Let's Talk About Bladder Cancer Causes
We've got the doctor-approved scoop on bladder cancer causes and risk factors, including lifestyle choices, family history, genetics, and more.by Linda Rodgers Health Writer
Here’s a stat you probably didn’t know: One in 40 people will get bladder cancer at some point during their lives. What you probably want to know is whether there’s any way to predict if that one in 40 will be... you. Among the many challenges of bladder cancer is the fact that it’s hard to know who will get it. Scientists are still a way from developing a genetic test for it. That said, there are several well-known risk factors—and understanding what they are can help you take action if you ever develop symptoms of the disease.
Our Pro Panel
We went to some of the nation’s top experts in bladder cancer to bring you the most up-to-date information possible.
Hooman Djaladat, M.D.
Urologic Oncologist and Associate Professor of Clinical Urology
University of Southern California Institute of Urology
Philippe Spiess, M.D.
Genitourinary Oncologist and Assistant Chief of Surgical Services
Moffitt Cancer Center
Gary Steinberg, M.D.
Urologic Oncologist and Bladder Cancer Surgeon
NYU Perlmutter Cancer Center
New York City
Without a doubt, smoking. Smoking increases your risk four- to six times, and some studies have shown that 50% of bladder cancer patients were smokers or former smokers. Your odds go up the more you smoke, but even social smokers increase their risk.
If you’re a guy, you have a 1 in 27 chance. Women have 1 in 89 odds. But every person’s chances depend on their family history, genes, and lifestyle (especially when it comes to smoking). Bladder cancer is definitely an older person’s disease, though. Roughly 90% of people diagnosed are over age 55.
Probably not. While there have been some studies that showed a link between hair coloring and bladder cancer, most studies, including reviews of previous research, have found no such risk, even for brunettes using strong permanent dyes for years. The fear probably comes from older data showing that male hairdressers had a chance of developing bladder cancer, perhaps because hair dyes in the 1970s and 80s contained cancer-causing chemicals that have since been banned.
First, they’ll rule out bacterial infections or kidney stones if you find blood in your pee by taking a urine culture. Then you may have a CT-scan or ultrasound of your bladder as well as a cystoscopy. Both tests check for tumors, but during a cystoscopy, a doctor puts a probe up your urethra and into your bladder to check for tumors. Yes, it hurts but they give you a local anesthetic to dull the pain. And it’s mercifully short—ten minutes or so and you’re done.
What Is Bladder Cancer Again?
It’s the sixth most common cancer in the U.S., and it accounts for about 3% of all new cancer cases. About 2.4% men and women will develop bladder cancer in their lifetime, and this year the National Cancer Institute estimates that there will be 81,000 new cases. It’s more common in men than women—and way more common in people over age 55, with most of those cases diagnosed in people between the ages of 65 to 84.
Bladder cancer starts the same way in men and women, though. Cells mutate, then grow quickly, eventually forming tumors. Most of the time, these tumors grow in the first layer of the bladder wall, called the inner lining (they're known as non-invasive tumors). Sometimes, though, the cancer becomes more aggressive and spreads deeper into the bladder tissue; about 4% of the time, it metastasizes to other parts of your body like your lungs.
How far and even whether your tumor will spread depends on a host of factors. What’s important to know is that bladder cancer is treatable—there are new drugs and procedures that weren’t available two years ago that have improved the quality of life for people who are diagnoed. The percentage of all bladder cancer patients who are still alive after five years is 77%, and that includes those whose cancer was advanced.
So What Causes Bladder Cancer?
No one knows what triggers the cells in your bladder to go rogue. But if you think about it, the bladder is pretty susceptible to cancer-causing chemicals, which slosh around in the urine that’s stored there. Over years, these chemicals can cause mutations in the cell’s DNA. We all have the ability to repair these DNA mutations, and we usually do. But when we can’t, through some combination of genetics, unhealthy habits, and random bad luck, these cells can become cancerous.
There are number of factors that can affect your risk of getting bladder cancer, including lifestyle and exposure to certain chemicals. Here are some of the common ones.
Smoking Definitely Ups Your Chances of Bladder Cancer
One of the biggest risk factors for bladder cancer is smoking, or living with someone who does. About 50% of all bladder cancer cases occur in smokers or former smokers, according to one study by the National Institutes of Health.
Current smokers are four times more likely to develop the most common type of bladder cancer (known as urothelial or transitional cell carcinoma or TCC) as nonsmokers—and they are more likely to have their tumors return. The more you smoke, the higher your risk. And the odds of bladder cancer increase by 22% for people who are constantly exposed to secondhand smoke.
That’s because there are about 30 to 40 known chemicals in cigarette smoke that are specifically linked to TCC, including arsenic. Why would cancer-causing chemicals you inhale get to your bladder in the first place? It’s actually a pretty straight path: After your lungs absorb these chemicals, they enter the bloodstream and go into your kidneys, which filters them and dumps them in the form of pee into your bladder and the entire urinary tract.
Quitting helps your odds—researchers discovered that post-menopausal women who’d kicked the habit 10 years earlier had cut their risk by 25%. Avoid vaping to help you do that, though. While the research is still in its earliest stages and being done in mice, scientists have found evidence to suggest that e-cigarette smoke containing nicotine can lead to genetic changes in the bladder that make it more likely cells will multiply and become cancerous.
Other Chemicals Play a Role in Causing Bladder Cancer
Aromatic amines, chemical byproducts used in making dyes, leather goods, and textiles, are another risk factor. Aromatic amines are also found in plastics, diesel exhaust, and paints (as well as cigarette smoke).
People who work around these chemicals, including house painters, machine and metal workers, truckers, and mechanics, have roughly double the risk of developing bladder cancer. So do firefighters, thanks to their exposure to these and other cancer-causing chemicals that are released in the air when buildings catch fires and they take off their respirators after the fire has been put out.
Arsenic, which is naturally found in groundwater, can raise the risk of bladder cancer by 40% if it exceeds 10 micrograms per 1.06 ounces of water. Most water systems don’t contain arsenic.
The danger comes when people get their water from wells, as is the case in New England (where the rates of bladder cancer are higher than average) as well as other parts of the country. If that’s where your H2O comes from, install a water filter designed to screen out arsenic, like the Zero Water pitcher, which did the trick according to a study published in Environmental Research.
Bladder Cancer Can Run in Families, Too
Well, maybe. Italian researchers found that bladder cancer risk doubled if you had a parent or sibling (first-degree relatives) with the disease, and it went up four times if you were a smoker as well. If a first-degree relative has any type of cancer your risk goes up 32%, according to a study done on Spanish bladder cancer patients.
Bladder cancer experts think that it’s less likely that there are specific bladder-cancer causing genes running in families. More likely, relatives inherit a sensitivity to some types of cancer-causing chemicals, making it harder for them to fix cells as they divide and change into cancerous ones.
Age Also Increases Your Chances
About 90% of bladder cancers are diagnosed in people over 55, and nearly two-thirds of those cases are diagnosed in people ages 65 to 84. The probable reason: It takes decades for chemicals or chronic infections to change the DNA of the cells in your bladder so that they can mutate, spin out of control, and form tumors.
Your Gender and Ethnicity Are Another Risk Factor
Men are more than four times as likely to get bladder cancer than women, especially white men and women. Over their lifetime, men of all races have a 1 in 27 chance compared to a woman’s 1 in 89. One theory why men are particularly susceptible: androgen receptors, which men have more of than women. These receptors help the body respond to testosterone and other hormones, by, say, controlling sex drive or hair growth. But they can also spur tumor growth, too, especially in prostate cancer.
Still, even though women have lower odds of developing bladder cancer, they tend to be diagnosed when the cancer is more advanced and have higher death rates, as do African-American men and women.
Why the discrepancy among women (both white and black)?
Partly it has to do with anatomy—women’s bladder walls are thinner, making it easier for a tumor to grow into the muscle tissue, where cancer is harder to treat. But it’s also because doctors tend to dismiss symptoms, like blood in the urine, as urinary tract infections, postponing a diagnosis until much later.
African-American men also die at higher rates than whites. Their tumors tend to be more aggressive, though no one knows why, but in general blacks have less access to good care—from specialists and cancer centers—along with not-so-great health insurance policies that make access to care harder.
UTIs Can Also Raise Your Risk of Bladder Cancer
So can having kidney stones, probably because chronic infections create inflammation, and there’s a link between inflammation and cancer. Another chronic condition that’s been associated with bladder cancer is type 2 diabetes, though only in men. People with diabetes tend to have more UTIs, so that could be the connection, as well as a faulty immune system thanks to the disease.
Since there’s no screening test for bladder cancer, you have to know the signs and symptoms of bladder cancer if you have any of these risk factors. One of the earliest signs is blood in the urine. If you see it, call your doctor so you can be checked out at once.
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Vaping and Bladder Cancer Risk: Proceedings of the National Academies of Sciences (2019). “Electronic-cigarette smoke induces lung adenocarcinoma and bladder urothelial hyperplasia in mice.” pnas.org/content/116/43/21727
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Water Filters and Arsenic: Environmental Research (2017). “Effectiveness of table top water pitcher filters to remove arsenic from water.” sciencedirect.com/science/article/pii/S0013935117303419
Family History: Cancer Epidemiology (2017). “Family history of cancer and the risk of bladder cancer: A case-control study from Italy.” ncbi.nlm.nih.gov/pubmed/28363161
Cancer Epidemiology, Biomarkers and Prevention (2007). “Risk of Bladder Cancer Associated with Family History of Cancer: Do Low-Penetrance Polymorphisms Account for the Increase in Risk?” cebp.aacrjournals.org/content/16/8/1595
Men and Bladder Cancer: Journal of the National Cancer Institute (2007). “Promotion of Bladder Cancer Development and Progression by Androgen Receptor Signals.” academic.oup.com/jnci/article/99/7/558/2522371
Racial Disparities: Cancer (2009). “Sex and Race in Bladder Cancer: What We Have Learned and Future Directions.” acsjournals.onlinelibrary.wiley.com/doi/full/10.1002/cncr.23997
Diabetes and Bladder Cancer: Medicine (2017). “Diabetes Mellitus and the Risk of Bladder Cancer.” ncbi.nlm.nih.gov/pmc/articles/PMC5704818/
Hair Dyes and Bladder Cancer: Open Access (2012). “Personal hair dye use and the risk of bladder cancer: a case–control study from The Netherlands.” link.springer.com/article/10.1007/s10552-012-9982-1
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