SAN ANTONIO, TX — Physicians and patients want to do everything possible to minimize the risk of breast cancer recurrence without incurring unnecessary toxicity from chemotherapy. While staging and subtype provide significant indications of risk, some women will progress despite apparently good indicators.

To help optimize decision-making, the MHS relies on a recurrence score to select patients for chemotherapy. The results have been excellent, reported a study released in conjunction with the 2018 American Society of Clinical Oncology Annual Meeting this weekend in Chicago.1

Researchers at the San Antonio Military Medical Center at Fort Sam Houston, TX, described use of an Oncotype DX database over a 10-year span at their facility. The retrospective cohort study analyzed results from 149 patients treated between 2007 and 2017. All but one patient had hormone-positive, node-negative breast cancer, a profile associated with generally good outcomes.

The Oncotype DX breast cancer assay uses 21 genes to analyze tumors to determine risk of recurrence. Scores below 18 predict a low risk of recurrence and indicate that hormone therapy alone will likely suffice. Scores above 30 are associated with higher risk that could be minimized with adjuvant chemotherapy.

The San Antonio cohort included 70 (47%) categorized as low risk, 60 women (41%) considered intermediate risk and 18 patients (12%) classified as high risk. Patients who had hormone negative or HER2 positive tumors were considered high risk.

Researchers found no correlation between patient age, ethnicity or score severity and risk classification. Higher histological grades, larger tumors and higher recurrence rates corresponded to higher risk scores.

Physicians’ recommendations for therapy generally followed the treatment suggested as appropriate by the recurrence score. Chemotherapy was offered to just 7% of the women with low-risk scores. In contrast, 52% of the intermediate-risk women received chemotherapy, as did 100% of those considered high risk.

Five-year progression free survival in this cohort supported the initial risk assessment, at 98.6% for low-risk women and 93.3% for women with intermediate risk. Among high-risk women, five-year progression free survival was 88.2%.

1Wan W, Aden J, Terrazzino S, Villarreal S, Delacruz WP. Application of a 21-gene recurrence score assay in node negative, hormone receptor positive breast cancer in a military treatment facility. 2018 ASCO Annual Meeting. Abstract e12567.