Abstract 5627
Background
Benefit derived from adjuvant chemotherapy (CT) is doubtful in a high percentage of patients (pt) with hormone-receptor–positive HER2 negative early breast cancer. The 21-gene recurrence-score (RS) assay Oncotype DX, provide prognostic and predictive information. Results of the TAYLORx study have confirmed that most of patients with negative node status and RS > 25 can avoid CT without increasing their risk of relapse. However, pt < 50 years (y) and RS > 20 showed benefit with CT.
Methods
Aim: To analyse the impact of age using RS test to change the indication of adjuvant CT and the relationship between different clinical pathological factors and the RS value. We analysed 240 cases out of 251 RS test performed in the 3 ICO Centers during 2017-2018. We compared the adjuvant treatment initially planned according to institutional protocol with the treatment given after RS in the total cohort and in pt < 50 y. We performed a logistical regression analysis of pathological factors and RS.
Results
CT was indicated in all pt before knowing the RS results. Only 46 pt (19%) received CT after RS results. 14 out of 88 pt < 50 y received adjuvant CT (15%). 15 pt <50 y had a RS between 21-25, only 5 of them received CT, because in most of them, the RS was performed prior TAILORx results were published. Nowadays, all of these 15 pt would had received CT: 61/240 (25%). Clinical-pathological characteristics of the series are summarized in the Table. Of the risk factors analysed, only Ki67>25 (<0.001) and PR ≤ 20% (0.01) showed a statistically significant relationship with a higher probability of RS > 25 in a multivariate analysis.Table:
209P
| Age median (range) | 53 (19-76) <50 y 35.1% ≥50 y 64.9% |
| Tumor size median | 15 mm |
| Histological grade | G1 23% G2 69.7% G3 4.4% |
| Progesterone receptor | ≤20% 21% >20% 78% |
| Ki67 median (p25-75) | 20 (13,28) ≤14 27% 14-25 41% >25% 31% |
| Nodal status | pN0 57% pN1mic 15% pN1a 27% |
Conclusions
82% of pt of our series could avoid CT, however this proportion change after TAYLORx results in younger patients. Today 75% of these pt would had avoided CT. Ki67 > 25% and Progesterone Receptor ≤20% were the only pathological factors associated with an increased risk of RS > 25.
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.