Recent data confirm the value of using the gene expression of 21 test (Oncotype DX, Genomic Health) to guide the use of adjuvant chemotherapy for early breast cancer.
New results have been obtained as a result of a secondary analysis, which was attended by more than 10,000 women with early breast cancer.
The main results of this study reported last year showed that the test can detect a large group of women (about 70%) that can skip chemotherapy.
In women with hormone receptor, HER2-negative breast cancer patients who have had a high rate of recurrence 21 gene from 26 to 100, and plus adjuvant chemotherapy endocrine therapy, not the estimated frequency of occurrence of cancer was 93% within 5 years.
According TAILORx authors, the result of "better than expected" in this group of women who received endocrine therapy alone (79% at 5 years). A team led by Joseph Sparano, MD, deputy director of clinical research at Cancer Center of Albert Einstein and Montefiore Health System in New York, as well as vice-chairman of the ECOG-ACRIN Cancer Research Group.
This secondary analysis of a "good proof that chemotherapy is justified in recurrence, because it improves the prognosis," Charles Shapiro, MD, Ph.D., Director, Research Center for breast cancer research and cancer survival, Institute of Tisha cancer at Mount sinai in New York City.
The study TAILORx included 10,273 women with hormone-sensitive, HER2-negative breast cancer by more than 1,100 cities in the US, Australia, Canada, Ireland, New Zealand and Peru. Tumor patients were analyzed using gene expression test 21 and the assigned risk evaluation (on a scale from 0 to 100) for cancer recurrence.
The results showed that about 70% of patients with an average recurrence can be spared chemotherapy. The study showed no difference in disease-free survival, regardless of whether the women received only endocrine therapy, or a combination of endocrine therapy with chemotherapy, as reported by Medscape Medical News at the time.
A secondary analysis was focused on the 1389 women in TAILORx, who had a relapse in high risk range (26 and above), which underwent chemotherapy in addition to endocrine therapy after surgery.
Most patients (84%) was obtained chemotherapy regimens containing the taxane and / or anthracycline. The most common treatment schemes were docetaxel / cyclophosphamide (42%) anthracycline without taxane (24%) anthracycline and a taxane (18%), cyclophosphamide / methotrexate / 5-fluorouracil (CMF) 4%, other regimens at 6% and no chemotherapy at 6%.
After 5 years, the estimated level of freedom from relapse of breast cancer was 93.0% (standard error [SE], 0,8%). Invasive disease-free survival was 87,6% (SE, 1,0%), and overall survival was 95,9% (SE, 0,6%).
Five-year indicators freedom from relapse of breast cancer in a remote location ranged from 92,3% (SE, 1,6%) to 95,5% (SE, 2,5%) for all regimens except CMF, which was associated with a frequency of 88,5% (SE 4,8%).
Cox models comparing either chemotherapy regimen to corrections for the lack of tumor size, age, extent and rate of relapse, estimated hazard ratios were 0.74 (95% CI, 0,32-1,69) for freedom from relapse of breast cancer remote location and 0.48. (95% CI, 0,29-0,80) for invasive disease-free survival. This indicates the "worst" outcomes for patients with a high relapse of 26 and above, who are not undergoing chemotherapy, the researchers note.
Initial results TAILORx «give clinicians high-quality data to inform personalized treatment recommendations for women," the statement said Sparano.
"This new analysis provides the largest collection of data on outcomes in patients with early breast cancer and high rates of recurrence. It confirms the importance of the use of the test to identify the minority of patients who would benefit significantly from the addition of adjuvant chemotherapy to endocrine therapy. "