Making decisions about breast cancer treatment based on measures of a patient’s general well-being, stress level and ability to enjoy  normal life activities is most effective in clinical trials in which quality of life is the primary outcome, a new Canadian study shows.

Researchers from Laval University in Quebec, Canada reviewed 190 clinical trials of breast cancer treatments and found that quality of life (QOL) measures were most useful for clinical decisions in trials that used non-biomedical interventions such as group therapy.

QOL measures should also be included in clinical trials of metastatic breast cancer treatments when a minimal survival difference is expected or when treatments have substantial differences in toxicity, the researchers said.

In a news release, the researchers said that when quality of life is not the primary endpoint of a clinical trial, "QOL results should ideally appear in a companion article published at the same time as the traditional medical outcomes article so that a full view of the risks and benefits of the intervention can be presented at the same time to clinicians."

The researchers noted that both the World Health Organization and the U.S. Food and Drug Administration stress the importance of patients' quality of life, but that clinical trials sometimes don't include that measure due to the cost of collecting the data.

In an accompanying editorial quoted in the journal news release, Dr. Patricia Ganz of the University of California at Los Angeles commented that the increase in studies considering quality of life "reflects the increased acceptance of the patients' voice in assessing the outcome of [breast cancer treatment] trials."

The study appears online in the Jan. 7 issue of the Journal of the National Cancer Institute.