Prophylactic mastectomy in BRCA1 and BRCA2 mutation carriers: very low risk for subsequent breast cancer.
OBJECTIVE
To examine the outcome of prophylactic mastectomy in a hospital-based series of BRCA1/2 gene mutation carriers with and without a history of breast cancer.


METHODS
A center-based consecutive series of 254 BRCA1/2 gene mutation carriers that had prophylactic mastectomy after a normal surveillance round including breast-magnetic resonance imaging were identified. One hundred forty-seven asymptomatic carriers underwent bilateral mastectomy and 107 symptomatic women had contralateral mastectomy after a mean cancer free interval of 3.6 years. All removed breasts were histopathologically examined.


RESULTS
In one asymptomatic BRCA2 carrier (0.7%) an occult small invasive breast cancer was diagnosed, while in 6 asymptomatic carriers (4.0% BRCA1 and 4.3% BRCA2) and in 5 symptomatic carriers (2.5% BRCA1 and 10.7% BRCA2) DCIS was detected at prophylactic mastectomy. No breast cancer occurred in the asymptomatic group after a postprophylactic follow-up period of 778 women-years. In the symptomatic carriers 1 invasive breast cancer was detected after 580 follow-up years. From age-, cohort-, and gene-specific reference data we calculated that 15 invasive first cancers in the asymptomatic carriers were prevented during follow-up.


CONCLUSIONS
One invasive breast cancer in 147 bilateral prophylactic mastectomies (0.7%) was detected, this makes a sentinel node procedure redundant and preoperative imaging vital. The prophylactic procedure is highly effective in preventing invasive breast cancer in BRCA1/2 mutation carriers. Since the remaining risk is less than 0.2%/woman-year, continued surveillance of the asymptomatic carriers is not warranted.
Department of Surgery, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Plesmanlaan, Amsterdam. r.kaas@nki.nl
Reinoutje
R
Kaas
Senno
S
Verhoef
Jelle
J
Wesseling
Matti A
MA
Rookus
Hester S A
HS
Oldenburg
Marie-Jeanne Vrancken
MJ
Peeters
Emiel J T
EJ
Rutgers
D000328:Adult; D019313:BRCA1 Protein / Q000235:genetics*; D024682:BRCA2 Protein / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics* / Q000517:prevention & control*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008408:Mastectomy; D008875:Middle Aged; D009154:Mutation; D012307:Risk Factors
D019313:BRCA1 Protein; D024682:BRCA2 Protein