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Special populations: Early-stage breast cancer patients
The American Society of Clinical Oncology (ASCO) recently updated its guidelines for MammaPrint, a genomic tumor test that guides treatment decisions for patients with early-stage invasive breast cancer. The update was based on results from the MINDACT study (11/16/17).
The use of MammaPrint to guide treatment decisions on the use of adjuvant chemotherapy for patients with early-stage invasive breast cancer.
The Microarray in Node-Negative and 1 to 3 Positive Lymph Node Disease May Avoid Chemotherapy (MINDACT) is a study that looked at almost 7,000 European women with
early-stage invasive breast cancer. Researchers compared participants’ risk of recurrence using two separate means:
Participants with discordant clinical and genomic risk (either high clinical risk and low genomic risk or low clinical risk and high genomic risk) were randomly assigned to have chemotherapy or not. Results from the MINDACT study published August 2016 in the New England Journal of Medicine showed that 94.7% of patients with high clinical risk but low genomic risk as assessed by MammaPrint who did not receive chemotherapy were alive without distant metastasis at 5 years. This is 1.5% fewer than the number of similar patients who received chemotherapy, demonstrating that chemotherapy does not provide benefit for the vast majority of these patients.
Reducing overtreatment in patients with
early-stage breast cancer is important. Based on the results of the MINDACT trial, the American Society of Clinical Oncology (ASCO) recently updated their Clinical Practice Guidelines. While ASCO guidelines are regularly updated, guidelines are also revised when new, potentially practice-changing data is published. In August, 2017 ASCO updated it guidelines on the use of MammaPrint to help early-stage invasive breast cancer patients and health care providers to decide which women can forgo adjuvant chemotherapy based on the MINDACT trial results.
The MINDACT study showed that the MammaPrint test could predict which patients will have a favorable prognosis without
ASCO now recommends that MammaPrint may be used to help clinicians identify which early-stage invasive breast cancer patients may have limited benefit from adjuvant chemotherapy.
The MammaPrint test is appropriate for patients with hormone receptor-positive (ER–positive and PR-positive) HER2-negative breast cancer with 0-3 positive lymph nodes for whom Adjuvant! Online predicts a high clinical risk. However, no test is perfect. Some patients in the MINDACT study developed recurrent disease, even though MammaPrint testing suggested otherwise; other patients with poor MammaPrint scores remain disease free, even without chemotherapy.
If you have recently been diagnosed with early-stage invasive breast cancer, your physician may recommend the MammaPrint test. Based on the results, you may choose to forego adjuvant chemotherapy.
Other genomic tests are also used to predict the likelihood of early-stage breast cancer recurrence. ASCO In 2015, ASCO published a guideline update that found clinical utility for Oncotype DX, a 21-gene score that can predict recurrence in patients with ER-positive, node-negative breast cancer. An ongoing trial, RxPonder, is evaluating the efficacy of Oncotype DX in patients with node-positive disease.
From 2001 to 2007 researchers organized a large randomized trial in Europe to see whether a commercial genomic tumor test called MammaPrint could reduce overtreatment with chemotherapy in patients with early-stage invasive breast cancer. More than 6,600 women participated at 112 institutions in 9 nations. Each participant’s clinical risk of cancer recurrence was determined using a web-based tool called Adjuvant! Online. Patient’s tumors were also tested using MammaPrint, which produced a genomic score. Participants with discordant clinical and genomic risk (either high clinical risk and low genomic risk or low clinical risk and high genomic risk) were randomly assigned to receive adjuvant chemotherapy or not. The results, which were published in the New England Journal of Medicine in August 2016, suggest that approximately 46% of women with breast cancer who are at high clinical risk for recurrence might not benefit from adjuvant chemotherapy. As a result, ASCO updated guidelines on the use of MammaPrint to guide decisions on the use of adjuvant chemotherapy in an ASCO Special Article published in the Journal of Clinical Oncology in August, 2017.
Can MammaPrint, a commercially available genomic test, help to reduce overtreatment in patients with early-stage breast cancer?
MINDACT was a randomized trial that looked at 6,693 women with operable invasive breast cancer, 0 to 3 positive lymph nodes, and no distant metastases. Eligible patients were women between the ages of 18 and 70. Initially, only patients with node-negative disease were enrolled; however, the study was later amended in 2009 to include women with 1 to 3 positive nodes. Researchers determined participants’ clinical risk (using a modified version of Adjuvant! Online), genomic risk (using MammaPrint) and tumor samples.
The patients were divided into 4 main groups according to their clinical and genomic risk, and received either adjuvant chemotherapy or no therapy:
Among women with
early-stage breast cancer who were at high clinical risk and low genomic risk for recurrence and did not receive chemotherapy, the 5-year survival rate was 94.7%; the survival rate for those who did receive chemotherapy was 96.2%. This difference of 1.5 percentage points suggests that approximately 46% of women with early-stage invasive breast cancer who are at high clinical risk and low genomic risk do not receive benefit from adjuvant chemotherapy.
ASCO used the results of the MINDACT trial to revise its clinical guidelines regarding the use of MammaPrint for decision making regarding use of adjuvant chemotherapy for patients with early-stage invasive breast cancer. MammaPrint may inform patients with ER- or PR-positive, HER2-negative breast cancer and 0-3 positive lymph nodes and their clinicians whether or not to forego adjuvant chemotherapy. Although MammaPrint can be used to identify patients with high clinical risk who may receive limited benefit from chemotherapy, women with low clinical risk of recurrence did not benefit from chemotherapy, regardless of their MammaPrint risk group. Thus, ASCO does not recommend the use of MammaPrint for patients with low clinical risk.
Krop I, Ismaila N, Andre F, et al. “Use of Biomarkers to Guide Decisions on Adjuvant Systemic Therapy for Women With Early-Stage Invasive Breast Cancer: American Society of Clinical Oncology Clinical Practice Guideline Focused Update.” Journal of Clinical Oncology 35, no. 24 (August 2017) 2838-2847.
Harris L, Ismaila N, McShane L, et. al. "Use of Biomarkers to Guide Decisions on Adjuvant Systemic Therapy for Women With Early-Stage Invasive Breast Cancer: American Society of Clinical Oncology Clinical Practice Guideline." Journal of Clinical Oncology 34, no. 10 (April 2016) 1134-1150.
Cardosa F, Van t’ veer LJ, Boegerts J, et al. “70-Gene Signature as an Aid to Treatment Decisions in Early-Stage Breast Cancer.” New England Journal of Medicine 2016; 375:717-729 August 25, 2016