Poster display session: Breast cancer - early stage, locally advanced & metastatic, CNS tumours, Developmental therapeutics, Genitourinary tumours - prostate & non-prostate, Palliative care, Psycho-oncology, Public health policy, Sarcoma, Supportive care Poster Display session

213P - Early breast cancer classified as intermediate risk by the Prosigna assay: Characteristics and treatment strategy

Presentation Number
213P
Lecture Time
12:45 - 12:45
Speakers
  • Nawale Hajjaji (Lille, FR)
Location
Hall A3 - Poster Area Networking Hub, ICM M√ľnchen, Munich, Germany
Date
22.10.2018
Time
12:45 - 13:45

Abstract

Background

Genomic-based signatures are implemented in clinical practice to guide adjuvant treatment strategy in early breast cancer patients with luminal tumors. One of the main signatures, the PAM50-based Prosigna assay classifies patients into 3 risk categories based on their score of recurrence, thus providing clear guidance in low or high risk tumors. This study aimed at assessing in real life the proportion of patients with intermediate (ITD) risk results with the Prosigna assay, their tumor profile and the factors influencing treatment decision.

Methods

This monocentric retrospective study was conducted in 107 patients with luminal early-stage breast cancer treated at Oscar Lambret Cancer Center (Lille, France). Their tumors were analyzed with the Prosigna assay from July 2016 through April 2018.

Results

The Prosigna assay classified 15% of the patients in the low risk group, 41% were high risk, and 44% ITD risk. In this group, approximately one third were node negative and two third node positive. The tumor profiles with the highest proportion of ITD risk results had the following characteristics: 14≤Ki67≤20% and grade 2 in node negative or positive patients, or Ki67<14% and grade 2 in node positive patients (Table). 83% of the patients with an ITD risk result (39 of 47) were spared chemotherapy. Among them, 34 had luminal A and 5 luminal B tumors. Among the 8 patients proposed chemotherapy, luminal A and B tumors were evenly split. The main determinant of this decision was an estimated 10-year risk of relapse over 10 or 11%. Table: Prosigna risk groups distribution within patients’ main tumor profiles.

Prosigna risk groups
Low
Intermediate
High
Main Tumor Profiles (99 of 107 patients)n%n%n%Total (n)
14≤Ki67≤20% - G2 - N053374732015
14≤Ki67≤20% - G2 - N10105974117
Ki67<14% – G2 - N066033011010
Ki67<14% – G2 - N10136573520
Ki67>20% – G2 - N021743365012
Ki67>20% – G2 - N1019109111
Ki67>20% – G3 - N0 - T103434577
Ki67<14% – G1 - N12294571147

G: grade; N0/N1: node negative / positive (1 to 3); T1: tumor size ≤ 20mm

Conclusions

Our study showed that a significant proportion of patients were classified in the intermediate risk group, and most were spared chemotherapy. A specific guidance is needed in this risk group.

Legal entity responsible for the study

Centre Oscar Lambret.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.

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