Breast Cancer Patients May Overestimate the Benefits of Adjuvant Chemotherapy

SAN ANTONIO—Most breast cancer patients vastly overestimate the benefitsof adjuvant chemotherapy, believing that it reduces their risk of recurrenceby as much as 77%, Laura Siminoff, PhD, reported at a general session ofthe San Antonio Breast Cancer Symposium.

It is important for informed consent that women understand the truerisk-to-benefit ratio of adjuvant treatment, she said. The benefits ofadjuvant chemotherapy are real but modest, she pointed out, and many womenwith a very low risk of recurrence are now receiving such therapy routinely.

Dr. Siminoff presented the results of a survey of 317 breast cancerpatients who had received adjuvant chemotherapy. All were members of theNational Alliance of Breast Cancer Organizations (NABCO); most were whiteand 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 werewell informed about the initial status of their breast cancer. "Theyknew 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 informationabout their prognosis, and even less, 27%, recalled being provided witha quantitative estimate of their prognosis both with and without adjuvantchemotherapy.

"Interestingly," Dr. Siminoff said, "the lack of quantitativeinformation did not stop these women from making such estimates for themselves;70% provided us with estimates of what they believed was their risk ofrelapse at five years both with and without their actual therapy."The women's mean estimate of proportional risk reduction with adjuvanttherapy was "a staggering 77%."

The researchers also looked at a subset of patients who had stage Idisease at diagnosis and thus had the lowest risk-to-benefit ratio foradjuvant treatment. "Again, these patients substantially overestimatedthe effects of adjuvant therapy," she said. "Their median estimateof their proportional risk reduction was 70%."

Small Benefits Important

Would these women still have wanted adjuvant therapy if they had receivedan accurate estimate of their prognosis and the effectiveness of such treatment?To answer that question, the women were asked to indicate what amount ofnet benefit from adjuvant treatment they would find acceptable.

"Women on average indicated a willingness to accept a surprisinglylow amount of risk reduction," Dr. Siminoff said. "A median improvementof only 1% would have been acceptable; however, there was substantial variationbetween women, and a substantial minority wanted to receive much higherdegrees of benefit."

In addition to raising concerns about informed decision-making, particularlyamong patients with low-risk, node-negative tumors, the survey resultsare important, Dr. Siminoff believes, because of the current rush to writetreatment guidelines, often without input from consumers or empirical studiesof patient preferences.

Such guidelines may omit adjuvant treatment when the survival benefitis small, but, she said, for some women, such small benefits may be important.

"We believe that guidelines should not be substituted for informeddecision-making," she said, "or be used to supersede individualizedpatient care or patients' input about their values and preferences."