A study found that OncotypeDx, a genomic test, can help doctors decide if women diagnosed with DCIS (ductal carcinoma in situ) need radiation therapy.
The results were presented at the 2011 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 would be helpful.
A genomic test (also called a genomic assay) analyzes the activity of a group of genes that can affect how a cancer is likely to behave and respond to treatment. The test is performed on a sample of breast cancer tissue. Several genomic tests, including OncotypeDx, are being used by doctors to help figure out a woman's risk of early-stage, hormone-receptor-positive breast cancer coming back (recurrence) as well as how likely she is to benefit from chemotherapy. The genomic test results are a score that relates to recurrence risk. The higher the score, the greater the risk of recurrence and the more likely it is that a woman would benefit from chemotherapy.
This study looked at whether using the OncotypeDx test could help women diagnosed with non-invasive DCIS and their doctors make more informed treatment decisions. The researchers wanted to see if the OncotypeDx test did a good job of estimating the recurrence risk of DCIS and/or the risk of a new, invasive breast cancer developing in the same breast where the DCIS was. Using the OncotypeDx test this way might help doctors decide if the benefits of including radiation therapy in a woman's DCIS treatment plan outweigh the risks and inconvenience.
The OncotypeDx test was done on 327 DCIS tissue samples from women in another study looking at managing DCIS without radiation therapy after surgery. Each test resulted in a DCIS score that predicted recurrence risk. Recurrence included both another diagnosis of DCIS in the same breast OR a diagnosis of invasive cancer in that breast.
The researchers compared the OncotypeDx DCIS scores with the women's outcomes. Half the women were followed for 9 or more years. The other half were followed for shorter periods of time. Twenty women had a DCIS recurrence in the same breast and another 26 were diagnosed with invasive cancer in the same breast.
The study found that the DCIS score did help predict recurrence.
Women with low DCIS scores were unlikely to have a recurrence. Only 12% of these women had a DCIS recurrence or were diagnosed with invasive breast cancer during follow-up and most of these recurrences were DCIS, not invasive cancer.
Women with high DCIS scores were more than twice as likely to have a recurrence than women with low DCIS scores; 27% of women with a high DCIS score had a DCIS recurrence or were diagnosed with invasive breast cancer during follow-up. Almost half of these recurrences were invasive cancer.
The results suggest that the OncotypeDx 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. Based on the results, Genomic Health, the company that developed the OncotypeDx test, plans to make the score for DCIS available to doctors later this month.
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 if the OncotypeDx 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.
SAN ANTONIO (MedPage Today) -- A multigene assay for predicting recurrence of ductal carcinoma in situ (DCIS) showed potential for identifying low-risk patients who can avoid radiation therapy, according to a study reported here.
By use of the assay, researchers led by Lawrence J. Solin, MD, of Albert Einstein Medical Center in Philadelphia, successfully stratified patients into risk groups that correlated with subsequent rates of recurrence, which increased with the risk score generated by the test.
The DCIS risk score correlated significantly with recurrence rates, whether defined as DCIS and invasive cancer combined (P=0.02) or invasive cancer alone (P=0.01), as reported at the San Antonio Breast Cancer Symposium.
"Using a molecular-based assay, we have successfully identified patients at higher risk for recurrence and patients at lower risk," Solin said in a statement.
"This is an important advance for women with newly diagnosed DCIS. By predicting individual risk, physicians can provide a more tailored treatment program for each patient."
The assay evolved in response to a need for an accurate method to predict a woman's risk of recurrence after treatment of DCIS.
Solin and colleagues previously showed that selected patients with DCIS could be treated with surgery alone, avoiding the time, cost, and potential adverse events associated with irradiation (J Clin Oncol 2009; 27: 5319). They also found that the five-year local recurrence rate varied by age, tumor grade, and lesion size.
In an effort to the information provided by demographic and clinical variables, investigators analyzed results of gene-profile studies for 327 patients with DCIS. The patients participated in the Eastern Cooperative Oncology Group E5194 study, the first trial to evaluate surgical excision without radiation for DCIS.
All of the patients had low- or intermediate-grade DCIS ≤2.5 cm, or high-grade DCIS ≤1 cm.
Investigators examined gene-expression profiles derived from the Oncotype DXR assay, which involved use of quantitative reverse transcriptase-polymerase chain reaction to evaluate tumor specimens. Combining results of the gene assay with a published algorithm for recurrence, Solin and colleagues calculated a DCIS Score™.
The primary objective was to determine whether a significant association existed between the continuous DCIS Score™ and an ipsilateral breast event (defined as recurrent DCIS or invasive breast cancer).
During a median follow-up of 8.8 years, 20 patients had recurrent DCIS and 26 developed invasive cancer in the ipsilateral breast.
The 10-year breast event rates were 15.4% for patients who had low/intermediate DCIS and 15.1% for those with high-grade DCIS. Rates of invasive breast events were 5.6% and 9.8%, respectively, for the two DCIS categories.
On the basis of DCIS Score results, the investigators classified 75% of the 327 patients as low risk (score <39), 14% as intermediate (39 to 54), and 11% as high risk (≥55).
Rates of any ipsilateral breast event increased from 12.0% in the low-risk group to 24.5% in the intermediate-risk patients to 27.3% in high-risk patients. When the definition of ipsilateral breast event was limited to invasive breast cancer, the recurrence rates by DCIS Score were 5.1%, 8.9%, and 19.1%, respectively.
By multivariate analysis, three factors had statistically significant associations with occurrence of an ipsilateral breast event: menopausal status (HR 0.49, P=0.02), tumor size (HR 1.52 per 5 mm, P=0.01), and DCIS Score (HR 2.41, P=0.02).
"The DCIS Score will help physicians understand the underlying biology of DCIS for an individual patient and accurately gauge the risk for that person," said Solin. "As a result, the patient and physician can decide on the appropriate course of treatment based on a more complete understanding of the risk involved."
Solin had no disclosures. Other investigators disclosed relationships with Genomic Health, and investigators also included employees of Genomic Health.
Primary source: San Antonio Breast Cancer Symposium Source reference: Solin LJ et al. "A quantitative multigene RT-PCR assay or predicting recurrence risk after surgical excision alone without irradiation for ductal carcinoma in situ (DCIS): A prospetrive validation study of the DCIS Score from ECOG E5194" SABCS 2011; Abstract S4-6.
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