May is Bladder Cancer Awareness Month, a cancer that affects 4 times as many men as women

Bladder Cancer Awareness Month: Smoking & Cancer Risk

All About Bladder Cancer

May is Bladder Cancer Awareness Month. This is a good time to learn about bladder cancer, risk factors, prevention, and treatment. Bladder cancer is the fourth most common cancer for men, but is much less common for women. There are about four times more men with bladder cancer than women. It is estimated that about 83,000 new cases of bladder cancer will be diagnosed in the United States in 2024, and about 16,000 people will die from bladder cancer.

Bladder cancer cases have decreased slightly in recent years, but mortality rates in men have stayed about the same. Most people diagnosed with bladder cancer are older, and 9 out of 10 cases are in people aged 55 years or older.

The bladder is a hollow organ in the lower pelvis. Its main job is to store urine. The bladder has flexible walls and a lining made up of cells called urothelial cells. Bladder cancer begins when cells in the urinary bladder start to grow out of control. As more cancerous cells grow, a tumor can develop, and cancer can also spread to other parts of the body. 

The most common type of cancer is urothelial carcinoma, also known as transitional cell carcinoma (TCC), which is cancer in the urothelial cells of the bladder lining. Urothelial cells also make up other parts near the bladder and urinary tract, such as part of the kidneys, ureters (tubes that connect the bladder and kidneys and where urine travels through), and the urethra (where urine is released from the bladder). Bladder cancer can often spread to these other parts of the body.

Bladder cancer treatments depend on the type and stage of the cancer. The most common treatment is surgery, with or without other treatments, such as chemotherapy and radiation. When bladder cancer is more advanced and invasive, the most common surgery is a cystectomy. In this procedure, part or all of the bladder is removed. A cystectomy is often accompanied by chemotherapy before or after surgery.

The Number One Bladder Cancer Risk Factor

Researchers don’t know exactly what causes bladder cancer, but they have identified some factors that increase your risk of developing bladder cancer. Some risk factors include smoking, workplace exposure to industrial chemicals, use of certain medications, arsenic in drinking water, not drinking enough fluids, bladder birth defects, family history, and genetic mutations. Because some risk factors are related to lifestyle factors, there are some ways to prevent or lower your risk for getting bladder cancer. Some potential prevention strategies include quitting smoking, limiting exposure to chemicals, drinking fluids and staying hydrated, and eating a diet rich in fruits and vegetables.

While smoking is most often thought of as related to lung cancer, smoking is actually linked to at least 15 different cancers, including bladder cancer. Smoking causes about 20% of all cancers and about 30% of all cancer deaths in the United States. Smoking is the number one risk factor for bladder cancer. In fact, people who smoke are about three times more likely to develop bladder cancer than non-smokers. Researchers estimate that smoking causes about half of all bladder cancers.

Researching the Smoking Connection

But how did scientists discover that smoking is linked to bladder cancer risk? That’s where research comes in! Observational studies can provide a wealth of information about cancer risk factors. Observational studies observe processes and outcomes that are already occurring organically. Researchers don’t try to make one outcome occur or change any exposures. Instead, they observe and do not intervene. Researchers will analyze these observations and outcomes and see if any relationships exist between a factor (such as smoking) and a health outcome (such as development of bladder cancer).

One type of observational study is cohort studies. Cohort studies follow a group of people with a common characteristic over time and observe outcomes. This can occur by following people forward in time, or looking back to the past. One such study involving bladder cancer was published in the 1970s. The study looked back into the past with a cohort of people who died from bladder cancer. The study team then analyzed rates of smoking. The study found that bladder cancer deaths sharply increased in men born after 1870. This increase corresponds to a dramatic rise in smoking in men in the early 1900s. Women did not experience this increase in bladder cancer, perhaps due to a much slower rise in the popularization of smoking for women. 

After this and similar studies in the late 1900s, smoking was thought to be a top risk factor for bladder cancer. This discovery was further cemented in the 2000s. A cohort study sent survey questionnaires with lifestyle questions to older adults in the United States in 1995-96. More than 566,000 surveys were sent back. The survey participants were followed until bladder cancer diagnosis, death, loss to follow-up, or until December 2006. The study team then identified bladder cancer cases in the cohort and analyzed questionnaire responses to see if any risk factors or relationships could be identified. The study found that cigarette smoking (both past and current) greatly increased risk of bladder cancer for both men and women. Current smokers were about four times more likely to develop bladder cancer than never smokers, and former smokers were about two times more likely to develop bladder cancer than never smokers. Cigars and pipe smoking also increased bladder cancer risk, even in those who did not smoke cigarettes. Overall, the study estimated that smoking was attributed to at least 50% of bladder cancer cases.

Bladder Cancer Prevention

Research helps us learn more about cancer and the different ways cancer is caused and factors that increase cancer risk. This is so important because if we know what increases risk, we can develop prevention strategies to reduce risk! The best way to prevent bladder cancer is to quit smoking or never start. If you’re a current smoker, it’s never too late! Learn more about smoking cessation today.