Biomarkers: The benefit of the genetic test for breast cancer remains questionable

Biomarkers: The benefit of the genetic test for breast cancer remains questionable

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After breast cancer surgery for chemotherapy? Genetic testing does not give a clear answer
Every year around 70,000 women in Germany develop breast cancer. For those who undergo surgery, the question then usually arises whether chemotherapy is necessary. To answer this, biomarker tests are supposed to help. But scientists are now reporting that these gene tests do not provide clear insights.

No clear gain in knowledge
Every year, over 70,000 women develop new breast cancer in Germany. Many of them have to undergo chemotherapy with stressful side effects. But health experts have long been pointing out that this is not always useful for breast cancer. Biomarker tests are supposed to help you decide whether chemotherapy is necessary after breast cancer surgery. However, scientists are now reporting that the gene tests used in certain breast cancer patients currently do not provide any clear insight into the decision for or against chemotherapy.

Metastases often occur late
There is no clear benefit from the examined test. On the one hand, the observation period of five years is too short, because many metastases only appear in the following years.

"On the other hand, it is questionable whether one to two percent more deaths due to the recurrence and spread of cancer due to a lack of chemotherapy are really insignificant," reports the Institute for Quality and Efficiency in Health Care (IQWiG) in Cologne in a press release. The scientists had evaluated preliminary results of the so-called MINDACT study.

An unnecessary burden
According to IQWiG, around 80 percent of breast cancer patients in Germany will never again experience a relapse. It is roughly estimated that 20,000 patients cannot be sure whether they will benefit from chemotherapy.

The institute should investigate the use of biomarkers for the treatment decision of women, for whom it is still unclear whether they would experience a recurrence of the disease (relapse) or whether their cancer would respond to chemotherapy.

"If this is not the case, chemotherapy is an unnecessary burden," write the experts.

Advantages and disadvantages of not using chemotherapy
According to the first results of MINDACT, no reliable assessments of the advantages and disadvantages of not using chemotherapy due to low biomarker risk values ​​are yet possible, “but the results now available are the best that we can currently work with. It is good that this large and carefully planned study was carried out, ”said Stefan Lange, Deputy Head of IQWiG.

He went on to say: “The roughly 70,000 women who are diagnosed with breast cancer in Germany in one year are roughly 20,000 who are not sure whether they will benefit from chemotherapy. MINDACT provides these women and their doctors with important figures to thoroughly discuss the advantages and disadvantages of chemotherapy and the limited informative value of biomarker tests. ”

Differences are too small
According to the information provided, the study authors found that 95.9 percent of women with chemotherapy were free of distant metastases after five years and 94.4 percent without chemotherapy.

"According to the authors, the differences are so small that women can be spared chemotherapy," says Lange. "I would like to discuss this more closely with the women and experts concerned," said the scientist.

“In the debates, for example, on the introduction of colon cancer or prostate cancer screening, presumed increases in survival rates by a fraction of a percent are already being raised as absolutely desirable goals. And it should be insignificant here if up to 260 more of the approximately 10,000 women a year who, according to the manufacturer, could do without chemotherapy thanks to the new tests? "

Vague statements about disadvantages of chemotherapy
"Unfortunately, most of the statements about the disadvantages of chemotherapy are rather vague," explained Daniel Fleer from the Non-Medicinal Processes department, who was responsible for the biomarker report at IQWiG.

"You keep reading that an estimated two to three percent of chemotherapy leads to serious damage, such as permanent damage to internal organs such as the heart or kidney, and even death."

However, claims without evidence are often simply put in the room. “Thanks to MINDACT, the women concerned now know much better than before how big the risks of not using chemotherapy are. No information has yet been given on the side effects relevant to the decision. So what's in the other weighing pan remains unclear for the time being, ”says Fleer.

The IQWiG summarizes in its communication: “At present, a woman with a clinically high and genetically low risk cannot be advised against chemotherapy with a clear conscience. The actual "added value" of the biomarker tests for those affected can only be assessed when further results from the ongoing studies are available. "(Ad)

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