The death, from esophageal cancer, of Christopher Hitchens, the brilliant and often controversial writer and journalist, has prompted me to write this blog. In addition to his avowed atheism (described in his best-selling book, God Is Not Great: How Religion Poisons Everything), perhaps the most talked-about aspect of his life was his unabated consumption of cancer-causing tobacco and alcohol throughout the course and treatment of his illness, right up to the last day of his life.

Was Hitchens unique in this regard? Not by a long shot.

According to a recent story in London’s Daily Mail, actor Michael Douglas can’t seem to shake his dependency on tobacco almost a year after being diagnosed and treated for the same type of advanced-stage cancer as Hitchens.

While you might think that a diagnosis of esophageal or lung cancer would be enough to stop smokers and/or drinkers in their tracks, statistics show that up to 25 per cent of them still can’t shake the habit!

Given the high IQs of Hitchens, Douglas, and my late colleague, cancer specialist Dr. Eve Wiltshaw, who died, still smoking, of cigarette-related bladder cancer, intelligence probably has little to do with it. So what does?

Addiction is one major cause. Another is the enabling behaviour of a spouse; Michael Douglas’ wife, actress Catherine Zeta-Jones, also smokes. If the partner continues to practice the same bad habit, it obviously hinders the cancer patient from quitting!

A third factor is the belief that “it is too late to quit”, i.e., once the diagnosis has been made, stopping a bad habit is futile because the damage has already been done. Yet, the facts refute that premise.

For example, in a review of 10 studies, published last year in the British Medical Journal, researchers found that those who stopped smoking after a diagnosis of early-stage lung cancer had a 50 per cent lower risk of recurrence and death than people who continued to smoke; the five year survival rate was 63-70 per cent in those who quit, compared to 29-33 per cent in those who continued to smoke.

Similarly, a 1993 study by Canadian researchers showed that, compared to those who quit smoking, patients with head and neck cancer who continued to smoke during radiation treatment had a significantly lower two-year survival rate.

Yet smoking and drinking cessation are not the only lifestyle change that can have a positive influence on survival after a cancer diagnosis. It is becoming increasingly clear that obesity influences the development and outcome of many different cancers, most notably breast and uterine cancer.

Several large studies suggest that obesity increases the risk that breast cancer will recur despite chemotherapy and radiation treatment following surgery. This finding has led experts to suggest that “weight management should be a part of the strategy to prevent the occurrence, recurrence and death because of breast cancer.”

The take-home message? Lifestyle changes can really make a difference to the outcome of many common cancers. Although it may be difficult, it is never too late to give up tobacco and alcohol, to cut calories and to exercise. As I often tell my patients, “Leave the treatment to the specialists; the rest is up to you.”