Smoking May Double Risk for Recurrence in Some Patients With Bladder Cancer

Patients with non-muscle invasive bladder cancer who currently smoke or previously smoked should consider quitting to possibly improve health outcomes in survivorship, according to an expert.

Patients with non-muscle invasive bladder cancer who have smoked or currently smoke may have an increased risk of disease recurrence, according to recent study results.

“Cigarette smoking was associated with nearly two-fold, three-fold increased risk of recurrence in patients diagnosed with non-muscle invasive bladder cancer,” said Marilyn L. Kwan, lead author on the study and senior research scientist in the division of research at Kaiser Permanente in Oakland, California, in an interview with CURE®.

She explained that tobacco is a known risk factor for developing bladder cancer and it accounts for up to 50% of diagnoses. However, the role of tobacco smoking on bladder cancer prognosis is unclear.

Kwan and colleagues sought to evaluate this association among 1,472 patients with non-muscle invasive bladder cancer an average of 2.3 months after diagnosis. This included patients who were former smokers (59.4%), current cigarette smokers (7.5%), smoked pipes and/or cigars only (13.7%), used e-cigarettes (4.4%) or used marijuana (24.7%).

Results – which were published in JAMA — demonstrated that longer cigarette smoking duration and more pack-years were associated with a higher risk of recurrence in a dose dependent matter. The highest risk was found in patients who had smoked for 40 or more years or 40 or more pack-years (how to measure how much a person has smoked over a period of time, calculated by the number of packs of cigarettes per day multiplied by the number of years the person has smoked).

Kwan explained that tobacco and nicotine are carcinogens (a substance capable of causing cancer in living tissue) that can remain in the urine of the bladder. In addition, these carcinogens can continue to play a role in the increased risk for recurrence after effective treatment and while a person is in survivorship.

“What this means for patients is that, indeed, cigarette smoking is a critical exposure for patients, (and) prior smoking can influence your risk of recurrence of bladder cancer,” Kwan told CURE®. “And it’s important, if you are current smoker at the time of your diagnosis of non-muscle invasive bladder cancer, to really consider seriously to stop smoking, as smoking continues to play a role in in your health outcomes as a bladder cancer survivor.”

There was no association of having ever smoked, being a former or current cigarette smoker and years since quitting smoking with recurrent risk. Additionally, no association with smoking pipes, cigars, e-cigarettes or marijuana were found.

Moreover, 102 patients were offered smoking cessation interventions, and 57 went on to receive it after diagnosis. Women were more likely to engage in such interventions than men (76.7% versus 44.7%, respectively).

Kwan is hopeful that the results of this study will lend more support to urologists who treat patients with bladder cancer as another piece of evidence of why current smokers should quit.

“The main takeaway is that, one, tobacco smoking is a modifiable behavior in patients (and) that if you are a current smoker and (were) just diagnosed with bladder cancer, (you) really seriously (should) consider quitting smoking,” she concluded. “This will most likely improve your health outcomes as a survivor of non-muscle invasive bladder cancer.”

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