Chemo yes or no? A genetic test makes the difference
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More about the experts All content is checked by medical journalists.Vomiting, hair loss, organ damage - chemotherapy has a wide range of side effects. The reason: Most cytostatics cannot differentiate between healthy cells and tumor cells. For many cancer patients, chemotherapy is the last resort - but it is obviously not necessary for all those affected: Breast cancer patients with special genetic makeup could possibly do without it.
Who belongs to this group can be determined using the so-called Oncotype DX genetic test: It analyzes a total of 21 genes - 16 cancer genes and five control genes in tumor tissue. A score between zero and 100 is calculated from the result. The following applies: the higher the score, the higher the likelihood of relapse and the less the patient would benefit from chemotherapy.
Upper limit ten points
So far, however, there has been a lack of reliable study data that would confirm the predictive power of the test. Joseph Sparanao of the Albert Einstein College of Medicine in New York and his colleagues have now examined the effectiveness of the procedure in over 10,000 breast cancer patients between 18 and 75 years of age. All participants had hormone receptor-positive, HER2-negative breast cancer. In addition, none of the patients had the tumor spread to the lymph nodes in the armpits.
None of the participants with a maximum of ten points in the Oncotype DX test received no chemotherapy - 16 percent were affected. During the course of their treatment, they only received anti-hormone therapy - mostly with aromatase inhibitors that block estrogen synthesis. Alternatively, tamoxifen was administered, which prevents estrogen from binding to tumor cell receptors.
Low relapse rate
The result: After five years, 98 percent of the patients with an Oncotype DX value of no more than ten were still alive. In addition, 93.8 percent had not formed any new tumors damaging the neighboring tissue and a full 99.3 percent had been spared distant metastases.
"Women with hormone receptor-positive, HER2-negative breast cancer that has not yet spread to the armpit lymph nodes and who have a favorable gene expression profile have very low relapse rates when using only anti-hormone therapy with aromatase inhibitors or tamoxifen," the researchers summarize.
Stop the tumor cells from multiplying
Chemotherapy is the treatment of malignant tumors with so-called cytostatics. These drugs intervene in the growth cycle of cancer cells and thus inhibit tumor growth. Because cancer cells divide very quickly, they are particularly susceptible to cytotoxic drugs. But there is a problem: there are also healthy cell types in the body that multiply quickly - for example those in the mucous membrane or those in the blood-forming bone marrow. Numerous side effects are the result.
Sources:
Sparano J.A. et al .: Prospective Validation of a 21-Gene Expression Assay in Breast Cancer. The New England Journal of Medicine. DOI: 10.1056 / NEJMoa1510764
German Cancer Society, www.krebsgesellschaft.de, accessed on November 12, 2015
Tags: drugs skin organ systems
