Oncotype DX Test Predicts DCIS Recurrence
Results from a study by the Eastern Cooperative Oncology Group (ECOG) presented at the 2011 San Antonio Breast Cancer Symposium show an important advance in predicting local recurrence of ductal carcinoma in situ.
The study, part of ECOG’s larger E5194 clinical trial and not yet published in a medical journal, is the first time women at higher risk for local recurrence of DCIS could be identified from those at lower risk. This may allow doctors to provide more individualized treatment plans.
Background and Reason for the Study
DCIS, also called ductal carcinoma in situ, is cancer contained in the milk ducts of the breast. In the pathology report, DCIS is called stage 0 because it has not traveled outside the ducts to the lymph nodes or other areas of the body.
Typically, treatment for DCIS involves lumpectomy, removal of the area of DCIS and a rim of healthy tissue around it, followed by radiation therapy. Both treatments lower the risk of local recurrence, or return of DCIS to the same place. They are also thought to lower the risk for the DCIS returning and becoming invasive, when cancer moves into the ducts and has the ability to travel elsewhere in the body.
Adding radiation to lumpectomy has been shown to greatly reduce the risk of DCIS or invasive cancer returning compared to lumpectomy alone. But if the features of the DCIS suggest it is not likely to recur, forgoing radiation may be a treatment option. Today, this decision is made through a review of the pathology report that accounts for the size of the DCIS area, its grade, or rate of growth, and margin, the rim of healthy tissue.
The E5194 trial originally reported the five-year rates of local recurrence in 670 women who had lumpectomy, without radiation. It showed areas of DCIS of a certain size, grade and margin had low risk of recurrence with lumpectomy alone. Researchers concluded that new methods for more accurately measuring risk of recurrence were needed. They explored this using information from the Oncotype DX assay, a test that looks at the makeup of cancer cells predicting the chances of recurrence in hormone-positive, early-stage breast cancer that has not traveled to the lymph nodes.
Structure of the Study
Researchers collected the Oncotype DX results from 327 of the women included in the original E5194 clinical trial. Using a new formula, the researchers calculated a DCIS Score to predict the likelihood of cancer returning within 10 years of the initial DCIS diagnosis.
They were testing how well the DCIS Score predicted the recurrence rate for these women to see whether it was a good measure of future recurrence.
Results of the Study
Of the women included in the study, 75 percent were classified low risk, 14 percent intermediate risk and 11 percent high risk. When the DCIS Score was compared to rate of recurrence for these three groups, the researchers found a relationship that was statistically significant, or unlikely to have happened by chance. This suggests the DCIS Score is a good measure of possible recurrence.
What This Means for You
These results show the Oncotype DX DCIS Score may be a tool your doctor can use to predict the chances of DCIS returning. This may allow you to avoid radiation therapy, and impacts your care team’s ability to create a more individualized treatment plan for you.
This test is now available from Genomic Health, producer of the Oncotype DX assay. Ask your care team if the Oncotype DX DCIS Score is something they would consider using in determining the best treatment for you.
Solin, L.J., et. al. A Quantitative Multigene RT-PCR Assay for Predicting Recurrence Risk after Surgical Excision Alone without Irradiation for Ductal Carcinoma In Situ (DCIS): A Prospective Validation Study of the DCIS Score from ECOG E5194. Presented at the 34th Annual San Antonio Breast Cancer Symposium, Abstract S4-6