You may have heard it from physicians, from family members who have been doing their reading, or from spinal cord injury survivors who go to other doctors or who were treated at different hospitals or rehabilitation centers: “You’re going to develop cancer of the bladder if you keep that catheter in.” Are they right? No one knows. Is the risk of bladder cancer higher in spinal cord injury survivors? Yes. Is it further increased by using an indwelling catheter? Again, yes. Is the risk unreasonable? Only you can make that decision. Are there things you can do to reduce that risk? Probably. The key lies in knowing your own risks, understanding your choices, and making the necessary tradeoffs, based on solid information.
Three Pieces to the Puzzle:
There are three different pieces to the bladder cancer puzzle. All of them are important for understanding the big picture. First, there is incidence. Just how much more common is bladder cancer among spinal cord injury survivors? How great are the chances of developing it? Second, there are risk factors. What are some of the things that increaseand decrease the risk for bladder cancer? Finally, there is you. What can you do to change, lessen, or just understand those risks. It’s a complicated picture; if you still have questions after reading this, get more information.
The truth is that bladder cancer is more common than in the general population. However, in reality, it’s a very rare disease in nondisabled people that becomes somewhat more common among SCI survivors.
In the general population, the incidence of bladder cancer is about 1 person in every 5000.1 That’s less than 1%; less even than 1/10th of 1%. In spinal cord injury, the most commonly quoted overall incidence seems to be around 150 in every 5000, or 3%. This is an average, based on the findings of many different studies. Some studies showed lower cancer rates. For example, a 1991 study of 2900 spinal cord injury survivors at three US hospitals found eight cases (less than 1%) of bladder cancer;1 in an earlier study at Stoke Mandeville Hospital in England, there were 25 cases in 6744 persons (4%);2 and out of 1052 new admissions at a veterans hospital in Virginia, ten diagnoses of bladder cancer (1%) were found.3 Finally, at Craig Hospital, when the records of 2660 former patients with SCIs were examined, 13 cases of bladder cancer were identified (less than 1%).
So, just for some perspective: even though bladder cancer may be 100 times more frequent in SCI survivors than in the general population, it still isn’t extremely common. A non-disabled woman's chance of developing breast cancer is greater1 in 8than an SCI individual has of developing bladder cancer. And, within SCI itself, complications like pressure sores, spinal cord cysts, hyperreflexia, and kidney failure are much more common, while illnesses like heart disease and respiratory complications account for far more deaths.4
There’s more to know: indwelling cathetersurethral catheters, “foleys,” suprapubic
cystostomies, “super-tubes”do tend to bear the blame for this increased risk. However, that may be an over simplification of the problem.
In fact, it seems likely that several different factors interact to increase the bladder cancer risk for SCI survivors. Indeed, even catheter-free survivors, or those who use intermittent catheterization, have higher bladder cancer rates than the general population.2,5
Bladder Irritation is the key: Most of the factors increasing this risk for bladder cancer relate to one thing: irritation of the bladderboth chronic and repeated. Many scientists and researchers suspect that spinal cord injury, because of the way it changes the urinary system and alters the environment inside the bladder, may increase the amount and types of irritation the bladder is subject to.
One big irritant is urinary tract infections; the more frequent and more severe they are, the more irritation they may cause. And, they seem to play a role regardless of whether there's a catheter present. In addition to the irritation they cause, some researchers suspect that urinary tract infections cause the release of a substance in the bladder, called nitrosamine.2,6 This substance, itself, may enhance the development of cancerin much the same way that cigarette smoke may enhance cancer formation in the lungs. Indeed, the effects of bladder infections and nitrosamines may partly explain why people who don’t use catheterswhether able-bodied or SCI survivorssometimes get bladder cancer, too.7
Bladder stones are also potential irritants.6,8,9. Stones have been studied less than urinary tract infections, but their role seems obvious. First, they’re believed to occur because of some irritationa stray hair, grit, sediment already present in the bladder. Second, when not removed, bladder stones become a source of irritation, causing mechanical or physical irritation within the bladder and fostering urinary tract
infections, which themselves cause irritation.
Smoking may be another form of irritation, and smokers do face an increased risk of bladder cancer.6,7 Are spinal cord injured smokers at even greater risk? Possibly. Carcinogens, like those found in cigarette smoke, may be carried in the urine. One researcher found evidence to suggest that the presence of urinary tract infectionswhich many SCI survivors havemay make the bladder even more susceptible to these carcinogens.6
The catheter’s role: Still, without a doubt, the catheter itself is the largest potential source of irritation. In some people, tumors have been seen inside the bladder where the catheter rubs, and in the path where the catheter lays.5,10 The incidence of cancer is still much higher among those who do have indwelling catheters than among those who use external collectors, intermittent catheter-ization, credé, and most other types of bladder management. In the Craig Hospital study of 2660 SCI survivors, indwelling catheters were found to increase the risk of cancer 3.8 times, compared with SCI survivors who did not use indwelling catheters.
The biggest catheter-related risk factor seems to be how long the catheter has been in place. Some researchers have reported that cancer rates go up the longer people use indwelling catheters.9,11 In the Craig study, the cancer risk in the 2660 people studied was only 0.2% during the first 10 years. But, by 30 years, in a group that was relatively small in size, the risk of bladder cancer had risen to 9% for indwelling catheter users.
Another catheter-related risk that has been suggested is a factor called the “era of care.” Some physicians believe that people most at risk are those who were injured long agobefore modern antibiotics, anticholinergic drugs, and catheters made from safer, non-rubber materials, were available. Some even believe that bladder cancer incidence rates will be lower among more recently injured SCI survivors who are treated with today’s more modern methods.
Diagnosing Bladder Cancer:
The most common symptom of bladder cancer is blood in the urine: blood that is
chronic or recurring and that does not appear to be related to a urinary tract infection. However, because many other thingsless serious than cancercan cause blood to appear in the urine, the best way to monitor the bladder is by having a urologist examine it.
With an instrument called a cystoscope, the urologist can see inside the bladder. If any suspicious areas are noted, he or she may recommend a biopsya procedure in which a small piece of the bladder wall is scraped away and examined carefully under a microscope. Though biopsies may cause some blood-tinged urine for a day or two, they’re not usually painful and can be done fairly simply at the same time as the cystoscopy itself.
Biopsies: It’s fairly common for the biopsy report to come back with a diagnosis of squamous metaplasia. This is a medical term for a microscopic cellular change that is often seen in the bladder. Some scientists believe that microscopic squamous metaplasia is a warning sign of a particular kind of bladder cancersquamous cell carcinoma.11 Both squamous metaplasia and squamous cell carcinoma are believed to result from those already-described chronic irritations inside the bladderstones, UTIs, catheters. Therefore, these scientists argue, both of these conditions should be of concern to SCI survivors, especially those who manage their bladders with indwelling catheters.
However, the truth is, researchers do not agree on this issue. Many others argue that
while squamous metaplasia may be a precursor to cancer it is not always something to worry about.
Why the controversy? Several reasons. Squamous metaplasia is extremely common among both nondisabled people and spinal cord injury survivors.3,12 Many people have squamous metaplasia and never develop bladder cancer. In one study of 450 non-disabled people who already had squamous metaplasia, none developed squamous cell cancer!12
Among SCI survivors, as many as 80% of catheter users may have squamous metaplasia,8 and common sense dictates that not all are going to develop bladder cancer. In another Craig Hospital study, for example, 172 spinal cord injury survivors had bladder biopsies. All of them had indwelling catheters most were suprapubics. More than half of the 172 people who were tested did have squamous metaplasia. None of them were found to have squamous cell carcinoma.
What does all this mean? Before we talk about what you can do to minimize your risk for bladder cancer, let’s sift through what’s been said so far:
Regardless of whether you are catheter-free or use an indwelling catheter, probably the best advice is to be meticulous in all aspects of your bladder management program. Follow all physician recommendations about medications, fluid intake, cleanliness, monitoring, and follow-up. Most important, stay up-to-date. Ongoing research may make new information available that could be beneficial to you.
If you do happen to have an indwelling catheter, here are some specific things you can do to reduce your risk:
Decrease the amount of irritation in your bladder:
Prevent infections & stones:
Decrease your exposure to cancer-causing agents in general:
You can't undo your spinal cord injury, but taking these steps will help minimize your risk for bladder cancer. To come back to the big question: Should you abandon your indwelling catheter program for one that is less invasive? There's no easy answer. If everything else is equal and your bladder could work just as well without an indwelling catheter, and if your independence and quality of life would not be affected by the program you chose, it probably would be safer to go with a program that does not involve an indwelling catheter. But, it's seldom that simple.
The key questions to ask yourself are:
Answering these questions is difficult and complicated. Get the information you need about your own unique situation so you can weigh the tradeoffs. Research, your doctor, your family and friends, and other SCI survivors can help you, but only you can make the final decision.
References for this article:
1 Bickel A, Culkin DJ, Wheeler JS (1991). Bladder cancer in spinal cord injury patients The Journal of Urology146:1240-2.
2 El Masri WS, Fellows G (1981) Bladder cancer after spinal cord injury. Paraplegia 19:265-70.
3 Broecker BH, Klein FA, Hackler RH (1981). Cancer of the bladder in spinal cord injury patients. The Journal of Urology 125:196-7.
4 Whiteneck GG (1993). Learning from recent empirical investigations. Aging with Spinal Cord Injury. NY: Demos
5 Sene AP, Massey JA, McMahon RTF, Carroll RNP (1990) Squamous cell carcinoma in a patient on clean intermittent self-catheterisation. British Journal of Urology 65(2):213-4.
6 Dolin PJ, Darby SC, Beral V (1994) Paraplegia and squamous cell carcinoma of the bladder in young women: findings from a case-control study. British Journal of Cancer 90:167-8.
7 Kantor AF, Hartge P, Hoover RN, Narayana AS, Sullivan JW, Fraumeni JF (1984). Urinary tract infections and risk of bladder cancer. American Journal of Epidemiology 11:510-5.
8 Locke JR, Hill DE, Walzer Y (1985). Incidence of squamous cell carcinoma in patients with long-term catheter drainage. The Journal of Urology 133:1034-5.
9 Kaufman JM, Fam B, Jacobs SJ, Gabilondo F, Yalla S, Kane JP, Rossier AB (1977). Bladder cancer and squamous meta-plasia in spinal cord injury patients. The Journal of Urology 9(3):317-20.
10 Kaye MC, Levin HS, Montague DK, Pontes JE. (1992) Squamous cell carcinoma of the bladder in a patient on intermittent self-catheterization Cleveland Clinical Journal of Medicine 59(6):645-6.
11 Esrig D, McEvoy K, Bennett CJ (1992). Bladder cancer in the spinal cord-injured patient with long-term catheterization: a casual relationship Seminars in Urology10(2):102-8.
12 Widran J, Sanchez R, Grunn J (1974). Squamous metaplasia of the bladder: a study of 450 patients. The Journal of Urology 112:479.
13 Lamm DL, Riggs DR, Shriver JS, vanGilder PF, Rach JF, DeHaven JI (1994). Megadose vitamins in bladder cancer: a double-blind clinical trial. Journal of Urology. 51:21-6.
This is one of more than 20 educational brochures developed by Craig Hospital while it was a federally-funded Rehabilitation Research & Training Center on Aging with Spinal Cord Injury. The opinions expressed here are not necessarily those of the funding agency, the National Institute on Disability and Rehabilitation Research of the US Department of Education.
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