Real-world prevalence, treatment and survival of "high risk" early breast cancer, with mandatory testing of gBRCA1/2 mutation according to the OlympiA trial inclusion criteria: Data from a population-based registry.

BACKGROUND

The results of the OlympiA study led to the approval of a PARP inhibitor (olaparib) as adjuvant treatment for early breast cancer (eBC) at high risk of relapse in patients with a germline BRCA1/2 mutation (gBRCAm). However, the proportion of patients in routine practice who meet the "high-risk" criteria applied in the OlympiA study, and for whom gBRCAm testing would now be mandatory, remains unknown.

PATIENTS AND METHODS

In this population-based study, we use unique data from the French specialized Côte d'Or Breast and Gynecological Cancer Registry, to assess the real-life proportion, and long-term prognosis of patients treated for eBC between 2005 and 2015 with standard treatment, and at "high risk" of relapse according to the OlympiA trial criteria.

RESULTS

We included 3483 patients treated for HER2-negative eBC (N = 380 with ER-, and N = 3103 with ER + tumor). We found N = 62 (1.8 %) patients with gBRCA1/2 mutations. A total of 494 patients (14.2 %) were classified as "high risk" according to the Olympia criteria; 55 % with ER-tumors, and 9.1 % with ER + tumors, respectively. Despite more intensive systemic treatments in "high risk" patients, 10-year overall survival was much worse in these "high risk" patients compared to the others: 60.1 % vs 83.8 % in ER-tumors, and 55.4 % vs 84.1 % in ER + tumors. Our estimates of net survival show an even greater difference.

CONCLUSION

This study provides real-life insights into the prevalence and prognosis of patients with high-risk eBC, in a context where the approval of adjuvant olaparib requires careful reorganization of care, so as not to overlook a patient with gBRCAm who could benefit from adjuvant olaparib.