More than half of bladder cancers in the U.S. are the result of smoking, and 90 percent of smokers with the disease are aware of the connection, according to a new study.

“Bladder cancer is actually the second most common smoking-related cancer, second only to lung,” said lead author Dr. Jeffrey C. Bassett of Kaiser Permanente Southern California in Anaheim.

Although previous studies had suggested that few people understood the connection between bladder cancer and tobacco, this new study found the opposite, he said.

“Bladder cancer patients smoking at diagnosis appear to accept that their own smoking caused their cancer, positioning them for a more motivated (and more likely successful) attempt at quitting,” Bassett said.

He and his team surveyed 1,198 men and women who had been diagnosed with bladder cancer between 2006 and 2009 in the California Cancer Registry about their smoking history, and 790 completed the survey.

About half were former smokers, and many had quit at least 10 years before their cancer diagnosis.

Nineteen percent of the patients were current smokers. They were more often younger, less educated and single compared to former or never smokers.

The surveys contained a list of ten potential causes of bladder cancer, like tobacco use, alcohol, age, family history and sexually transmitted disease, and asked respondents to identify those that could cause cancer, and later to identify which caused their own cancer based on what they knew.

Almost 70 percent of respondents said tobacco could cause cancer, making it the most cited cause in the survey. Next most common were alcohol and age.

Ten percent of current smokers said smoking did not cause bladder cancer, and 16 percent said it had not been the cause of their own cancer, according to results in Cancer.

Current and former smokers most often attributed their cancer to tobacco. They cited urologists as the most common source of information about the link.

More than 12 million new cases of bladder cancer occur annually worldwide, making it the seventh most common cancer for men and seventeenth for women, according to a review paper in 2009 in the World Journal of Urology. The disease is three to four times more common in developed countries and 90 percent of cancers are diagnosed past the age of 55.

Some patients have a good prognosis and can keep their own bladder, while those with advanced disease may need their bladders removed and have a poor prognosis, Bassett told Reuters Health by email.

“Our data suggests that patients smoking at bladder cancer diagnosis are most likely to quit if the conversation regarding smoking and bladder cancer happens at diagnosis,” he said. “Cancer diagnoses are known to motivate the newly diagnosed to change the unhealthy behaviors that were contributory.”

This study did not assess how aware people are of the link to bladder cancer before diagnosis, which is also important, said Dr. Courtney M.P. Hollowell, Chairman of Urology at Cook County Health and Hospitals System in Chicago.

“The diagnosis of tobacco related malignancies represents a teachable moment,” Hollowell told Reuters Health by phone. “Urologists really have the opportunity to make a large public health impact.”

Even when caught early, bladder cancer often recurs, making it one of the most costly cancers to treat in the U.S., said Hollowell, who was not involved in the new study.

As with other cancers, quitting at diagnosis reduces the risk that cancer will recur or spread, Bassett said.

“The reality is that everybody should stop smoking,” said Dr. Alan M. Nieder, of Columbia University's Division of Urology at Mount Sinai Medical Center in Miami Beach, Florida.

“Urologists in particular should use every office visit to tell patients not to smoke,” Nieder told Reuters Health by phone. He was not part of the new study.

If the risk of lung or bladder cancer doesn’t convince a younger patient to quit, stressing the risk of erectile dysfunction or facial aging may, he said.

“The Surgeon General has now linked 18 different types of cancer to tobacco use,” Bassett said. “Only two of these are well known in general public – lung cancer and cancer of the head/neck.”

For people at risk for one of the numerous lesser-known tobacco-related cancers, every healthcare interaction is an opportunity to individualize the harms of continued tobacco use and motivate them to make a successful attempt to quit, he said.