Distant disease-free interval, site of first relapse and post-relapse survival in BRCA1- and BRCA2-associated compared to sporadic breast cancer patients

Background Data on distant disease-free interval (DDFI) and the localization of the first distant metastasis (DM) in BRCA1- and BRCA2-associated breast cancer (BC) patients are as yet scarcely available. Patients and methods We identified 57 BRCA1-associated and 31 BRCA2-associated BC patients, diagnosed between 1980 and 2001, and developing DM disease before 2004, July 1. DDFI, the site(s) of first DM and post-relapse survival of these patients were compared with those of 192 sporadic BC patients. Results As compared to sporadic patients, BRCA1 patients developed less often bone DM (30% vs. 51%; P = 0.005), but tended to develop more often lung DM (26% vs. 16%; P = 0.07), and DM at multiple sites (44% vs. 32%; P = 0.11). In BRCA2-associated compared to sporadic patients, first DM more commonly occurred in lymph nodes (23% vs. 7%; P = 0.007) and at multiple sites (48% vs. 32%; P = 0.08). Adjuvant systemic therapy appeared to be most effective in BRCA2 mutation carriers. Post-relapse survival was worse for BRCA1- and better for BRCA2-associated patients as compared to sporadic patients, but differences disappeared after adjustment for ER-status, site of first DM and DDFI. Conclusion The site of first DM is different between BRCA1- and BRCA2-associated and sporadic BC patients. Differences in post-relapse survival could be explained by differences in site of first DM, in ER-status and in DDFI. Treatment efficacy may differ dependent on genetic status.