Although it has long been known that smoking is one of the top risk factors for developing bladder cancer, a new study shows that the intensity of smoking also influences the behavior of the disease biologically (Cancer 2013;119:756-765).
“Bladder cancer patients who smoked longer and heavier (i.e. had higher smoking intensity) are more likely to have aggressive disease and poor outcomes than those who did not,” the study's lead author, Anirban P. Mitra, MD, PhD, Senior Research Associate in the Department of Pathology and Laboratory Medicine and the Center for Personalized Medicine at the Keck School of Medicine of the University of Southern California, explained in an email. “This is one of the initial studies to show that not only does smoking cause bladder cancer, but it also influences the cancer's course.”
The study defined a nine-protein biomarker panel that predicts disease outcome independent of clinical variables and smoking intensity—and the study also analyzed the smoking histories of 212 patients with primary urothelial carcinoma of the bladder to identify how smoking intensity was related to those outcome-predicting molecular alterations. The key findings:
- Patients who smoked the longest (for more than 30 years) had the greatest risk of having the disease-causing cyclooxygenase-2 alteration;
- Increased smoking intensity was associated with poorer outcomes (shorter survival);
- Increasing smoking duration and number of cigarettes smoked daily were associated with worse disease prognosis; and
- Independent of the presence of the individual bladder cancer marker alterations, smoking intensity still retained its association with poorer outcomes—and helped more adequately predict outcomes.
“The combination of smoking intensity and information of these biomarker alterations were most informative of patient outcomes. This suggests that knowledge of prior smoking habits and molecular alterations in the tumor may help identify high-risk patients who may need more aggressive therapy,” Mitra said.
Getting Clued In
The findings are relevant for members of both the urology and cancer care teams, Mitra said. Both groups need to document details about their patients' tobacco use: in the oncology setting so that bladder cancer patients can be stratified into risk groups to better manage treatments, and in a urology setting so that smokers are encouraged to quit.
The tobacco and lung cancer link gets lots of attention. But, research has shown that the general public is not well informed about the association between cigarette smoking and bladder cancer risk—for example, a recent study showed that barely more than a third of the adults surveyed were aware of the connection (The Journal of Urology 2008;180:31-37).
Many patients and health care providers overlook the fact that tobacco's 4,000-plus chemicals, in addition to getting absorbed into the lungs, also get absorbed into the blood, get filtered by the kidneys, and concentrate in the urine. Those sitting carcinogens wreak havoc on the bladder cells until they get flushed out. Increasing fluid consumption will help empty the bladder more often to get the carcinogens out of the bladder—and actually helps reduce bladder cancer risk (for smokers and non-smokers).
And—for patients who need more convincing—the other benefits of quitting smoking are that:
- Heart rate drops (almost immediately),
- Blood pressure drops (almost immediately),
- Circulation and lung function improve (in two weeks to three months after quitting),
- Coronary heart disease risk decreases (by 50 percent as soon as one year after quitting), and
- Risk of stroke reduces to that of a non-smoker five years after quitting.
Julie Derossett, RN, BAS, is an oncology/urology nurse at the University of Michigan Comprehensive Cancer Center. Sarah DiGiulio is the Assistant Editor ofOT.