In the United States, the prevalence of bladder cancer has increased greatly over the last few decades, with more than 60,000 new cases diagnosed annually. It occurs more frequently in men than in women, and is usually diagnosed in adults over 60 years old. When bladder cancer is diagnosed and treated in the early stages, the chances of survival are excellent.
More than 90% of newly diagnosed bladder cancers are urothelial cell carcinomas (cancers originating from the unique lining of the urinary tract). Most patients have superficial cancer that involves the very inner layers of the bladder wall. Less than one fourth have invasive disease that involves the deeper layers of the bladder wall, and less than 5% present with metastatic disease, defined as spread beyond the confines of the bladder.
What causes bladder cancer?
Cancer-causing agents (carcinogens) are most often responsible for bladder cancer. Bladder cancer is highly associated with tobacco smoking. Even if one stopped smoking years ago, the risk is related to the quantity of tobacco smoked over the years. The carcinogens that are present in tobacco are absorbed through the lungs, into the bloodstream, and are filtered through the kidneys directly into the bladder, where their prolonged contact time with the lining of the bladder leads to cancerous changes.
Certain occupations put people at a greater risk for bladder cancer because of exposure to chemicals, including: hairdressers, painters, machinists, printers, and those who work with dyes, textiles, rubber, leather, and petrochemicals.
What are the symptoms of bladder cancer?
Bladder cancer most commonly manifests with blood in the urine, either visible or microscopic (seen only under microscopic magnification). It may also cause irritative lower urinary tract symptoms including urgency, frequency, discomfort with urinating, and urinary leakage.
How is bladder cancer diagnosed?
The evaluation for blood in the urine includes imaging, cytology, and cystoscopy.
- Imaging tests are means of visualizing the anatomy of the urinary tract, typically through ultrasound, computerized tomography (CT), or magnetic resonance imaging (MRI).
- Cytology is a microscopic inspection of a urine sample by a pathologist for the presence of abnormal or cancerous cells that slough off the lining of the bladder, similar to a Pap smear done to screen for cervical cancer.
- Cystoscopy is a visual inspection of the entire lower urinary tract (bladder and urethra) using a tiny, flexible, lighted instrument attached to a camera and monitor.
When a bladder tumor is identified on cystoscopy, attention is directed to the number of tumors present, their size, location within the bladder, and physical appearance.
Once a bladder tumor is recognized, it needs to be removed and sent for pathological evaluation. This is performed under general or spinal anesthesia via cystoscopy, using an electric loop which is used to remove the area of concern as well as cauterize (use electricity to coagulate tissue) the underlying and adjacent tissue, both to stop bleeding and further destroy tumor cells.
The biopsied tissue is carefully examined by a pathologist, who will provide valuable information regarding malignancy vs. benignity, the type of tumor, depth of tumor, and grade of tumor.
Types of Bladder Cancer
The biopsy information will enable the staging of the bladder cancer, a means of classifying the cancer. Staging of bladder cancer is as follows:
- Ta: Superficial cancer is found only in polyps (papillary) on the surface of the inner lining of the bladder.
- Tis: Carcinoma-in-situ. Tumor is found only in flat lesions on the surface of the inner lining of the bladder.
- T1: Tumor is found in the connective tissue below the lining of the bladder but has not spread to the bladder muscle.
- T2: Tumor has spread to the muscle layer deep to the lining of the bladder.
- T3a: Tumor has spread through the muscular wall of the bladder into the fatty tissue layer as identified under microscopic examination.
- T3b: Tumor has spread through the muscular wall of the bladder into the fatty tissue layer and is capable of being identified without a microscope.
- T4: Tumor has spread to the prostate in men and to the uterus or vagina in women, or to the pelvic or abdominal wall in either gender.
How is bladder cancer treated?
Bladder cancer often needs to be treated with a surgical procedure involving either partial or complete removal of the urinary bladder. If the entire bladder needs to be removed, the ureters (tubes that conduct the urine from the kidneys to the bladder) need to be diverted to a piece of intestine that is either attached to the skin to a collection bag or attached to the urethra (neo-bladder or “reconstructed” bladder). At times, in lieu of surgery, chemo-radiation can be utilized (a combination of radiation therapy provided by the radiation oncologist and chemotherapy provided by the medical oncologist).
Superficial cancers are usually managed with cystoscopy, with regular “surveillance” due to the high predilection for recurrence. It’s important to have frequent check-ups (every 3 months for the first year after initial diagnosis), consisting of periodic urinalysis, urine cytology, imaging, and cystoscopy. If surveillance does not demonstrate any recurrences, the interval between follow up can gradually be increased (to every 6 months in the 2nd year; if there are no recurrences, to an annual check-up). If a recurrence is found, treatment must be repeated and the surveillance frequency then starts anew with the every 3-month cycle.
To help prevent recurrence, under certain circumstances it is beneficial to use a medication that is instilled in the bladder on a weekly basis—this is especially useful when many tumors are present, in the presence of a high-grade tumor, or cancers that have recurred. It’s particularly useful for carcinoma-in-situ (CIS), a variant of bladder cancer that is very superficial, flat, yet of a high-grade pathological nature. The medication of choice is tuberculosis vaccine—BCG (bacillus Calmette Guerin), which is a live, attenuated (weakened) form of tuberculosis bacteria!