with cancer therapy is going
to become a very serious issue as
more chemotherapy drugs become
available in oral formulations, according
to Deborah Boyle, RN, MSN,
"The growth of oral chemotherapy
is expansive," said Ms. Boyle, a practice
outcomes nurse specialist with
Banner Good Samaritan Regional
Medical Center, Phoenix, Arizona.
"I had an 'aha!' moment when discussing
a patient with a radiation oncology
colleague who specialized in
breast cancer, when she posed the
question, 'Has anyone ever thought of
all the women who took adjuvant
tamoxifen-how do we know they
took their pills as prescribed?"'
A recent investigation that addressed
this issue (J Clin Oncol 21:602-
606, 2003) found that the mean level
of adherence to tamoxifen was actually
somewhat higher than for other
medications; however, nearly 25% of
patients were at risk for inadequate
clinical response resulting from poor
Overall adherence had fallen to
about 50% in year 4 of tamoxifen therapy
in this study, which was based on
a review of prescription records for
about 2,400 women enrolled in New
Jersey Medicaid or pharmaceuticalassistance
"We are making all these assumptions
about how to base our treatment
decisions, prognosis, and further therapy,
and we don't even know if those
patients took their pills the way they
should have," Ms. Boyle said. "This is
a huge issue with overwhelming significance
in the future."
The literature contains little guid-ance for clinicians on the issue of medication
adherence specifically in elderly
cancer patients, Ms. Boyle said (J
Natl Cancer Inst 94:652-661, 2002).
However, some studies of medication
adherence do suggest that when an
older person takes four or more drugs
routinely, the clinician should assume
that at least one of them is not being
taken as directed.
The extent to which patients misunderstand
medication use can be significant.
Ms. Boyle shared one anecdote
regarding a home-care nurse whoasked an elderly patient about a large
bowl of prescription pills on his dining
room table. The elderly man explained
that the bowl contained all his
medications for the day; every time he
walked through the dining room, he
would grab a handful and take them.
"All he knew was these pills have to
get in this body over a 24-hour period,"
Ms. Boyle said. "He could see no
problem with his way of dealing with
that ongoing demand."
Two or More Medications
In general, the elderly take two
medications daily, most commonly
cardiovascular, analgesic, or central
nervous system drugs, according to
data presented by Ms. Boyle (J Am
Geriatr Soc 50:26-34, 2002). The highest
prevalence of medication use is
among women over 65 years of age;
23% take at least five prescription drugs
daily, and 12% take 10 drugs daily.
Implications of nonadherence incancer can be serious. For example, a
nonadherent patient's condition could
worsen as a result of inadequate drug
consumption. As a consequence, that
patient might then have to undergo
unnecessary diagnostic testing and
even hospitalization. Additionally,
changes in the dose or regimen might
be made unnecessarily.
Problems of Nonadherence
Cancer patients who are nonadherent
may require more doctor visits,
more hospitalizations, and longer
lengths of stay when they are hospitalized.
The value of clinical trials may
suffer, as well: nonadherence could
lead to misleading results, inconsistent
response rates, and potentially
erroneous dosing recommendations.
"There are a myriad of problems
that need to be identified," Ms. Boyle
- What risk factors are associated
- How do cost, anxiety, and memory
and hearing impairments affect
- What strategies improve adherence?
Ongoing education? Written reminders?
Phone follow-up? Memoryenhancing
Medication logs and diaries can
help with surveillance of adherence,
Ms. Boyle said. Having patients bring
in their medications for review can
also foster clarification and address
inaccurate practices. This practice may
also reveal the patient's use of herbal
"The most profound take-home
message in all of this is that cancer
health care providers should expect
problems with adherence," she added.
"The appropriate and prescribed regimen
of drug consumption should
never be assumed."