Initial experience with the Oncotype DX assay in decision-making for adjuvant therapy of early oestrogen receptor-positive breast cancer in Hong Kong.

Objective: To examine the impact of the 21-gene Oncotype DX Breast Cancer Assay on the adjuvant treatment decision-making process for early-stage breast cancer in Hong Kong.

Design: Retrospective study.

Setting: Private hospital, Hong Kong.

Patients: Study included cases of early-stage breast cancer (T1-2N0-1M0, oestrogen receptor-positive, human epidermal growth factor receptor 2-negative) that were presented at a multidisciplinary breast meeting at a single site. Cases were selected for Oncotype DX testing with the assistance of Adjuvant! Online. The recommendations for adjuvant therapy before and after obtaining the Oncotype DX Recurrence Score results were analysed.

Results: A total of 154 cases that met the inclusion criteria were discussed at our multidisciplinary breast meeting. Of these, 64 cases with no clear recommendation by the Meeting Panel were selected for this study and reviewed. The distribution of Recurrence Score results was similar to that reported by others, with a somewhat higher proportion of low Recurrence Scores. Treatment recommendation was changed for 20 (31%) patients after the Oncotype DX result was received. Of the changes in treatment decisions, 16 (80%) were changes to lower-intensity regimens (either equipoise or hormonal therapy). The number of cases receiving an equipoise recommendation decreased by nine (82%), based on the additional information provided by the Oncotype DX test.

Conclusion: The Oncotype DX Recurrence Score information impacts the decision-making process for adjuvant therapy for early-stage breast cancer in the multidisciplinary care setting in Hong Kong. A larger-scale study is required to gain more experience, evaluate its impact more thoroughly, and assess its cost-effectiveness.