Familial breast cancer: clinical response to induction chemotherapy or radiotherapy related to BRCA1/2 mutations status.
OBJECTIVE
BRCA1/2 germline mutations are associated with impaired DNA double-strand break repair. We tested whether breast cancers in BRCA1/2 mutation carriers were more responsive to induction treatments than in noncarriers.


METHODS
The BRCA1 and BRCA2 genes were screened for germline mutation in a retrospective cohort of 90 patients (with 93 tumors) with a family history of breast and/or ovarian cancer, treated with induction anthracycline-containing chemotherapy and/or radiotherapy. Median tumor size was 40 mm. Clinical responses and breast preservation rates were correlated to BRCA1/2 mutation status, and to other clinical and pathologic factors.


RESULTS
A complete clinical response was achieved in 15/39 (46%) BRCA1/2-mutated tumors and in 7/54 (17%) nonmutated tumors (P = 0.008). Complete or major clinical response rate was observed in 55 of the 74 tumors treated with induction chemotherapy (74.3%). The overall complete or major clinical response rate in the tumors treated with induction radiotherapy was 68% (13/19 tumors). Following induction treatment by either chemotherapy or radiotherapy, more breast-conserving treatments could be performed in mutation carriers than in noncarriers: the rates of breast preservation were 82% in BRCA1/2-mutated tumors and 63% in nonmutated tumors, respectively (P = 0.045). BRCA1 mutation was the sole predictor of breast conservation.


CONCLUSIONS
Breast conservation after induction treatment was higher in BRmut+ tumors, and clinical response was related to aggressive tumor features correlated with BRCA1/2 mutations. This suggests that impaired repair mechanisms related to the BRCA1/2 mutations increased the chemosensitivity and radiosensitivity of large breast cancers. Further studies will need to determine the long-term outcome in these patients.
Fourquet
Alain
A
Departments of Radiation Oncology, Institut Curie, Paris, France. alain.fourquet@curie.net
Stoppa-Lyonnet
Dominique
D
Kirova
Youlia M
YM
Sigal-Zafrani
Brigitte
B
Asselain
Bernard
B
D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D051017:Apoptosis Regulatory Proteins; D019313:BRCA1 Protein / Q000235:genetics*; D024682:BRCA2 Protein / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D005260:Female; D018095:Germ-Line Mutation / Q000235:genetics*; D006801:Humans; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011379:Prognosis; D011878:Radiotherapy; D012189:Retrospective Studies; D015996:Survival Rate
D051017:Apoptosis Regulatory Proteins; C118024:BLID protein, human; D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D024682:BRCA2 Protein; C551750:BRCA2 protein, human