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Breast Cancer Patients May Overestimate the Benefits of Adjuvant Chemotherapy

Breast Cancer Patients May Overestimate the Benefits of Adjuvant Chemotherapy

SAN ANTONIO—Most 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 chemotherapy.

"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."

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