New Data Suggest Oncotype DX Unnecessary in Some Cases of Low-Grade Cancer

March 2012, Vol 3, No 2

Grapevine, TX—A New Jersey research team is making the case for relying less on the Oncotype DX test for breast-cancer prognosis and instead focusing on conventional pathological analyses. Pathologists at Saint Barnabas Medical Center, Livingston, NJ, and Monmouth Medical Center, Long Branch, NJ, found that in a retrospective review of 90 cases, 88% of those who had the following 3 characteristics were in the Oncotype DX low-risk category:

  • Scarff-Bloom-Richardson (SBR) grade 1 tumor
  • Progesterone-receptor (PR) positivity
  • HER2 negativity.

Oncotype DX costs a little more than $2900, and not using it in these cases would have resulted in a total savings of $70,000, the investigators reported in a poster presentation of their results at the College of American Pathologists' 2011 annual meeting. "Clinicians are reluctant to change their practice simply because Oncotype DX has become an important component of their clinical algorithms," investigator Ashhad Mahmood, MD, told Value-Based Cancer Care (VBCC) after the meeting. "Further evidence delineating a subset of patients who may not require [Oncotype DX] testing may act as the impetus required to change clinical practice." Amelia Zelnak, MD, MSc, Assistant Professor of Hematology and Oncology, Winship Cancer Center, Emory University School of Medicine, Atlanta, GA, was contacted by VBCC to discuss the study. She takes the view that Oncotype DX is useful in many breast cancer cases because SBR grading is "subjective and can miss cases with a high risk of recurrence." "Oncotype DX is expensive," said Dr Zelnak, "but studies have shown that 5% of patients with low-grade tumors have high Oncotype DX scores. So, Oncotype DX really helps differentiate who should get chemotherapy and who shouldn't."

Dr Zelnak is referring to a 651- patient study that showed 5% of patients with an SBR grade 1 tumor had a high recurrence score (Paik S, et al. J Clin Oncol. 2006;24:3726-3734). The study by Dr Mahmood, Wendy Shertz, MD, and Byung-Kyu Kim, MD, involved cases submitted for Oncotype DX testing at Monmouth Medical Center between 2004 and 2010. Of the cases, 84 had final Oncotype DX results. The median age of the patients whose tumors underwent Oncotype DX testing was 57 years, and their median tumor size was 2.4 cm. Thirty (35.7%) cases were SBR grade 1; 24 of these were in the low-risk Oncotype DX category. Twenty-two of the 44 SBR grade 2 cases had a low-risk Oncotype DX score, 18 had an intermediate-risk score, and 4 had a high-risk score. Furthermore, 1 of the 6 SBR grade 3 cases had a low-risk score, 3 had an intermediate-risk score, and the remaining 2 cases had a high-risk score. Furthermore, 24 (80%) of the 30 SBR grade 1 cases also had a low-risk recurrence score. The remaining 6 had intermediate recurrence scores, with 5 of the 6 having scores in the lowest range of the intermediate category. The other case was PR-negative, with an elevated antigen Ki-67 proliferation index; these latter 2 measures are proved negative prognostic indicators, the investigators point out.

Overall, the team found that estrogen receptor (ER), PR, Ki-67, and HER2 status correlate highly with Oncotype DX categories. In addition, they uncovered a significant correlation between Oncotype DX categories and PR and HER2 status. Twenty-seven cases were SBR grade 1, PR-positive, and HER2-negative, and 24 (88%) of these had low-risk recurrence scores. If Oncotype DX testing had not been used in these 24 cases, the total savings would have been $70,000, the team calculated. Other research groups arrived at similar conclusions. For example, pathologists at the University of Pittsburgh Medical Center found that the Oncotype DX score is significantly correlated with tubule formation, nuclear grade, mitotic count, ER immunohistochemical score, PR immunohistochemical score, and HER2/neu status (Flana gan MB, et al. Mod Pathol. 2008;21:1255-1261). Furthermore, a team from the Montefiore Medical Center and the Albert Einstein College of Medicine in New York City determined that a mitotic-count score of >1 combined with a negative PR result as determined by pathologic assessment correlates significantly with an intermediate or high Oncotype DX score (Auerbach J, et al. Arch Pathol Lab Med. 2010;134:1697-1701). The Saint Barnabas Medical Center-Monmouth Medical Center team is expanding their study by continuing to collect and review cases submitted for Oncotype DX.

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