One of every eight girls born today will develop breast cancer at some point in her life.

Breast tumors are essentially renegade masses of cells that largely ignore the rigid guidelines required for healthy cell growth. Many tumor genes switch on or off at inappropriate times, leading to uncontrollable growth.

In many cases, cancer therapy causes damage nearly as devastating as the disease itself.

Now a new genetic test aims to streamline treatment for early-stage breast cancer, potentially sparing women side effects like fatigue, nausea and hair loss that typically accompany chemotherapy.

Chemotherapy often significantly reduces the risk of recurrence and death due to breast cancer. But recent studies suggest women with less severe forms of the disease may not benefit from the treatment.

Currently, doctors predict who will benefit from chemotherapy by looking at factors like tumor size and grade. But the new genetic test may perform this task with far more precision by determining which genes are turned on or off in the tumors of individual women.

The test is performed on the breast tissue after surgery, and analyzes the expression profile of twenty-one genes in the excised tumor. The information allows doctors to predict the likelihood the cancer will return if the patient is treated with hormonal therapy alone.

And while a cancer diagnosis is never an easy burden to bear, the new test may make treatment for breast cancer more tolerable for some.