Prostate cancer recurrence rate not greatly affected by smoking

San Francisco-Cigarette smoking is associated with more advanced prostate tumors among men undergoing radical prostatectomy, but there appears to be little difference between smokers and non-smokers when it comes to biochemical recurrence, according to the results of a multicenter, retrospective analysis.

Researchers from several institutions analyzed 1,267 subjects from the Shared Equal Access Regional Cancer Hospital (SEARCH) database. All underwent prostate surgery between 1998 and 2008.

About one-third of the men in the study were active smokers at the time of surgery. Current smokers were significantly younger (p<.001) and more likely to be African-American (p<.001); had lower body mass indices (p<.001) and prostate volumes (p=.002); and had a higher percentage of positive biopsy cores (p=.039), higher preoperative PSA (p=.003), and higher incidence of extracapsular extension (p=.003) and seminal vesicle invasion (p=.029).

"This finding suggests smoking is not an independent risk factor for recurrence after surgery," said first author Daniel Moreira, MD, a fellow in urologic oncology at Duke University, Durham, NC, working with Stephen Freedland, MD, and colleagues. "In addition to our study, several others have found that smoking is associated with more aggressive disease. So the compounded evidence suggests smoking may be involved in prostate cancer progression."

Dr. Moreira added that another explanation for the findings might be that, because smoking is associated with such comorbidities as coronary artery disease and systemic hypertension, smokers may be discouraged from aggressive and potentially curative treatments like surgery. That, in turn, might explain the higher rates of disease progression among smokers.

"Unfortunately, these hypotheses are still speculative, and further study is required to elucidate the biologic and behavioral components of the observed association," he said at the AUA annual meeting.

Smoking, BCR risk 'unrelated'

Multivariable analysis showed that smoking was associated with an increased risk of biochemical recurrence when adjusted only for body mass index (p=.008), although the association was no longer statistically significant following adjustment for multiple preoperative characteristics.

What's more, additional adjustment for features such as tumor grade and stage rendered smoking unrelated to biochemical recurrence.

"Given our relatively modest sample size, we were unable to detect small differences between the two groups," Dr. Moreira said.

While Dr. Moreira was not aware of any other studies that have investigated the association of smoking and recurrence after surgery, he noted that such connections have been thoroughly investigated in lung cancer. Several studies have correlated smoking with worse outcomes in men with lung tumors and have connected the intensity of smoking with poor tumor differentiation, higher treatment failure rates, and higher cancer mortality.

Results from the study were published online in Urology (April 8, 2010).