SAN ANTONIOMost breast cancer patients vastly overestimate the benefits
of adjuvant chemotherapy, believing that it reduces their risk of recurrence
by as much as 77%, Laura Siminoff, PhD, reported at a general session of
the San Antonio Breast Cancer Symposium.
It is important for informed consent that women understand the true
risk-to-benefit ratio of adjuvant treatment, she said. The benefits of
adjuvant chemotherapy are real but modest, she pointed out, and many women
with a very low risk of recurrence are now receiving such therapy routinely.
Dr. Siminoff presented the results of a survey of 317 breast cancer
patients who had received adjuvant chemotherapy. All were members of the
National Alliance of Breast Cancer Organizations (NABCO); most were white
and college educated. On diagnosis, 83% had stage I or II disease.
The researchers, from the University of Texas Health Science Center,
San Antonio, where principal investigator Peter Ravdin, MD, PhD, is based,
and Case Western Reserve University, found that most of the women were
well informed about the initial status of their breast cancer. "They
knew their node status, tumor size in centimeters, and ER status,"
said Dr. Siminoff, associate professor of medicine at Case Western Reserve.
However, only 45% had been given some form of quantitative information
about their prognosis, and even less, 27%, recalled being provided with
a quantitative estimate of their prognosis both with and without adjuvant
"Interestingly," Dr. Siminoff said, "the lack of quantitative
information did not stop these women from making such estimates for themselves;
70% provided us with estimates of what they believed was their risk of
relapse at five years both with and without their actual therapy."
The women's mean estimate of proportional risk reduction with adjuvant
therapy was "a staggering 77%."
The researchers also looked at a subset of patients who had stage I
disease at diagnosis and thus had the lowest risk-to-benefit ratio for
adjuvant treatment. "Again, these patients substantially overestimated
the effects of adjuvant therapy," she said. "Their median estimate
of their proportional risk reduction was 70%."
Small Benefits Important
Would these women still have wanted adjuvant therapy if they had received
an accurate estimate of their prognosis and the effectiveness of such treatment?
To answer that question, the women were asked to indicate what amount of
net benefit from adjuvant treatment they would find acceptable.
"Women on average indicated a willingness to accept a surprisingly
low amount of risk reduction," Dr. Siminoff said. "A median improvement
of only 1% would have been acceptable; however, there was substantial variation
between women, and a substantial minority wanted to receive much higher
degrees of benefit."
In addition to raising concerns about informed decision-making, particularly
among patients with low-risk, node-negative tumors, the survey results
are important, Dr. Siminoff believes, because of the current rush to write
treatment guidelines, often without input from consumers or empirical studies
of patient preferences.
Such guidelines may omit adjuvant treatment when the survival benefit
is small, but, she said, for some women, such small benefits may be important.
"We believe that guidelines should not be substituted for informed
decision-making," she said, "or be used to supersede individualized
patient care or patients' input about their values and preferences."