Fewer than half of nearly 8,000 women with early-stage breast cancer completed their full regimen of hormone therapy according to the prescribed schedule, a new study has found.
Investigators found that younger women were particularly likely to discontinue treatment. The findings underscore the need to both better understand the reasons behind such treatment non-compliance and also develop interventions to reduce it.
"We were surprised to see that so many young women stopped treatment early, despite the fact that the therapy has a proven track record of reducing breast cancer recurrence," said Dawn Hershman, MD, associate professor of medicine and epidemiology at Columbia University Medical Center, who led the study. "Perhaps we need to do a better job of making patients aware that to get the full benefit of treatment, they need to take their medications on time and for the full duration."
The researchers found that women under age 40 had the highest risk of discontinuing therapy early. By 4.5 years, 32 percent of all patients in the study had stopped taking their hormone therapy, and of those who did not stop, only 72 percent finished on schedule (meaning they took their medication more than 80 percent of the time).
They found that in women younger than 40 and older than 75, those who had lumpectomy as opposed to mastectomy and those with other medical illnesses were more likely to discontinue hormonal therapy early. Asian/Pacific Islander ethnicity, a history of prior chemotherapy, being married and longer prescription refill intervals were associated with completing 4.5 years of hormonal therapy. Longer refill intervals meant fewer chances to not refill prescriptions.
"Physicians are often unaware of patient compliance, and this is becoming an increasingly important issue in cancer," Dr. Hershman said. "It's very disturbing that patients under 40 had the highest discontinuation and non-adherence rates, because those patients have the longest life expectancy. If we can better understand the issues surrounding compliance with hormonal therapy, this might help us understand why patients don't adhere to other treatments that are moving out of the clinic and into the home, such as oral chemotherapy, as often as we would like."
She added that there are several possible reasons for halting therapy early, noting that 13 percent of the women delayed getting their first prescription refilled. These factors can include the side effects of the therapy, such as joint pain, hot flashes or fatigue, a lack of understanding of the benefit of the therapy, and high costs of medications and/or insurance co-payments.
Jennifer Obel, MD, member of ASCO's Cancer Communications Committee
"This new study reaffirms some worrisome trends for women completing hormonal therapy, and brings up the larger issue of non-compliance for cancer therapies in general. As we increasingly move treatments out of the clinic and into the home - we now have more than 50 oral chemotherapy medications - compliance has become a significant problem that hasn't been addressed very well. Patients tend to underestimate side effects and under-report events that happen between clinic visits. We need to identify reasons why patients don't take their drugs before we can find ways to reverse this trend."