O. Abualkair (Riyadh, Saudi Arabia)
sulaiman alhabib hospitalAuthor Of 1 Presentation
57P - The Level of Agreement among Medical Oncologists on Adjuvant Chemotherapy Decision for Breast Cancer Pre and Post Oncotype DX result
Abstract
Background
Oncotype DX (ODX) assay identifies specific subset of patients with hormone-receptor (HR)-positive breast cancer (BC) who would benefit the most from adjuvant chemotherapy (CT). This study aimed to examine inter-agreement among several medical oncologists, as well as each oncologist intra-agreement on adjuvant CT decisions before and after Oncotype DX.
Methods
The data of 145 patients with HR-positive, HER2 negative BC were reviewed in retrospect. Traditional histopathological information with and without ODX RS was sent to 16 oncologists. The inter and intra-observer agreement among oncologists on prescribing adjuvant CT before and after ODX RS result were assessed. The result of ODX RS was interpreted as continuous variable and as per-risk level; low (0-17), intermediate (18-30) and high risk (≥ 31) groups. A P-value of < 0.05 was considered significant.
Results
The mean age at diagnosis ± SD was 51.9 ± 9.4 years. 76 patients (52.4%) were postmenopausal. The mean ODX RS was 17.8 ± 8.6 where 54.5% was low, 37.9% was intermediate and only 7.6% was high, respectively. Grade 2 (53.1%) and T(1) (49%) BC accounted for the majority. Positive (1-3) lymph nodes reported in one-third. The agreement among oncologists improved with the addition of ODX result from fair to moderate (kappa = 0.52; p <0.001). The addition of ODx RS result avoided CT in 20.4% and identified 9.1% as candidates for adjuvant CT (Kappa = 0.38; p <0.001). On average, an oncologist’s decision of prescribing adjuvant CT pre and post ODx had an agreement in 70.6% of the cases. The table shows agreement and disagreement between pre & post-ODX decision. Agreement and disagreement between pre & post-Oncotype decision when RS is sub-categorized No. of valid tests: 145x16 = 2320; p < 0.001.
Recurrence Score Decision Pre-Oncotype Dx RS Decision Post-Oncotype Dx RS Total No Yes Low-risk (1-17) No Count 781 19 800 % of Total 63.4 1.5 64.9 Yes Count 309 123 432 % of Total 25.1 10 35.1 Total Count 1090 142 1232 % of Total 88.5 11.5 100 Intermediate-risk (18-30) No Count 252 135 387 % of Total 28.6 15.3 44.0 Yes Count 160 333 493 % of Total 18.2 37.8 56.0 Total Count 412 468 880 % of Total 46.8 53.2 100 High-risk (31-100) No Count 10 55 65 % of Total 5.7 31.3 36.9 Yes Count 0 111 111 % of Total 0 63.1 63.1 Total Count 10 166 176 % of Total 5.7 94.3 100
Conclusions
We conclude that Oncotype DX RS boosted the level of agreement among oncologists and led to a decrease in the use of adjuvant chemotherapy compared to the pre-Oncotype DX recommendations.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.