Smoking May Interfere with Radiation Treatment for Prostate Cancer

By Eva Kiesler and Jim Stallard,

Monday, February 2, 2015

Pictured: Michael Zelefsky

Researchers call for intensified efforts to help men with prostate cancer quit smoking after a recent MSK study revealed that patients who smoke during radiation therapy face a higher risk of both having the disease return and dying from it.

Smoking not only compromises general health — it can also undermine the effects of cancer treatment. That’s the key finding of a Memorial Sloan Kettering study published last week in the medical journal BJU International.

The researchers analyzed patients who had been treated with external beam radiation therapy for localized prostate cancer (cancer that has not spread from the prostate gland to other body parts). Patients who were smokers had a significantly higher risk of experiencing rising levels of prostate specific antigen, or PSA, in their blood — which suggests the cancer may be returning — and of dying from the disease. Smokers also had a greater likelihood of experiencing side effects related to radiation therapy, such as urinary toxicity, compared with nonsmokers.

Radiation oncologist Michael Zelefsky, the study’s lead author, and his team studied a group of 2,156 MSK patients who received external beam radiation therapy (EBRT) for prostate cancer from 1988 to 2005 and whose smoking history was recorded. The patients were grouped based on whether they were current or former smokers or nonsmokers.

The researchers determined how frequently patients in the different groups developed biochemical relapse — rising PSA — ten years after starting EBRT. On average, they found that current smokers were 1.4 times more likely to develop biochemical relapse than nonsmokers, while former smokers were not at increased risk.

For the same ten-year period following EBRT, current smokers were also at 2.3 times higher risk than nonsmokers of developing distant metastases — cancer that has spread from the original tumor — and of dying from prostate cancer. These risks were much lower for former smokers.

In addition, the study showed that both current and former smokers were at greater risk for developing a number of side effects of the radiation treatment, including complications that impair urinary function, over ten years.

Dr. Zelefsky thinks the increased risk for smokers could possibly be explained by the fact that smoking reduces oxygen concentration within the treated tumors. “This is known to lead to less sensitivity of the cells being killed off by the radiation treatments,” he says.

Healthcare providers are in a position to effectively address tobacco habits.
Michael Zelefsky MSK radiation oncologist

Regardless of the cause, quitting smoking is the best way to avoid these negative effects.

“Healthcare providers are in a position to address tobacco habits effectively as part of clinical care,” Dr. Zelefsky says, adding that they must renew efforts to help prostate cancer patients to stop using tobacco in light of the study’s findings.

These efforts apply to other cancers as well. MSK and Massachusetts General Hospital have jointly launched a program to bolster smoking cessation in cancer care. The intervention includes both FDA-approved smoking-cessation medications and additional counseling.

The National Cancer Institute has also called for reforms to enhance the quality of care of tobacco-dependent cancer patients. The recommended changes include a uniform approach for assessing smoking status, refining electronic medical records and clinical trials to identify and target smokers, and evaluating ways to overcome barriers to quitting.


Yet again, another negative consequence of smoking...the list is so lengthy, and at what point will smokers finally listen?

What if the cancer patient smokes marijuana is that the same thing?

Thank you for your comment. We consulted with Dr. Zelefsky about your question and he responded: "This is an interesting question but we don't have information at the present time to answer this point."

What about non-tobacco smoking such as vaping (e-cigs) with no nicotine added or herbal cigarettes?

Dear Bob, we sent your comment to Dr. Zelefsky, who led the research described in the blog post, and he said: “It is difficult to answer that question based upon the research we have done. Our study was limited to tobacco-based smoking.”

For more information about the safety of electronic cigarettes, you may be interested in reading another post on our blog:… or the FAQ in the Patient Education section of our website:….

Thank you for reaching out to us.

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