The likelihood that a woman will take pills to keep her breast cancer from coming back is higher if she tended to consistently take medications as directed in the past, a new study found.

A major problem in medicine in general is when people don't take their medication as prescribed, said lead author Dr. Alfred Neugut, of Columbia University Medical Center in New York City.

"It's kind of well known, but not generally spoken about," he told Reuters Health.

The problem, known as nonadherence, also extends to cancer medicines, even though they are generally viewed as life-saving or life-prolonging, he and his colleagues write in JAMA Oncology.

They add that 30 to 50 percent of women in previous studies prematurely discontinued hormone therapy, which blocks the hormone estrogen from reaching the cancer and helping it grow.

To see if past behavior could predict women's adherence to hormone therapy, the researchers used insurance data from 21,255 women diagnosed between 2010 and 2012 with breast cancer that had not spread to other parts of the body. The women had all filled at least two prescriptions for hormone therapy.

Sixty-three percent had previously been prescribed at least one medication for high blood pressure, excess fats in the blood, acid reflux, thyroid problems, diabetes or thinning bones.

Based on when the women refilled their prescriptions, about 16 percent appeared to be nonadherent to their hormone therapy.

Among women who had taken as directed at least one medication for a chronic condition, about one in 10 didn't stick to their hormone therapy. By comparison, about one in five women who had never been prescribed drugs for a chronic condition were non-adherent to their hormone therapy, as were nearly one in four women who had not adhered to past chronic condition prescriptions.

"If you were nonadherent to your hypertension or other pills, you were likely to be nonadherent with your (hormone therapy) pills and vice versa," Neugut said.

High out-of-pocket costs and a high number of other health problems were also tied to an increased likelihood of nonadherence to hormone therapy.

"Whatever trait it is in you, whatever your personal quirk is that makes you obsessive compulsive or sloppy about your pill taking, that holds true for your chronic disease pills or oncology pills," Neugut said.

The results can't be generalized to everyone since nearly all the participants had insurance, the researchers write. Additionally, the authors lacked information on other factors that may have influenced adherence.

Neugut is working now to see if text reminders may increase adherence to hormone therapy, but those results won't be published for several months.

The new study helps identify women who should be targeted with interventions to increase adherence, he said.

SOURCE: http://bit.ly/1UG3rHZ JAMA Oncology, online June 8, 2016.