Is the Guidelines for Breast Cancer Genetic Testing Out of Date? - TobiVibes


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Is the Guidelines for Breast Cancer Genetic Testing Out of Date?

In a new study, researchers say more women should be tested for breast cancer genes. However, not everyone is so sure.

Inheriting certain genetic mutations from your mother or father can raise your risk of breast or ovarian cancer.

Knowing you have this type of mutation allows you to take preventive measures as well as help guide screening and treatment.

In the United States, more than 300,000 people receive a breast cancer diagnosis every year. Heredity is involved about 10 percent of the time.

But some women have no idea they’re at increased risk.

They haven’t been tested because they don’t meet current testing guidelines.

In fact, researchers in a new study published in the Journal of Clinical Oncology say guidelines for who should get tested are out of date and should be changed.

What the study found

The National Comprehensive Cancer Network (NCCN) testing guidelines were developed 20 years ago to identify carriers of the BRCA1 and BRCA2 genetic variants.

Over the years, changes have been made in who should be tested and currently include BRCA1/2TP53, and PTEN.

The researchers evaluated current guidelines to identify patients with breast cancer with pathogenic variants in expanded panel testing.

The multi-center prospective registry included community and academic sites with experience in genetic testing for cancer.

Patients included women 18 to 90 years old who had new or previous diagnoses of breast cancer. None had genetic testing before.

Of 959 women, almost 50 percent met NCCN criteria.

All were given an 80-gene panel test.

Overall, slightly less than 9 percent had a pathogenic/likely pathogenic (P/LP) variant.

Among those who met NCCN guidelines, slightly more than 9 percent had a P/LP variant. For those who didn’t meet the guidelines, almost 8 percent had a P/LP variant.

The difference in positive results between these groups wasn’t statistically significant.

The researchers say almost half of women with a P/LP variant are missed under current guidelines.

How This Relates To Guidelines

Dr. Banu Arun is professor in the department of breast medical oncology at the Division of Cancer Medicine at The University of Texas MD Anderson Cancer Center.

She told Healthline that the current guidelines for breast and ovarian cancer were developed for BRCA1and BRCA2 mutations and are quite accurate.

“The study showed that if you fit the criteria for BRCA tests, you’re most likely positive. If you don’t fit, the positive rate is low,” said Arun.

Study authors suggest that all women should get expanded testing, but Arun finds that hard to say based on this paper.

“They tested for other genes and did find a number of patients who were positive for other genes. But they did not report on the family history of these patients. Maybe with evaluation, they would have been tested for those genes,” she said.

“They found a high rate of variants of uncertain significance,” she continued.

Arun explained that we don’t yet know what impact that knowledge has in terms of screening and risk reduction.

“Other studies should confirm whether the positive rate is high in everyone or some of these people had a significant family history of other cancers. Other studies looking at guidelines plus family history as a component might be very helpful,” said Arun.

How Can Tests Be Used

What does genetic testing have to do with prevention and treatment?

“It’s a big deal and it depends on the gene,” said Brown.

Each mutation has a specific window of risk and a lot depends on your age.

According to Brown, a 35-year-old-woman with BRCA-associated breast cancer has a 50 percent risk of developing a second primary cancer in her lifetime. And she has a lot of life ahead of her.

For a 70-year-old, the risk is about 15 percent.

That’s why someone younger might choose a bilateral mastectomy instead of lumpectomy with radiation. Doing so can reduce their lifetime chance of a second primary breast cancer.

It can also affect other forms of treatment.

“Knowing the genetic mutation tells about the behavior of the cancer and the possibility of treatment with targeted therapies,” said Brown.

But it’s important to interpret the results correctly.

Genetic testing can get complicated.

“The more genes you analyze, the more likely you are to identify a variance of unknown significance. It’s difficult to explain the meaning of some genetic variations to the patient. If a patient is concerned about one of these, it might be something they give value to that we would hope they wouldn’t. Gray areas are disconcerting,”

she explained.

And you can’t necessarily define all the consequences in an individual.

“Genes behave in concert with other genes in a unique environment in your body. What you inherit and your lifestyle change how risk might manifest. It’s hard to base testing guidelines on so much random

 

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