Another study has confirmed that the Oncotype DX DCIS test helped predict the risk of recurrence in women diagnosed with DCIS and treated only with lumpectomy.
The research was published online on June 29, 2015 by the journal Breast Cancer Research and Treatment. Read “A population-based validation study of the DCIS Score predicting recurrence risk in individuals treated by breast-conserving surgery alone.”
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, the researchers followed 718 women diagnosed with DCIS for nearly 10 years. All the women had been treated by lumpectomy alone and 571 of the women had clear margins. After surgery, the researchers used the Oncotype DX DCIS test to calculate a recurrence score for each woman:
- 62.2% of the women had a low risk score
- 16.6% had an intermediate risk score
- 21.2% had a high risk score
During the nearly 10 years of follow-up, there were 100 recurrences of DCIS or invasive cancer in the same breast (local recurrence):
- 44 were DCIS
- 57 were invasive cancers
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 DCIS recurrence rates were:
- 5.4% for the low risk score group
- 14.1% for the intermediate risk score group
- 13.7% for the high risk score group
Local invasive disease recurrence rates were:
- 8% for the low risk score group
- 20.9% for the intermediate risk score group
- 15.5% for the high risk score group
“Most women diagnosed with DCIS will be candidates for [lumpectomy and] the decision to recommend additional treatment such as radiation relies on estimates of the baseline risk of local recurrence following treatment by [lumpectomy] alone," the researchers wrote. “This study confirms that the DCIS Score independently predicts and quantifies individualized recurrence risk in a population of patients with pure DCIS treated with [lumpectomy] alone.”
The results confirm earlier research showing 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.
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.