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Biomarkers The benefit of genetic testing for breast cancer remains questionable
Every year around 70,000 women in Germany develop breast cancer. For those who are undergoing surgery, the following question usually arises as to whether chemotherapy is necessary. To answer this, biomarker tests are supposed to help. But scientists now report that these gene tests are not clear.
No clear knowledge gain
More than 70,000 women in Germany suffer from breast cancer each year. Many of them have to undergo chemotherapy with stressful side effects. But for a long time, health experts have pointed out that breast cancer does not always make sense. In fact, biomarker testing should help in deciding if chemotherapy is needed after breast cancer surgery. However, scientists now report that the gene tests used in certain breast cancer patients do not bring any clear knowledge gain in the decision for or against chemotherapy.
Genetic tests should help to find out whether it makes sense to perform chemotherapy after a breast cancer operation. But these tests bring no clear insight, according to new research. (Image: WavebreakMediaMicro / fotolia.com) Metastases often occur late
There can be no talk of a clear benefit of the tested test. On the one hand, the observation period of five years is too short, because many metastases occur only 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 the cancer due to a chemotherapy waiver 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
About 80 percent of breast cancer patients in Germany will never suffer recurrence, according to the current judgment, according to the IQWiG. Roughly estimated in 20,000 patients, it is uncertain whether they benefit from chemotherapy.
The institute was to investigate the benefits of using biomarkers for the treatment decision of women, for whom it is still unclear whether they would ever experience a recurrence of the disease (relapse) or whether their cancer would respond to the chemotherapy.
"If that's not the case, chemotherapy is an unnecessary burden," the experts write.
Advantages and disadvantages of chemotherapy waiver
While initial findings from MINDACT indicate that the benefits and disadvantages of chemotherapy waiver are not yet well-founded due to low biomarker risk levels, "the results we have now are the best we can work with. It is good that this large and carefully planned study was carried out, "said Stefan Lange, Deputy Director of the IQWiG.
He continued, "Among the more than 70,000 women diagnosed with breast cancer in Germany in one year, roughly 20,000 are unclear whether they will benefit from chemotherapy. MINDACT provides important figures to these women and their physicians to thoroughly discuss the advantages and disadvantages of chemotherapy and the limited validity of biomarker testing. "
Differences are too small
According to the authors, the authors of the study found that with chemotherapy 95.9 percent of women were distant metastasis free 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 with the affected women and professionals," said the scientist.
"In debates, for example, on the introduction of colon cancer or prostate cancer screening already putative increases in survival rates by a fraction of a percent as essential goals to be fielded. And here it should be insignificant, if of the approximately 10,000 women a year, who could renounce according to the manufacturer, thanks to the new tests for chemotherapy, die up to 260 more? "
Vague statements about disadvantages of chemotherapy
"Unfortunately, most statements about the disadvantages of chemotherapy are rather vague," said Daniel Fleer of the Non-Drug Procedures Unit, which oversaw the biomarker report at IQWiG.
"It is said again and again that an estimated two to three percent of chemotherapy leads to severe damage, such as permanent damage to internal organs such as the heart or kidney, to death."
However, claims without evidence would often be put into the room. "Thanks to MINDACT, the affected women are now much better aware than before about the risks of not using chemotherapy. However, no information is given on the decision-relevant side effects. So what lies in the other pan, remains unclear for the time being, "said Fleer.
The IQWiG summarizes in its communication: "At present, it is not possible to advise a woman with a clinically high and genetically low risk of a chemotherapy with a clear conscience. The actual "added value" of the biomarker tests for those affected can not be assessed until further results of the ongoing studies are available. "(Ad)