CLINICAL BENEFITS OF CONTRALATERAL PROPHYLACTIC MASTECTOMY FOR WOMEN WITH UNILATERAL EARLY-STAGE BREAST CANCER

Title:

Clinical Benefits of Contralateral Prophylactic Mastectomy for Women with Unilateral Early-stage Breast Cancer

 

Purpose:

To examine the survival benefits of contralateral prophylactic mastectomy (CPM) in women with early-stage breast cancer without a BRCA mutation or additional risk factors. 

Methods:

We developed a Markov model to compare CPM with no CPM among women with early-stage breast cancer without a BRCA mutation.  Probabilities for developing contralateral breast cancer (CBC), dying from CBC, dying from the primary breast cancer, and the reduction in CBC due to CPM were estimated from the published literature.  From the parameterized model, we estimated the life expectancy (LE) gain and absolute 20-year survival difference of CPM among cohorts of women newly diagnosed with unilateral breast cancer defined by age (40-60 years), estrogen receptor (ER) status (positive or negative) and stage of cancer (I or II). 

Results:

LE gain from CPM ranged from 0.13 to 0.59 years for women with stage I breast cancer and 0.08 to 0.29 years for those with stage II breast cancer (table).  Twenty-year absolute survival differences ranged from 0.56% to 0.94% for women with stage I breast cancer and 0.36% to 0.61% for women with stage II breast cancer.  CPM was more beneficial among younger women, stage I, and ER negative breast cancer.  

Conclusions:

Although CPM dramatically reduces the risk of CBC, the maximum life expectancy gain is about 7 months with a less than 1% 20-year survival difference for all age, ER status, and cancer stage groups.  Decision models may be helpful for physicians when counseling patients on prophylactic breast cancer risk reduction strategies.

Table:  LE Gains from CPM

	Life Expectancy (yrs)
Characteristics	CPM	No CPM	LE Gain
40 yo, ER+, Stage I	36.77	36.30	0.47
40 yo, ER-, Stage I	36.76	36.17	0.59
40 yo, ER+, Stage II	24.16	23.92	0.24
40 yo, ER-, Stage II	24.15	23.86	0.29
50 yo, ER+, Stage I	29.72	29.45	0.27
50 yo, ER- , Stage I	29.71	29.38	0.33
50 yo, ER+, Stage II	20.89	20.74	0.15
50 yo, ER-, Stage II	20.88	20.70	0.18
60 yo, ER+, Stage I	22.54	22.41	0.13
60 yo, ER-, Stage I	22.53	22.37	0.16
60 yo, ER+, Stage II	16.98	16.90	0.08
60 yo, ER-, Stage II	16.98	16.88	0.10