Latest findings indicate one- and two-year study results not as predictive as longer-term studies
ROCHESTER, Minn. -- In their efforts to explore more effective and efficient ways to conduct clinical trials, Mayo Clinic cancer researchers will present new recommendations about how long studies should track results when evaluating new cancer therapies. An analysis led by Daniel Sargent, Ph.D., director of statistics for Mayo Clinic Cancer Center, shows that many study results garnered after three years are just as reliable as those produced after five years. But, data provided after two years of study are less precise, and those provided after only one year are not sufficiently reliable.
Dr. Sargent will present these results on May 17, during the 2005 American Society of Clinical Oncology (ASCO) Annual Meeting in Orlando, Fla. Dr. Sargent is one of the founders of the Adjuvant Colon Cancer Endpoints (ACCENT) Group that is studying whether there are ways to make results of clinical trials in oncology available more quickly, to provide effective treatments to patients faster.
"We found last year that outcomes after three years were highly predictive of the five-year outcomes, so we went back and asked 'could we look after one year or two years,' " says Dr. Sargent. "Our new results suggest that two years is almost as good as three years, but that one year is too early."
Last year, Dr. Sargent presented his results on colon cancer therapies to the Food and Drug Administration (FDA), which agreed with his conclusions, and allowed three years of follow-up study to be part of the evidence in considering new drug therapies for colon cancer treatment. In the past, five years of follow-up had been required before results were considered definitive.
The recommendations from the study presented at the 2005 ASCO conference were based on the study of individual patient data from 20,898 patients and 18 randomized trials.
ACCENT is an international collaboration involving researchers throughout Europe, Canada and the United States. Dr. Sargent helped found the group about a year and a half ago to focus efforts on studies involving colon cancer. As ACCENT continues its work, it may broaden its focus to include other cancers, he said.
"We were dissatisfied with how long it takes to complete trials and make promising new therapies available to help patients," says Dr. Sargent. "Our goal was to see if there was a better and more efficient way to conduct the trials."
Dr. Sargent says the research is not perfect, and some therapies yield different results at three years than they do at five years. "We are committed to following patients for long-term outcomes, and if the results change with this further follow-up, we could modify treatment," he says. "The long-term health of the patient is still the ultimate goal."
DISCLOSURE: This study was funded by the National Cancer Institute (NCI) and coordinated by the North Central Cancer Treatment Group (NCCTG), a national clinical research group sponsored by the NCI. NCCTG is a network of more than 400 community-based cancer treatment clinics in the United States, Canada and Mexico that work with Mayo Clinic to conduct clinical studies for advancing cancer treatment.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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