San Antonio, TX—Assessing all eligible patients with breast cancer for recurrence risk with the 21-gene Oncotype DX assay at diagnosis could save $330.8 million annually by avoiding ineffective chemotherapy, according to data presented at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium. This analysis involved nearly 200,000 estrogen receptor (ER)-positive tumor samples. The Oncotype DX assay, which is approved in this subgroup of patients with breast cancer, yields a risk score for disease recurrence. “We believe that a low risk score on the assay is presently the most reliable biomarker for a chemotherapy-resistant phenotype, and we believe that the excess harm of chemotherapy outweighs the potential benefit of chemotherapy for those patients,” said lead investigator Joseph Ragaz, MD, FRCP, University of British Columbia, Vancouver.
The analysis of tumor samples from 196,967 ER-positive patients in the Genomic Health Database showed that a low 10-year recurrence risk score (<18) was more common among patients with axillary node-positive tumor than those with node-negative tumor. Of the nearly 14,000 patients with node-positive disease, 59% have a low risk score compared with 54% of those with node-negative disease. Major studies have shown no significant benefit of adjuvant chemotherapy in ERpositive breast cancer in patients with a low risk score.
Among the estimated 225,000 new cases of breast cancer diagnosed annually in the United States, 94,500 are ERpositive and are candidates for the Oncotype DX to assess their need for chemotherapy. At an estimated cost for chemotherapy of $15,000 per patient and $4000 per Oncotype DX assay, avoiding chemotherapy in patients with a low risk score would save $330.8 million annually, according to Dr Ragaz. Dr Ragaz advocated universal testing for all ER-positive patients, regardless of their axillary nodal status, suggesting that guidelines should be revised to avoid chemotherapy in all patients with a low risk score, regardless of nodal status as well. “Until prospective randomized trials confirm chemotherapy benefit among low risk score patients, its use among these chemotherapy-resistant cases should be considered investigational,” he said. “This is pretty strong stuff,” said Thomas J. Smith, MD, Harry J. Duffey Family Professor of Palliative Care, Johns Hopkins University, Baltimore, MD.
Dr Smith agreed that this approach has economic appeal to avoid wasteful spending and spare many women the unnecessary toxicity of chemotherapy. But he also pointed out that a much less-expensive alternative to the Oncotype DX assay can accomplish the same thing, including standard immunohistochemical (IHC) tests for estrogen, progesterone, and HER2 status, and tumor-cell proliferation marker Ki67. Emerging data suggest IHC4 can similarly predict recurrence risk in this patient population. Simon D.H. Holt, MD, Prince Philip Hospital, Llanelli, Wales, presented a favorable cost-effectiveness analysis of the Oncotype DX assay in UK oncology practices. He noted that the Ki-67 assay must be validated, because results can vary considerably among laboratories. He added that Oncotype DX has very tight quality assurance and is “certainly the best thing on the market.”—CH
