Fewer than half of breast cancer
patients adhere to hormonal therapy regimen
A new study of nearly 8,800 women with early-stage breast
cancer found that fewer than half - approximately 49 percent - completed their
full regimen of hormone therapy according to the prescribed schedule. 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, M.D., 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."
While up to five years of oral hormone therapy (such as tamoxifen and aromatase
inhibitors) for hormone-sensitive breast cancers is frequently prescribed to reduce
the risk of cancer recurrence and death, some previous small studies indicated
that only approximately 40 to 60 percent of women finish their recommended course
of therapy. In order to provide a more comprehensive perspective, Dr. Hershman
and her colleagues examined automated pharmacy records of 8,769 women diagnosed
with stage I, II or III, hormone-sensitive breast cancer between 1996 and 2007.
They used the records to identify hormonal therapy prescriptions and refill dates.
Each woman filled at least one prescription for hormonal therapy within one year
of diagnosis. Women used tamoxifen (43 percent), aromatase inhibitors (26 percent)
or both (30 percent).
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.
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