New technology may help women with breast cancer forego chemotherapy

For women who are diagnosed with breast cancer every year in the U.S., a leading cause of cancer death among Hispanic women, one of the toughest choices to make is what type of treatment to choose.

A new test, called MammaPrint, is making it possible so women could forego chemotherapy.

Such was the case for 46-year-old Zaida Vazquez when she was diagnosed with breast cancer this May. Breast cancer is the most commonly diagnosed cancer. Among Hispanic women, breast cancer will be the leading cause of cancer death this year (16 percent), followed by cancers of the lung (13 percent) and colorectum (9 percent), according to the American Cancer Society.

Vasquez had surgery in July and then opted for chemotherapy – but stopped midway because she said it made her feel terrible. Her days were ridden with nausea and exhaustion. That was when her oncologist, Dr. Mayra Rivera, suggested forgoing chemotherapy based on her MammaPrint results that analyzed 70 genes associated with a breast tumor’s chance of metastasizing.

“MammaPrint gives me a biology footprint of the tumor,” said Dr. Rivera of Puerto Rico. “And, with patients like Zaida in the early stages of their breast cancer, also known as low risk, this test would benefit more women like her.”

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MammaPrint is among a growing number of tests attracting interest in the medical world because it lets women know if they could avoid chemotherapy with little risk that they’ll relapse. The tests examine a woman’s genes to determine whether the cancer has a chance of spreading.

The tests and MammaPrint gained stature last month when a study exploring its effectiveness was published in The New England Journal of Medicine. MammaPrint was used in the study, called MINDACT, which analyzed 6,693 breast cancer patients across 112 centers in Europe with newly diagnosed early-stage breast cancer.

J. Leonard Lichtenfeld, deputy chief medical officer for the American Cancer Society, said these types of tests are not new.

Lichtenfeld said that in the late 90s, there was a substantial amount of tests being developed that looked into the tumor tissue to predict how it would behave over time. Similar to MammaPrint’s approach was Oncotype DX, which took off but only analyzed 21 genes. MammaPrint looks into the activity of 70 genes.

MammaPrint is lesser known and used less often, but has become more popular the past few years.

Still, it’s stirred discussion in the medical community because the tests are not 100 percent accurate and could falsely tell a woman she doesn’t need chemotherapy when she actually does. Others, however, believe it will spare thousands of women with early-stage breast cancer the painful – and expensive – experience of going through chemotherapy.

The Journal of Medicine article said the MammaPrint clinical trial offers probabilities and not necessarily concrete guidance.

“The reality is that there haven’t been real life trials over an extended period of time to show that these tests work the way they are supposed to work,” Lichtenfeld said.

The first author of the MINDACT study said it’s worth noting that this is the first clinical trial of its kind.

“There hasn’t been another clinical trial wherein diagnostic tests were evaluated like this, that looked into the biology of the disease, for as long as we did,” said Dr. Laura van ’t Veer, chief research officer of the study.

Of the European countries involved in the study, Spain was one of the most active in the trial coming in at about 700 participants. In centers in Barcelona and Madrid, MammaPrint is already being used frequently.

“Everyone can agree that avoiding chemotherapy is the end goal but one thing to look at is tumor tissue and the history of a woman and the treatment she got but it’s quite another thing to use forward-looking studies to try to determine the accuracy,” Lichtenfeld added.

Rivera says the new test offers more options to breast cancer patients at low risk who might be hesitant to undergo chemotherapy.

“We are moving toward finding out more about tumors in breast cancers that will help patients make a decision more objectively about next steps,” Rivera said.

Vazquez says she doesn’t regret her decision even if at first her family was on the fence. But after finding out she was at low risk post-surgery, she’s thankful there was another medical option.