Biomarker Tests Benefit Certain Cancer Patients

The benefit of biomarker tests has been reinvestigated to support the decision for or against adjuvant systemic chemotherapy in certain breast cancer patients, that is, women with primary hormone receptor-positive, HER2/neu-negative breast cancer and 0 to 3 affected lymph nodes.

The available biomarker tests aim to assess whether a woman would develop recurrences if she omitted chemotherapy in addition to hormonal therapy, i.e. if her breast cancer would return. Each test analyses the expression of a different group of genes. It is therefore possible that some tests are better at predicting the risk of recurrence than a clinician, who looks at factors such as tumor size and type of tumor tissue, whereas other tests are not.

Scientists at the German Institute for Quality and Efficiency in Health Care (IQWIG, Köln, Germany) investigated the TAILORx study which questioned whether, in women with intermediate Oncotype (Genomic Health, Redwood City, CA, USA) risk score (11 to 25), recurrences were notably more frequent without additional chemotherapy than with chemotherapy.

For all participants overall, there were no statistically significant differences. The women’s age apparently made a difference, however: For patients over 50 years of age or after menopause, the number of recurrences was about the same with and without chemotherapy; hence this group benefited from a test-based decision against chemotherapy. In participants under 50 years of age or before menopause, in contrast, chemotherapy had significant advantages.

Women with risk scores below 11 and above 25 were not randomized in the study. Instead, participants with low scores were not to receive chemotherapy, whereas participants with high-risk scores were to receive this kind of treatment. However, plausible assumptions can be made on the basis of further study data and analyses of subgroups with the values of 11 to 15, 16 to 20, and 21 to 25. According to these assumptions, older women with risk scores between 0 and 25, and younger women with risk scores between 0 and 10 without affected lymph nodes can omit chemotherapy without notably increasing their risk of recurrence. Naturally, women for whom the decision for or against chemotherapy is already clear based on other factors are exempt from this recommendation.

Stefan Lange, MD, PhD, deputy director of the IQWIG, said, “A comparison with the other studies reveals two things. First, the disease event rates of about 15% to 17% were substantially higher than in the MINDACT study, for example. This means that notably more women had recurrences. In principle, this could be expected as the observation period of up to nine years was longer than in the study data available so far. We had noted in the final report that it is rather common for breast cancer to return only after many years, which is why five-year data are unsuitable for reliable conclusions. However, it is still remarkable that chemotherapy did not reduce the risk of recurrence at all in older study participants.”

Related Links:
German Institute for Quality and Efficiency in Health Care
Oncotype