Bladder cancer is the ninth most common cancer worldwide and the fourth most common tumor type among American men and represents a health burden disproportionate to its size. The disease consists of several types of malignancies originating in the epithelium of the urinary bladder. 2.5 million people suffer from it, with 430,000 newly diagnosed each year. In 2010 there were 170,000 cases of death from bladder cancer globally, up from 115,000 cases 20 years before.
Bladder cancer occurs about 4 times more frequently in men than in women. It is primarily a disease of the elderly population with about 90% of cases occurring in people age 55 or older. The median age of diagnosis is 73 years.
Signs and symptoms
Signs and symptoms of bladder cancer include blood in the urine (hematuria) and disturbances in bladder habits.
Risk Factors that have been identified for bladder cancer include smoking and work exposure to certain chemicals.
Diagnosis, Staging and Treatment of Early Stage Bladder Cancer
Bladder cancer is usually diagnosed on initial presentation via trans-urethral cystoscopy, or visualization of the lining of the bladder, and biopsy. The most important features of tumors diagnosed in this way are the depth of invasion of the primary lesion(s) into or through the lining of the bladder, and the grade of the lesion when examined pathologically.
The depth of invasion of the tumor (or tumors, as multiple tumors can arise simultaneously) is the major determinant of initial prognosis and treatment. Tumors are categorized according to the extent to which they penetrate the anatomic layers of the bladder. Tumors which are contained in the bladder epithelium are denoted carcinoma in situ (CIS). Tumors which arise from the surface of the epithelium, and extend only into the bladder lumen, are denoted Ta lesions. Those that involve the layer beneath the epithelium, or the lamina propria, are T1 lesions. Ta and T1 lesions are called papillary tumors. Together, CIS, Ta and T1 lesions, that involve the lining of the bladder but not its muscle layer, are called non-muscle invasive bladder cancer, or NMIBC. Tumors that invade the muscle, penetrate through it, or extend completely through the bladder into the pelvis (T2, T3, and T4 tumors, respectively), are collectively muscle invasive bladder tumors.
The distinction between NMIBC and muscle invasive disease is a crucial one, as is determines initial treatment and prognosis. About 70% of patients present with NMIBC bladder tumors. For these patients, initial therapy includes trans-urethral resection (TUR) of papillary lesions, and treatment with various therapies that are introduced into the bladder through the urethra, intravesically. Such therapies include chemotherapy or biologic therapy with agents such as Bacille Calmette Guerin (BCG), which is attenuated tuberculosis bacteria. The recurrence rate after these treatments is high, and is dependent on the categorization of the initial tumor and its pathologic grade, but overall is approximately 70%.
For patients whose tumors invade the muscle, the standard of care is the removal of the bladder, or radical cystectomy. For those patients who initially have NMIBC, but whose tumors recur after surgical and medical approaches to therapy, radical cystectomy is also usually the therapy of choice.
The standard approach to therapy for early stage disease, and especially NMIBC, renders the quality of life for patients with this condition difficult. Treatment and monitoring is characterized by surgery, intravesical treatment, and continual monitoring by frequent cystoscopy. Recurrence is common, and is often a prequel to more invasive surgical therapy, or systemic therapy as well.
Bladder cancer has the highest lifetime cost per patient of all cancers. The high recurrence rate and ongoing invasive monitoring requirement are the key contributors to the economic and human toll of this disease. For these reasons, new therapies for early stage bladder cancer are needed.