Abstract 175P
Background
Genomic tests are used as adjuvant chemotherapy decision support tool in HR + HER2- breast cancer (BC) patients. In France, the Health Authorities have recently advised indications for tests in case of intermediate risk of recurrence: pT1c-pT2 pN0-pN1mic grade 2 BC (the HA group). However, in routine practice, some tests were performed before and outside these indications. The aim of this study was to identify a population that benefits from performing a genomic test in real world setting.
Methods
We conducted a retrospective multicentric study (8 centers) including patients who had a Prosigna test between 2016 and 2021. We calculated a ratio defined as the number of tests to perform to avoid chemotherapy for 1 patient (the ratio). We did a cost-saving analysis using direct medical costs data from a previous study (ClinicalTrials.gov Identifier: NCT02813317).
Results
2331 patients had a Prosigna test during the study period. Among them, 840 tests were performed according to recommendations (HA group, 36%). The ratio was 2.8 [95%CI: 2.7-2.9] in the whole population, 2.3 [95%CI: 2.2-2.4] in the HA group and 3 [95%CI: 2.8-3;2] in the non HA group. Considering that in the absence of tests, all the patients were candidates for chemotherapy, the economic balance (direct medical costs over 1 year of care) was in favor of tests in the general population (-3.878.798€) and the HA group (-1.718.472€). The table presents the ratio by subgroups; in some subgroups the small number of patients did not allow to conclude (Italic in the table). The ratio was in or close to the 95% CI of the HA group ratio for: pT1a-pT2 pN0 Grade 2 tumors, pT1a-pT2 pN1 Grade 1 and Grade 2 tumors, pT3 pN0 Grade 2 tumors. Table: 175P
| n | No indication of chemotherapy | Ratio | |
| pT1a - pT1b | |||
| pN0 | |||
| Grade 1 | 21 | 17 | 1.2 |
| Grade 2 | 470 | 202 | 2.3 |
| Garde 3 | 130 | 26 | 5 |
| pN1 mic | |||
| Grade 1 | 9 | 7 | 3.8 |
| Grade 2 | 62 | 13 | 4.8 |
| Grade 3 | 8 | 0 | |
| pN1 | |||
| Grade 1 | 58 | 22 | 2.9 |
| Grade 2 | 109 | 37 | 2.6 |
| Grade 3 | 4 | 0 | 2.9 |
| pT1c - pT2 | |||
| pN0 | |||
| Grade 1 | 57 | 40 | 1.4 |
| Grade 2 | 750 | 324 | 2.3 |
| Grade 3 | 75 | 7 | 10.7 |
| pN1 mic | |||
| Grade 1 | 2 | 1 | 2 |
| Grade 2 | 101 | 17 | 5.9 |
| Grade 3 | 0 | ||
| pN1 | |||
| Grade 1 | 48 | 9 | 5.3 |
| Grade 2 | 207 | 35 | 5.9 |
| Grade 3 | 8 | 0 | |
| pT3 | |||
| pN0 | |||
| Grade 1 | 6 | 4 | 1.5 |
| Grade 2 | 76 | 37 | 2.1 |
| Grade 3 | 20 | 8 | 2.5 |
| pN1 mic | |||
| Grade 1 | 4 | 2 | 2 |
| Grade 2 | 8 | 1 | 8 |
| Grade 3 | 1 | 0 | |
| pN1 | |||
| Grade 1 | 15 | 9 | 1.7 |
| Grade 2 | 36 | 10 | 3.6 |
| Grade 3 | 1 | 0 |
Conclusions
For these subgroups, genomic tests could be considered to help the decision of adjuvant chemotherapy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Institut Curie.
Funding
Veracyte.
Disclosure
D. Hequet, R. Rouzier, F. Lerebours, E. Menet, F. Dalenc, V. Nicolai, N. Hajjaji, S. Lavau-Denes, V. Fermeaux, L. Texier, A. Cayre, E. Charafe Jauffret, A. Boucrauta, O. Tredan, J. Lopez: Financial Interests, Institutional, Funding: Veracyte.