diagnosis to death was estimated to be the highest among all cancers ($96,000-$187,000 in the US). Thus, new non-invasive tests for detecting bladder cancer will minimize patient discomfort, reduce costs, and eventually lead to reducing bladder cancer mortality.

There are four urine-based tests for bladder cancer approved by the US Food and Drug Administration (FDA). In my posts, I will describe these tests, as well as other markers that have been shown to be clinically useful, some of which could be substitutes of cystoscopy and/or cytology.

Hiroshi Miyamoto, MD, PhD