23P - Oncotype DX RS correlation with clinicopathologic risk factors and chemotherapy: Follow up based on TAILORx study

Background

Oncotype DX RS estimates the likelihood of recurrence and predicts the benefit from chemotherapy in early HR positive, node negative breast cancer. Patients are categorized into one of three tiers based on a calculated recurrence score (RS); low (<18), intermediate (18–30), and high (≥31–100). 2008 NCCN guidelines recommended adjuvant endocrine therapy for low RS, adjuvant chemoendocrine therapy for high RS. There was no clear chemotherapy recommendation for intermediate RS. In 2018 the TAILORx re-established RS categories; a score of less than 11 is low, 11-25 is intermediate and 26-100 is high, and provided evidence to treat patients with intermediate RS. We are Studying Oncotype Dx RS correlation with clinic-pathologic risk factors, and chemotherapy based on TAILORx tiers. We also looked the characteristics of patients with cancer recurrence.

Methods

Retrospective review of patients who had Oncotype DX test during 2012-2017 at National Cancer Center–Qatar.

Results

Of 54 patients studied 16(29.63%) had low RS, 32(59.26%) had intermediate RS, and 6(11.1%) had high RS. Univariate analysis showed that age (p<0.014), tumor grade (p<0.034), and Ki67% (cut-off 20%; p<0.013) were significantly different among Oncotype DX RS categories. There was no significant difference among Oncotype DX RS categories for tumor size (p<0.288) or PR status (cut-off 1%, p<0.3). Multivariate analysis showed that none of the clinical/pathological factors significantly predict the Oncotype DX RS. Chemotherapy was given to 1/16 (6.25%) patients with low, 7/32(21.9%) patients with intermediate, and 4/6 (66.7%) patients with high Oncotype DX RS (univariate analysis p<0.01). Tumor size was the only predictor of chemotherapy in multivariate analysis (OR 2.33 CI 0.33 - 3.86, p<0.020). 75% of patients who relapsed had RS 16-25, and were less than 50 years old in age.

Conclusions

Oncotype RS correlates significantly with individual clinical risk factors including age, tumor grade, Ki67%, chemotherapy treatment. Tumor size significantly predicts adjuvant chemotherapy. Breast cancer recurrence was noticed in younger patients with high intermediate RS (16-25), and adjuvant chemotherapy may be a reasonable option for these patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.