A sizeable minority of patients diagnosed with lung and colorectal cancer continued smoking after their diagnosis, according to a recent Harvard Medical School study published in the journal Cancer.

Though the percentage of smokers universally decreased in that time period, the study—headed by Harvard Medical School Associate Professor of Psychology Elyse R. Park—found a disparity in the number of those quitting between the two types of cancer.

“The proportion of smokers that quit was actually lower among colorectal cancer patients, and in that case I think it’s probably because they don’t perceive their cancer as being related to smoking,” said HMS Associate Professor of Health Care Policy Nancy L. Keating, also a researcher on the study.

The researchers analyzed a sample of over 5,000 lung and colorectal cancer patients and compared the percentage of patients who were smoking at the time of diagnosis with the number still smoking five months later.

HMS Health Care Policy Assistant Professor Yulei He, who was not involved in the research,  did not express surprise at the study’s findings. He said that patients who are diagnosed with something as traumatizing as cancer may not have the willpower to quit smoking or, if their treatments are effective, even feel the need to do so.

Further, Park said that the “embarrassment and stigma” of being diagnosed with cancer as a smoker may further deter patients from quitting.

“It’s a time when many feel very helpless,” Park said.

The study’s findings also raise questions about the role that medical professionals play in helping their patients overcome smoking addictions.

“I think physicians in general probably need more training in effective motivational techniques to help get their patients to quit,” Keating said. “The challenges of taking care of patients with 15-minute visits [do] make spending a lot of time thinking and talking about smoking cessation very challenging.”

Despite the difficulties associated with getting smokers to quit, Keating said there is hope for greater success in the future. For example, other health professionals could provide physicians with more training in counseling patients on smoking cessation.

Yet ultimately the percentage of cancer patients who cut the habit will only increase if they are motivated enough to make a change, according to Keating.

“I just think it’s never too late to do something to help yourself,” Park said.