An Oft-Overlooked Treatment Option in Patients With Prostate Cancer: Smoking Cessation

A new metaanalysis suggests that quitting smoking, or even reducing tobacco intake, reduces the risk of dying from prostate cancer.

In a metaanalysis published on September 18, 2014 in the journal European Urology, Islami and colleagues identified a worsened risk of dying from prostate cancer in smokers, and a further magnified risk of death with increasing levels of tobacco intake.¹

Investigators searched PubMed and other science databases to identify 51 qualifying studies, with the data combined using random effects methods and reported as relative risk scores. Study data included an aggregation of 50,349 cases of prostate cancer with 11,823 deaths from the disease.¹

Patients with prostate cancer were matched to approximately 4.1 million patients without prostate cancer to analyze the effect of lifestyle factors, such as smoking. Upon metaanalysis, smoking was found to increase the risk of death from prostate cancer by approximately 24% (95% CI: 18% to 31%). This estimate was consistent across studies, with little heterogeneity between study estimates.¹

In this analysis of tobacco use and prostate cancer mortality, researchers identified smoking as a modifiable risk factor in the progression of prostate cancer. In addition, unlike previous studies, this analysis explored the relationship between total exposure to tobacco and the risk of developing and dying from prostate cancer.¹

Investigators found that patients who smoke 20 or more cigarettes per day were at a 20% greater risk of dying from prostate cancer than patients smoking fewer than 20 cigarettes per day (P = .02). In other words, cutting down smoking intake may have beneficial effects, which is an important, new finding.

Many patients with prostate cancer may be unwilling to stop smoking entirely, but may be willing to smoke less—especially if smoking less reduces the risk of dying from prostate cancer.¹

In a finding inconsistent with prior research, this metaanalysis identified a lower risk of developing prostate cancer among current smokers. Smokers without prostate cancer were approximately 10% (95% CI: 4% to 15%) less likely to develop a new case of prostate cancer than nonsmokers.¹

Importantly, however, this result inconsistent between studies, and prior studies have shown a 6% (95% CI: 0% to 12%) increase in the risk of developing new cases of prostate cancer in smokers.²

Current guidelines from the European Association of Urology recommend cessation of smoking as an important step in reducing the risk of prostate cancer mortality.³ Unlike these guidelines, the current National Comprehensive Cancer Network guidelines make no mention of smoking cessation as a therapeutic option for patients with newly diagnosed prostate cancer.⁴

Smokers who develop prostate cancer may be reluctant to quit smoking, but as results of this metaanalysis show, quitting smoking or even cutting down intake may reduce the risk of dying from prostate cancer. These results may help patients understand that the damaging effects of smoking proceed even after cancer has developed.

References:

• Islami F, Moreira DM, Boffetta P, Freedland SJ. A Systematic Review and Meta-analysis of Tobacco Use and Prostate Cancer Mortality and Incidence in Prospective Cohort Studies. Eur Urol. 2014.
• Daniell HW. A worse prognosis for smokers with prostate cancer. J Urol. 1995;154(1):153-157.
• Heidenreich A, Bastian PJ, Bellmunt J, et al. EAU guidelines on prostate cancer. part 1: screening, diagnosis, and local treatment with curative intent-update 2013. Eur Urol. 2014;65(1):124-137.
• Mohler JL, Kantoff PW, Armstrong AJ, et al. Prostate cancer, version 2.2014. J Natl Compr Canc Netw. 2014;12(5):686-718.