Oncotype DX® Predicts Recurrence Risk in Node-negative and Node-positive Breast Cancer Treated with Tamoxifen or Arimidex

Oncotype DXR Predicts Recurrence Risk in Node-negative and Node-positive Breast Cancer Treated with Tamoxifen or Arimidex
Among postmenopausal women with early, hormone receptor-positive breast cancer treated with either tamoxifen (NolvadexR) or ArimidexR (anastrozole), the Oncotype DX test predicts the risk of distant cancer recurrence in both node-negative and node-positive patients. These results were published in the Journal of Clinical Oncology.

Oncotype DX is a genomic test that has been shown to predict the likelihood of distant cancer recurrence and the likelihood of chemotherapy benefit in women with early-stage, estrogen receptor-positive breast cancer that is treated with tamoxifen. The test evaluates the activity of 21 genes from a sample of the patient’s cancer to determine the patient’s Recurrence Score. The higher the Recurrence Score, the higher the risk of cancer recurrence. Oncotype DX has been added to U.S. medical guidelines for early-stage breast cancer.

The current analysis assessed how the Recurrence Score performed among women treated with the aromatase inhibitor drug Arimidex and among those with node-positive breast cancer.

The researchers collected information from 1,231 women who participated in the ATAC (Arimidex, Tamoxifen, Alone or in Combination) study. The study enrolled postmenopausal women with early, hormone receptor-positive breast cancer. Study participants received hormonal therapy with either tamoxifen or Arimidex.

The Recurrence Score (RS) predicted the risk of distant cancer recurrence among women with node-negative and node-positive breast cancer:

Among women with node-negative breast cancer, nine-year risk of distant cancer recurrence was 4% among women with a low Recurrence Score, 12% among women with an intermediate Recurrence Score, and 25% among women with a high Recurrence Score.Among women with node-positive breast cancer, nine-year risk of distant cancer recurrence was 17% among women with a low Recurrence Score, 28% among women with an intermediate Recurrence Score, and 49% among women with a high Recurrence Score.

The relationship between Recurrence Score and risk of distant cancer recurrence was similar regardless of the type of hormonal therapy that the women received.

This study suggests that the Oncotype DX test provides information about risk of distant cancer recurrence in both node-negative and node-positive, hormone-receptor positive breast cancer. Furthermore, Oncotype DX was predictive of distant recurrence risk among women treated with tamoxifen as well as women treated with Arimidex.

Reference: Dowsett M, Cuzick J, Wales C et al. Prediction of risk of distant recurrence using the 21-gene recurrence score in node-negative and node-positive postmenopausal patients with breast cancer treated with anastrozole or tamoxifen: a TransATAC study. Journal of Clinical Oncology [early online publication]. March 8, 2010.

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Oncotype DX DCIS Score Predicts Recurrence Risk for Women with DCIS

A DCIS Score generated by the Oncotype DX breast cancer test provides information about how likely it is that breast ductal carcinoma in situ (DCIS) will recur. This may help guide decisions about whether women with DCIS need radiation therapy after breast-conserving surgery. These results were presented at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium.????

Ductal carcinoma in situ refers to a condition in which abnormal cells are found within a breast duct but have not spread outside of the duct to other tissues in the breast. It is most commonly detected by screening mammography. If not treated, some cases of DCIS may progress to invasive breast cancer.?

Treatment for DCIS may involve breast-conserving surgery (lumpectomy) or mastectomy. For DCIS patients who choose breast-conserving surgery, additional treatment with radiation therapy has been shown to reduce the risk of recurrence, but may not be necessary for all women. If the characteristics of the DCIS suggest that it is unlikely to recur, surgery alone (without radiation therapy) may be an option.??

The Oncotype DX breast cancer test was originally developed to provide information about recurrence risk and need for chemotherapy to certain groups of women with early-stage, invasive breast cancer. The test has been added to US medical guidelines for this purpose.????

To determine whether the test can also predict recurrence risk in women with DCIS, researchers developed a DCIS Score that can be generated by the test. The ability of the DCIS Score to predict recurrence risk was evaluated among 327 women with DCIS who had participated in an earlier clinical trial of DCIS treatment. The women had been treated with breast-conserving surgery but had not received radiation therapy.????

Three-quarters of the patients had a low risk of recurrence based on the DCIS Score. These patients may not need radiation therapy after breast-conserving surgery.?Among women with a low risk of recurrence based on the DCIS Score, the likelihood of any kind of local recurrence (a recurrence that was either DCIS or invasive breast cancer) was 12 percent. The likelihood of a recurrence that involved invasive breast cancer 5 percent.?Among women with a high risk of recurrence based on the DCIS Score, the likelihood of any kind of local recurrence was 27 percent. The likelihood of a recurrence that involved invasive breast cancer was 19 percent.?

These results suggest that the Oncotype DX DCIS Score provides information about the risk of recurrence among women with DCIS. This information may help guide decisions about whether radiation therapy is necessary.?

Reference: Solin LJ, Gray R, Baehner FL. 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 2011 CTRC-AACR San Antonio Breast Cancer Symposium. December 6-10, 2011. Abstract S4-6.?

Posted December 13, 2011?

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