Smoking at Time of Treatment Worsens Prostate Cancer Outcomes

June 8, 2018

Current smokers at the time of primary treatment for localized prostate cancer have a higher risk of negative outcomes, including recurrence, metastasis, and mortality.

Current smokers at the time of primary treatment for localized prostate cancer have a higher risk of negative outcomes, including biochemical recurrence (BCR), metastasis, and cancer-specific mortality, according to a new literature review and meta-analysis.

“The effect of tobacco consumption on the incidence of prostate cancer is still a matter of debate,” wrote study authors led by Beat Foerster, MD, of the Medical University of Vienna in Austria. “Nevertheless, the association between cigarette smoking and prostate cancer mortality seems to be robust.”

The new meta-analysis sought to help explain those discordant findings, and investigate the associations between smoking status and prostate cancer outcomes. It included 16 published papers and 11 studies with a total of 22,549 prostate cancer patients. The results of the analysis were published in JAMA Oncology.

In total, 4,202 patients (18.6%) were current smokers at the time of primary curative treatment; 18,347 (81.4%) were nonsmokers, including both former and never smokers. For the full meta-analysis cohort, the follow-up period was 72 months.

Among the studies that investigated BCR, 4,656 patients (21.4%) experienced a BCR. Current smokers had a higher risk of experiencing a BCR compared with nonsmokers, whether they had undergone radical prostatectomy or radiotherapy, with a hazard ratio (HR) of 1.40 (95% CI, 1.18–1.66; P < .001). When current smokers were compared with only never-smokers, the association was higher, with an HR of 1.59 (95% CI, 1.40–1.80; P < .001). Being a former smoker also increased the risk of BCR, with an HR of 1.19 (95% CI, 1.09–1.30; P < .001).

Three of the studies provided data on metastases; in those, 90 of 2,086 patients (4.3%) developed metastatic disease. Current smoking was associated with an increased risk, with an HR of 2.51 (95% CI, 1.80–3.51; P < .001). When only former smoking status was assessed, there was no association with metastasis, with an HR of 1.61 (95% CI, 0.65–3.97; P = .31).

Among an evaluable subset of 7,924 patients, 654 of them (8.3%) died of prostate cancer. Again, being an active smoker during primary therapy was significantly associated with increased risk of prostate cancer–specific death, with an HR of 1.89 (95% CI, 1.37–2.60; P < .001). Former smokers, in contrast, were not at higher risk, with an HR of 1.05 (95% CI, 0.81–1.37; P = .70).

“These findings encourage physicians to use the diagnosis and treatment of localized prostate cancer as a teachable moment to counsel patients to stop smoking,” the authors wrote. “Further studies with clear definitions of the study population and a precise assessment of the smoking exposure are needed to clarify the association of smoking cessation with long-term oncologic outcomes.”