Contralateral prophylactic mastectomy improves survival for certain patients
MedWire News: Contralateral prophylactic mastectomy (CPM) may only offer a survival benefit to younger women with early-stage estrogen receptor (ER)-negative breast cancer, US researchers have found.
To investigate the survival benefit associated with the increasingly popular CPM procedure, Isabelle Bedrosian (MD Anderson Cancer Center, Houston, Texas) and colleagues studied 107,106 women with breast cancer who underwent mastectomy 1998 and 2003. Of these patients, 8902 (8.3%) chose to undergo CPM.
The researchers stratified the patients by age, disease stage, and ER status, and then estimated the effect of CPM on breast cancer-specific survival. They found that CPM offered a clear survival benefit for women aged 18–49 years with stage I–II ER-negative cancer.
For this group of women, the 5 year-adjusted breast cancer survival rate was 88.5% with CPM and 83.7% without CPM, which equates to a 4.8% survival benefit with CPM. In contrast, the survival benefit was only 0.5% for women with ER-positive breast cancer who underwent CPM.
Of note, women with ER-positive tumors in the absence of prophylactic mastectomy had a lower overall incidence of contralateral breast cancer than women with ER-negative tumors, at 0.46% versus 0.90%. “This lower baseline risk for contralateral breast cancer may account for the lack of benefit associated with CPM in young women with early-stage ER-positive disease,” remark Bedrosian and co-authors.
The team found no reduction in breast cancer-related death associated with CPM in any of the subgroups of women older than 60 years. Among women between the ages of 50 and 59 years, CPM was associated with improved breast cancer-specific survival for women who had early-stage ER-negative disease and those with later-stage ER-positive disease.
Bedrosian et al conclude in the Journal of the National Cancer Institute: “A high, absolute lifetime risk of contralateral breast cancer, lack of availability of chemoprevention options, and a low risk of death from the index tumor combined, create the optimal conditions under which to consider CPM.”
They add: “With longer durations of follow-up, we anticipate that the degree of benefit associated with CPM in ER-negative breast cancer patients will increase.”
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By Laura Dean