The study, published in the New England Journal of Medicine, determined the clinical risk and genomic risk of cancer recurrence for close to 7,000 women with early-stage breast cancer. Clinical risk was determined by features such as tumor size and the number of positive lymph nodes.
Researchers observed outcomes for women with high clinical but low genomic risk of recurrence who did not receive chemotherapy treatments.
Approximately 23 percent of study participants had high clinical risk and low genomic risk. Among such patients that did not receive chemotherapy, the five-year survival rate without distant metastasis (the spread of the cancer) was 94.7 percent. The five-year survival rate without distant metastasis for patients who did receive chemotherapy was just slightly higher by 1.5 percentage points.
Researchers conclude approximately 46 percent of women with breast cancer who are at high clinical risk may not need chemotherapy.
However, an editorial accompanying the article written by researches from Memorial Sloan Kettering Cancer Center in New York City said the study was not large enough to statistically uphold the percentage difference, according to The New York Times.
More articles on genomics:
University of Michigan School of Public Health joins Precision Medicine Initiative
Allscripts subsidiary launches genomics initiative at NIH
Stanford to use Google Genomics storage in precision medicine research
