Andrew Siegel, MD Blog #92
Bladder cancer is such a common public health problem that I thought it would be worthy of an educational blog. Few people realize that its occurrence is more highly linked to tobacco than is lung cancer.
In the USA, the incidence of bladder cancer has increased greatly over the last few decades, with more than 60,000 new cases diagnosed each year. It is the fourth most common cancer in men and the eighth in women. With the exception of skin cancers, bladder cancers are the most frequently recurring cancer, with up to 70% of patients experiencing recurrence. The occurrence of bladder cancer increases with age and is three times more common in men than women. 80% of newly diagnosed individuals are 60 years of age or older. At present, about 20% of patients die each year, but when the disease is diagnosed and treated in the early stages, the chances of survival are excellent, highlighting the importance of a timely and accurate diagnosis. More than 90% of newly diagnosed bladder cancers are urothelial cell carcinomas (cancers originating from the unique lining of the urinary tract).
The majority of patients with newly diagnosed bladder cancer have superficial cancer that involves the very inner layers of the bladder wall. About 20% have invasive disease that involves the deeper layers of the bladder wall. The remaining 5% present with metastatic disease, defined as spread beyond the confines of the bladder.
The highest prevalence of bladder cancer is in industrialized nations. 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 are at higher risk for bladder cancer because of exposure to chemicals—these include: hairdressers, painters, machinists, printers, and those who work with dyes, textiles, rubber, leather, and petrochemicals.
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.
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. A papillary appearance consists of fronds (finger-like projections floating in the bladder) with a narrow attachment to the bladder lining versus a sessile appearance, in which the tumor appears solid and is widely attached to the bladder lining.
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 biopsed 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. Again, the vast majority of bladder tumors are urothelial cancers, referring to the cells that line the bladder. A minority of bladder tumors are squamous cell cancers or adenocarcinomas. Depth refers to the degree that the cancer is growing into the bladder wall. Bladder cancers are broadly categorized into superficial and deep. Superficial tumors are largely confined to the bladder lining and superficial layers and do not penetrate the muscle layer of the bladder, whereas deep tumors have “roots” that penetrate the muscular wall of the bladder. Tumor grade refers to how much the microscopic appearance of the cancer deviates from the microscopic appearance of healthy bladder cells. Low-grade cancers are similar in cellular appearance to normal bladder cells and generally behave in an indolent (slow) fashion versus high-grade cancers that can often behave aggressively. Other factors of prognostic importance are the number of tumors present, the size of the tumors, and their physical characteristics.
In general, the best prognosis is for a solitary, small, superficial, low-grade papillary tumor and the worst prognosis is for multi-focal (originating from many different areas of the bladder), large, invasive (deep), sessile, high-grade tumors.
The biopsy information will enable the staging of the bladder cancer, a means of classifying the cancer. It is extraordinarily unlikely for a superficial cancer to cause lymph node or distant spread, these events occurring with much greater likelihood with more deeply invasive cancers.
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.
Superficial cancers are usually managed with cystoscopy, with regular “surveillance” due to the high predilection for recurrence. It is imperative 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 is 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!
Muscle-invasive cancers most often need to be treated with a major surgical procedure involving either partial or complete removal of the urinary bladder. In the circumstance that 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 (ileal conduit) 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).
Bladder cancer often behaves as two separate types of diseases—one that typically presents as multiple, superficial papillary tumors that have a tendency to recur but are not lethal (similar to many skin cancers), versus another, more deadly form characterized by high-grade, non-papillary, muscle-invasive tumors that have a tendency to metastasize. Fortunately, the vast majority of bladder cancers are the superficial type.
Andrew Siegel, M.D.
Author of Promiscuous Eating: Understanding and Ending Our Self-Destructive Relationship with Food: www.promiscuouseating.com
Available on Amazon in paperback or Kindle edition
For an educational video on bladder cancer that I have done, please go to the following link: http://www.youtube.com/watch?v=WvEOcCzw2gQ
Blog subscription: A new blog is posted every Saturday morning. On the lower right margin you can enter your email address to subscribe to the blog and receive notifications of new posts by email. Please avail yourself of these educational materials and share them with your friends and family.