Recurrence score predicted distant recurrence in patients treated with tamoxifen or anastrozole

San Antonio Breast Cancer Symposium

SAN ANTONIO — The Oncotype DX Recurrence Score independently predicted distant recurrence for patients with node-negative or node-positive hormone-receptor–positive breast cancer who were treated with tamoxifen or anastrozole.

Mitch Dowsett, PhD, of the Royal Marsden Hospital and team leader at the Breakthrough Breast Cancer Research Center in London, presented the results of the prospective study at the San Antonio Breast Cancer Symposium.

“These data confirm the performance of the recurrence score in postmenopausal ER-positive patients treated with tamoxifen in a large, more contemporary population,” Dowsett said. “This demonstrated for the first time that recurrence score is an independent predictor of distant recurrence in node-negative and node-positive hormone-receptor–positive patients treated with anastrozole.”

He and his colleagues evaluated tumor blocks from 1,231 patients with ER-positive breast cancer in the monotherapy arms of the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial. Distant recurrence occurred in 72 of 872 node-negative patients, 74 of 306 node-positive patients and six of 53 patients in whom node status was unknown.

The researchers found that the Oncotype DX Recurrence Score (Genomic Health; P<.001), tumor size (P<.001) and grade (P=.003) accurately predicted time to distant recurrence in node-negative patients. They observed similar rates for node-positive patients.

Nine-year rates for distant recurrence increased with recurrence score. For node-negative patients, nine-year distant recurrence rates were 4% for patients with recurrence scores <18; 12% for those with recurrence scores of 18-30; and 25% for those with recurrence scores ≥30. Looking at node-positive patients, distant recurrence rates were 17% for those with recurrence scores <18; 28% for those with recurrence scores 18-30; and 49% for those with recurrence scores ≥30.

The researchers found that comparing the high recurrence score with the low score yielded a HR of 2.7; intermediate score vs. low score yielded a HR of 1.8, according to Dowsett. – by Tina DiMarcantonio

For more information:

Dowsett M. #53. Presented at: the 31st Annual CTRC-AACR San Antonio Breast Cancer Symposium; Dec. 10-14, 2008; San Antonio.