Quitting smoking can significantly improve the effectiveness of cancer treatment, according to the U.S. Surgeon General, yet almost half of cancer patients continue to smoke after they've been diagnosed.

A new study from Northwestern Medicine and the Abramson Cancer Center at the University of Pennsylvania found cancer patients have better success quitting and are not as prone to relapsing one year later if they undergo counselling sessions for 24 weeks and take the smoking cessation medication varenicline for 24 weeks, compared to the routine 12 weeks.

"With the stress cancer patients are under, they tend to be at higher risk of relapsing for a longer period of time," said senior author Brian Hitsman, associate professor of preventive medicine at Northwestern University Feinberg School of Medicine. "So we thought providing treatment for longer would be more effective." 

The findings were published in the journal Psycho-Oncology.

Patients in the study had a variety of cancers, ranging from breast to skin to lung cancer.

Forty percent of patients actively had cancer while others had had cancer in the past five years.

For Billie Green, 70, smoking while undergoing cancer treatments was the result of a combination of her 50-year smoking history and the stress of her life-altering lung cancer diagnosis that made it difficult to quit.

"When someone tells you that you have cancer, you get scared," said Green, who lives in Chicago. "Smoking used to be my best friend when I was upset, after I ate. But I knew it didn't make any sense to keep smoking, if I'm going in for treatment all the time."

Green's daughter learned about the Northwestern Medicine smoking cessation study specifically aimed at cancer patients - one of the largest smoking cessation trials ever conducted with cancer patients - and asked her to enrol.

Green did so a month later.

Today, Green is in remission from her cancer.

She still smokes but has dramatically cut back from one pack a day to one cigarette every other day.

Green said the treatment - a combination of medication and behavioural counselling sessions - made her aware of what she was doing to her body.

The higher success of quitting, though was true only for the 43 percent of patients who took varenicline as directed for the full 24 weeks.

For the other 57 percent of participants who did not take the medication as prescribed, there was no significant difference in quit rates or susceptibility of relapsing compared to the control group, who only received varenicline for the first 12 weeks.  

Both groups received the same behavioural therapy - counselling sessions to set quit dates, learn coping skills and manage withdrawal symptoms - over the course of 24 weeks.

Many of the study participants in the control group and experimental group continued with the full counselling regimen, despite not always adhering to the medication regimen.

"While the behavioural therapy wasn't the focus of this study, we will need to study this part more closely because it can be a very powerful tool for cancer patients to quit smoking," Hitsman said. "You can imagine how someone going through a severe or significant disease and treatment process could benefit from the support we provided in this study."

This was only the second study to examine the use of varenicline for cancer patients.

It was the first smoking cessation study - for any population of smokers, not just cancer patients - to double the length of the standard course of 12 weeks of varenicline and include behavioural therapy in the treatment.

Because varenicline treatment had never been given to a cancer population for longer than 12 weeks, the scientists wanted to assess its safety.

The study found taking an additional 12 weeks of the medication did not increase the side effects for patients.

"We hear from cancer patients and oncologists that varenicline may cause serious side effects or that managing the stress of the disease makes addressing tobacco use among patients inappropriate," said first author Dr. Robert Schnoll, associate professor in the department of psychiatry and associate director for population science at the Abramson Cancer Center.

"But the results from this study show that this leading FDA-approved medication is effective for cancer patients, doesn't increase patient risk and yields increased benefits for those who take the medication as prescribed."

"We need now to focus on how we can get more patients who smoke to use the medication and use it sufficiently if we are to see broader population-level gains," Schnoll said.

Source: Northwestern University