Impact of Recurrence Score on type and duration of chemotherapy in breast cancer

  • K. Willemsma University of British Columbia
  • W. Yip University of Waterloo
  • N. LeVasseur BC Cancer, University of British Columbia
  • K. Dobosz University of British Columbia
  • C. Illmann University of Waterloo
  • S. Baxter BC Cancer, University of British Columbia
  • C. Lohrisch BC Cancer, University of British Columbia
  • C. E. Simmons BC Cancer, University of British Columbia
Keywords: Oncotype DX, Recurrence score, Early stage, breast cancer, Chemotherapy, Personalized medicine, Adjuvant, Anthracyclines, Myelosuppression

Abstract

Background The use of Oncotype dx (Genomic Health, Redwood City, CA, U.S.A.) testing has been shown to change treatment decisions in approximately 30% of breast cancer (bca) cases, but research on how Recurrence Score testing has affected the type of chemotherapy offered is limited. We sought to determine if the availability of Oncotype dx testing resulted in a change to the type and duration of chemotherapy regimens used in the treatment of early-stage hormone receptor–positive bca.

Methods In a population-based cohort study, patients treated in the 2 years before the availability of Oncotype dx testing were compared with patients treated in the 2 years after testing availability. Charts were audited and divided into 2 groups: pre-Oncotype dx and post-Oncotype dx. The groups were compared for differences in duration of chemotherapy (12 weeks vs. >12 weeks), types of agents used (anthracycline vs. non-anthracycline), and myelosuppressive potential of the chosen regimen.

Results Of 834 patients who fulfilled the enrolment criteria, 360 fell into the pre-Oncotype dx era, and 474, into the post-Oncotype dx era. An increase of 11.2 percentage points, to 69.5% from 58.3%, was observed in the proportion of patients receiving short-course compared with long-course chemotherapy (p = 0.068). The proportion of patients prescribed anthracycline-containing regimens declined in the post-Oncotype dx era (47.7% pre vs. 32.2% post, p = 0.016). The selection of more-myelosuppressive chemotherapy protocols increased in the post-Oncotype dx era (67.4% pre vs. 78.8% post, p = 0.044).

Conclusions In the present study, the availability of Oncotype dx testing was observed to influence the choice of chemotherapy type in the setting of early-stage bca.

Author Biographies

K. Willemsma, University of British Columbia

Applied Health Sciences

W. Yip, University of Waterloo

Science

N. LeVasseur, BC Cancer, University of British Columbia

Medical Oncology

K. Dobosz, University of British Columbia

Medicine

C. Illmann, University of Waterloo

Science

S. Baxter, BC Cancer, University of British Columbia

Medical Oncology

C. Lohrisch, BC Cancer, University of British Columbia

Medical Oncology

C. E. Simmons, BC Cancer, University of British Columbia

Medical Oncology

Published
2019-11-01
How to Cite
Willemsma, K., Yip, W., LeVasseur, N., Dobosz, K., Illmann, C., Baxter, S., Lohrisch, C., & Simmons, C. E. (2019). Impact of Recurrence Score on type and duration of chemotherapy in breast cancer. Current Oncology, 27(2). Retrieved from https://current-oncology.com/index.php/oncology/article/view/5635
Section
Medical Oncology