More good reasons to stop smoking if you are at risk for prostate cancer

New data from a research team at Stanford University in California have further confirmed the effect of “heavy” smoking on the diagnosis of men with prostate cancer.

Although there are no clear data to demonstrate that — on its own — smoking is a basic risk factor for prostate cancer, it is becoming increasingly clear that smokers who are diagnosed with prostate cancer are at increased risk for more aggressive forms of this disorder.

Earlier this year, we reported that Kenfield et al. had published detailed information on the impact of smoking on diagnosis, treatment, and recurrence of prostate cancer from the Health Professionals Follow-up Study. In their new study, Ngo et al. have investigated the impact of smoking on pathologic outcomes and biochemical recurrence in a cohort of men undergoing radical prostatectomy.

Ngo et al. identified 630 patients who had a radical prostatectomy between 1989 and 2005 and for whom detailed smoking histories were also available. The patient cohort included 321 smokers and 309 non-smokers. Biochemical recurrence was defined as a postoperative PSA level of ≥ 0.1 ng/ml. [Editor’s note: Why can the surgery community not all agree on a fixed PSA level that clearly establishes biochemical recurrence after radical prostatectomy?]

The results of retrospective analysis of the pathology and follow-up data available for these 630 men show the following:

  • The average (median?) volume of cancer in the prostate on post-surgical pathology was
    • 2.54 ml for smokers
    • 2.16 ml for non-smokers
    • And the difference was statistically significant (P = 0.016)
  • The average (median?) volume of high grade cancer in the prostate on post-surgical pathology was
    • 0.58 ml for smokers
    • 0.28 ml for non-smokers
    • And the difference was again statistically significant (P = 0.004)
  • “Heavy” smokers (i.e., men with a ≥ 20 pack-year history) had a greater risk of biochemical recurrence on univariate survival analysis.
  • Smoking predicted a greater risk of biochemical recurrence — of about 1 percent per pack-year smoked.

It is interesting to us that the authors are now defining “heavy” smoking as a history of ≥ 20 packs per year, i.e., just over one cigarette per day. Those of us old enough to remember what a “heavy” smoker used to be defined as think more in terms of 365 packs per year or higher, i.e., 20 or more cigarettes per day! On that basis, the risk for biochemical recurrence of a man diagnosed with prostate cancer who smokes a pack of cigarettes a day is 365 percent higher than a non-smoker. (However, we suspect that that level of risk may be an exaggeration compared to a man smoking just half a pack of cigarettes a day.)

Whatever the details of the actual risk level, it is clear from this study and from the prior work of Kenfield et al. that smoking regularly at even a relatively low level is not a good thing to have been doing if you subsequently get diagnosed with prostate cancer.

One Response

  1. Of course this is quite interesting, but smoking itself is a proxy for a certain acceptance of extra risk in the way one lives. I wonder how much other factors associated with lifestyles of smokers account for the appearance of increased risk. Are there any clues to that?

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