Stage 4 Cancer Patients Who Quit Smoking Live an Average of 330 Days Longer Than Smokers

Washington University in St. Louis Study
"Live an Average of 330 Days Longer Than Smokers"

Even patients with stage 3 or 4 cancer can extend their average survival by 330 days if they quit smoking, compared to those who continue to smoke, according to a new study.

A research team led by Professor Li-Shiun Chen at Washington University School of Medicine in St. Louis announced on October 10 (local time) in the Journal of the National Comprehensive Cancer Network that they had confirmed this correlation. The team analyzed the relationship between smoking cessation within six months and mortality within two years among more than 13,000 outpatient cancer patients at a cancer center.

No Smoking sign installed in downtown Seoul. Photo by Jo Yongjun

Previous studies have shown that about 25% of cancer patients in the United States are smokers at the time of diagnosis, and a significant portion of them continue to smoke during treatment. The research team pointed out that this may be due to the misconception that "quitting smoking does not significantly benefit people with cancer, especially those with advanced cancer." They explained that the more advanced the cancer, the greater the benefit of quitting smoking, with survival periods more than doubling in some cases. Therefore, they emphasized that quitting smoking is worthwhile even after cancer treatment has begun.

"Quitting Smoking After Cancer Treatment Begins Is Also Highly Effective"

The research team utilized a smoking cessation program run by Washington University School of Medicine and the Siteman Cancer Center at Barnes-Jewish Hospital, surveying 13,282 cancer outpatients who received care between June and December 2018 about their smoking cessation status within six months, and then tracked and compared their survival rates over the following two years.

Among the subjects, 1,725 (13.0%) were smokers. Of these, 381 patients (22.1%) succeeded in quitting within six months, while 1,344 patients (77.9%) continued to smoke. Within two years, 75 patients (19.7%) in the smoking cessation group and 347 patients (25.8%) in the smoking group had died. When analyzing all cancer types and stages combined, the survival rate two years after the first consultation was 74.7% for the smoking group and 85.1% for the smoking cessation group, indicating that quitting smoking increased the probability of survival by 10.4 percentage points.

The improvement in survival rate was even greater for patients with stage 3 or 4 cancer than for those with stage 1 or 2. Among stage 3 and 4 patients, the point at which 85% had survived was 210 days after the first consultation in the smoking group, but 540 days in the smoking cessation group. The research team explained that for patients with stage 3 or 4 cancer, 85% of those who continued to smoke survived 210 days after their first consultation, whereas 85% of those who quit smoking survived up to 540 days-almost a full year longer.

Dr. Steven Tomashe, the first author of the paper, stated, "For patients with advanced cancer, a year is a long time," adding, "We hope these findings will give them hope and increase their motivation to quit smoking."