No need for chemo in many breast and lung cancers, major studies show

Two major studies released today show that many people with breast and lung cancers may forgo chemotherapy and still live longer, signaling a waning need for what was long seen as the standard of cancer care.

The findings were released at the American Society of Clinical Oncology (ASCO) meeting in Chicago, the world's largest annual cancer conference.

The first study, described as the largest breast cancer treatment trial to date, found that the majority of women with a common form of breast cancer may be able to skip chemotherapy and its toxic, and often debilitating, side effects after surgery depending on their score on a genetic test.

As many as 65,000 women in the United States alone could be affected by the findings.

Until now, women have faced considerable uncertainty about whether to add chemo to hormone therapy after a diagnosis with hormone-receptor positive, HER-2 negative breast cancer when found at an early stage, before it has spread to the lymph nodes.

"With results of this groundbreaking study, we now can safely avoid chemotherapy in about 70 percent of patients who are diagnosed with the most common form of breast cancer," said co-author Kathy Albain, an oncologist at Loyola Medicine in a Chicago suburb.

A 21-gene test called Oncotype DX, available since 2004, has helped guide some decisions on proper care after surgery.

A high recurrence score, above 25, means chemo is advised to ward off a recurrence, while a low score, below 10, means it is not.

The current study focused on those whose scores were in the middle range, from 11 to 25.

More than 10,000 women, aged 18 to 75, were randomly assigned to receive chemotherapy followed by hormone therapy, or hormone therapy alone. Researchers studied their outcomes, including whether or not cancer recurred, and their overall survival.

"For the entire study population with gene test scores between 11 and 25 -- and especially among women aged 50 to 75 -- there was no significant difference between the chemotherapy and no chemotherapy groups," said the findings, published in the New England Journal of Medicine.

The results show that all women over 50 with a recurrence score of 0 to 25 can be spared chemotherapy and its toxic side effects.

For women under 50 with a score of 0 to 15, chemo can be skipped. However, among younger women with scores 16 to 25, outcomes were slightly better in the chemotherapy group, so in those cases doctors may urge patients to consider a chemo regimen.

The results "should have a huge impact on doctors and patients," Albain said.

"We are de-escalating toxic therapy."