[Relationship of clinicopathological features and chemotherapeutic outcomes in women with BRCA1 and BRCA2 mutation-negative familial breast cancer].

OBJECTIVE: To explore the relationship of clinicopathological features and response to neoadjuvant chemotherapy in women with BRCA1 and BRCA2 mutation-negative familial breast cancer. METHODS: A total of 6 200 women with breast cancer were treated at our hospital from October 2003 to December 2012. All subjects underwent genetic testing for BRCA1 and BRCA2 genes. Patients with BRCA1 and BRCA2 mutations were excluded. This cohort of 5 842 patients with BRCA1 and BRCA2 mutation-negative breast cancer was classified as two groups: familial breast cancer patients (n=480) and sporadic breast cancer patients (n=5 362). The clinicalpathological data and response to neoadjuvant chemotherapy of the 480 patients with BRCA1 and BRCA2 mutation-negative familial breast cancer and the 5 362 patients with BRCA1 and BRCA2 mutation-negative sporadic breast cancer were compared retrospectively. Then the influencing factors of response to neoadjuvant chemotherapy were analyzed. RESULTS: Among the BRCA1 and BRCA2 mutation-negative breast cancer patients, 4.4% of the patients were diagnosed before 30 years of age in the familial breast cancer group, significantly higher than that of 2.6% in the sporadic breast cancer group(P=0.020). 5.0% of the patients in the familial breast cancer group had bilateral breast cancer, significantly higher than that of 2.7% in the sporadic breast cancer group (P=0.004). Compared with BRCA1 and BRCA2 mutation-negative sporadic breast cancer patients, the relative risk of early-onset breast cancer (≤ 30 years) and bilateral breast cancer were 1.73 and 1.91, respectively, significantly higher than that in the BRCA1 and BRCA2 mutation-negative familial breast cancer cases (P=0.020 and P=0.004). 2 964 patients in this cohort of 5 842 case sreceived neoadjuvant chemotherapy.The pathologic complete response (pCR) rate was significantly higher in the BRCA1 and BRCA2 mutation-negative familial breast cancer group than in the BRCA1 and BRCA2 mutation-negative sporadic breast cancer group (21.7% vs. 14.0%, P=0.001). Independent factors associated with pCR in BRCA1 and BRCA2 mutation-negative breast cancer patients were tumor size less than 2 cm (P=0.012), histologic grade Ⅲ (P<0.001), triple-negative breast cancers (P<0.001), and BRCA1 and BRCA2 mutation-negative familial breast cancer(P=0.001). CONCLUSIONS: Compared with BRCA1 and BRCA2 mutation-negative sporadic breast cancer, BRCA1 and BRCA2 mutation-negative familial breast cancer is more likely diagnosed before the age of 30 years and has a higher risk to develop bilateral breast cancer. BRCA1 and BRCA2 mutation-negative familial breast cancers are more likely to respond to neoadjuvant chemotherapy than BRCA1 and BRCA2 mutation-negative sporadic breast cancer.