Gene Test Can Tell Who Needs Chemo, Who Doesn't

Chemotherapy is "not pretty," a breast cancer survivor tells the AP—so a new study on women with early-stage breast cancer is encouraging, claiming a gene test can parse out patients who may be able to skip chemo because it won't ultimately provide much, if any, benefit. The study in the New England Journal of Medicine showed that patients with breast cancer that hadn't spread to the lymph nodes and who qualified as "low risk" after taking a 21-gene test responded well to just taking hormone-blocking drugs and opting out of chemo, which can come with significant side effects. Per a press release, the patients who only received hormone therapy had a 98% survival rate after five years, with less than a 2% chance the cancer had spread. "We knew these patients were going to do well, but we didn't dream they would do this well," says lead author Joseph Sparano, per the Wall Street Journal.

The trial involved 10,253 women with early-stage breast cancer, per the release. After taking the Oncotype DX gene test—sold by Genomic Health since 2004 and covered by many insurers, per the AP—17% were classified as a high risk for cancer recurrence, 67% as intermediate risk, and 16% as low risk. The high-risk group received chemo and hormone therapy, and the intermediate group hormone therapy by itself or with chemo (results from those two groups aren't out yet). But results for the low-risk group were significant enough to be publicized. A Memorial Sloan Kettering doctor not involved in the study is impressed, telling the AP "there is really no chance that chemotherapy could make [those numbers] better" and that genetic testing could help refocus chemo efforts on high-risk patients who need it instead of making those who don't go through the grueling process. (Chemo doesn't have to translate to baldness, either.)