The Oncotype DX DCIS test helped predict the risk of DCIS (ductal carcinoma in situ) coming back (recurrence). Knowing this can help women and their doctors decide if radiation and/or hormonal therapy may be needed after surgery to reduce recurrence risk.
The study was presented at the 2014 San Antonio Breast Cancer Symposium.
DCIS is the most common form of non-invasive breast cancer. DCIS usually is treated by surgically removing the cancer -- lumpectomy in most cases. After surgery, hormonal therapy medicine may be recommended if the DCIS is hormone-receptor-positive (most are). Radiation therapy also is recommended for many women.
Routine radiation therapy after DCIS surgery was common in the past, but newer DCIS treatment guidelines say that radiation therapy after surgery doesn’t have to be given routinely to all women. At the same time, doctors aren’t always sure which women will benefit from radiation therapy, so a test to help guide the decision is helpful.
The Oncotype DX DCIS test is a genomic test that analyzes the activity of a group of genes that can affect how DCIS is likely to behave and respond to treatment. The test is performed on a sample of DCIS tissue. The Oncotype DX DCIS test offers results as a recurrence score. Depending on the recurrence score number, the DCIS has a low, intermediate, or high risk of recurrence. A low risk score is less than 39, and a high risk score is 55 or higher. A score of 39 to 54 is intermediate risk.
The recurrence score is considered in combination with other factors, including the size and grade of the DCIS, to make a decision about whether radiation and/or hormonal therapy makes sense after surgery.
In this study, researchers followed 571 women diagnosed with DCIS for more than 9 years. The women had been treated with lumpectomy alone, and no cancer was found in the margins. After surgery, the researchers used the Oncotype DX DCIS test to calculate a recurrence score for each woman.
The researchers found that the risk categories predicted by the Oncotype DX DCIS test paralleled the actual local recurrence rates in the women for both DCIS and invasive breast cancer. Local recurrence means the DCIS or invasive disease came back in the same breast.
Local DCIS recurrence rates were:
- 5.4% in the Oncotype DX low risk group
- 14.1% in the Oncotype DX intermediate group
- 13.7% in the Oncotype DX high risk group
Local invasive breast cancer recurrence rates were:
- 8.0% in the Oncotype DX low risk group
- 20.9% in the Oncotype DX intermediate risk group
- 15.5% in the Oncotype DX high risk group
“We found that the [Oncotype DX] DCIS score was a good predictor of whether a patient with DCIS who was treated with breast-conserving surgery alone would experience recurrence of DCIS or invasive breast cancer in the same breast,” said Eileen Rakovitch, M.D., associate professor and radiation oncologist at Sunnybrook Health Sciences Centre in Toronto, and who presented the study.
The results suggest that the Oncotype DX DCIS test does a good job of helping doctors estimate recurrence risk in women diagnosed with DCIS. The results could help doctors better judge which women diagnosed with DCIS are at high risk for recurrence or an invasive breast cancer diagnosis in the future and would benefit from radiation therapy after surgery.
Right now, the Oncotype DX DCIS test isn’t used that often, probably because it’s not included in the National Comprehensive Cancer Center Network (NCCN) guidelines. The NCCN is an alliance of the world’s leading cancer center. These NCCN centers collaborate on research, guidelines, and education to improve the care of people diagnosed with cancer.
If you've been diagnosed with DCIS, your doctor will recommend a treatment plan after surgery tailored to your specific recurrence risk for DCIS or invasive breast cancer. Your treatment plan may include radiation therapy, hormonal therapy, both, or neither. If you're deciding on treatments after DCIS surgery, you might want to ask your doctor if the Oncotype DX DCIS test might help figure out if you would benefit from radiation therapy. Armed with the best information possible, you and your doctor can decide on a treatment plan that makes the most sense for your unique situation.
The Breastcancer.org DCIS pages contain more information on DCIS symptoms, diagnosis, and treatment.
Read more news from the 2014 San Antonio Breast Cancer Symposium:
- Aromasin Plus Ovarian Suppression Reduces Recurrence Risk Better Than Tamoxifen Plus Ovarian Suppression in Premenopausal Women Who’ve Received Chemotherapy (with video)
- Low-Fat Diet and Weight Loss Improves Survival in Some Women
- Male Breast Cancer Is Different in Terms of Biology and Outcomes
- Abraxane Offers More Benefits Than Taxol When Given Before Surgery to Treat Early-Stage Disease
- Tamoxifen’s Benefits Long-Lasting for High-Risk Women
- Faslodex Offers Better Survival Than Arimidex as First Treatment for Women With Advanced-Stage Disease
- High Levels of Immune Cells in HER2-Positive Cancers May Mean Tumors Need Only Chemotherapy