No mortality benefit with bilateral mastectomy vs breast-conserving surgery

1. From 1998 to 2011, there was a substantial increase in the use of bilateral mastectomy for the treatment unilateral early-stage breast cancer in California.

2. While unilateral mastectomy demonstrated the highest mortality rates of the three surgical treatment options examined, bilateral mastectomy was not associated with lower mortality than breast-conserving surgery plus radiation.

Evidence Rating Level: 2 (Good)     

Study Rundown: The number of breast cancer patients choosing to pursue elective bilateral mastectomy has risen over the previous years. However, a limited amount of information is known regarding both the prevalence of its use and the efficacy of its outcomes when compared to other surgical treatment options. This study examined the efficacy of three surgical therapies for early-stage breast cancer – bilateral mastectomy, breast-conserving surgery with radiation, and unilateral mastectomy – and characterized the associated mortality outcomes. During the study period (1998 to 2011), there was a significant increase in the use of bilateral mastectomy at an annual rate of 14.3%. Bilateral mastectomy was found to have a comparable mortality rate to breast-conserving surgery with radiation. Unilateral mastectomy was associated with higher mortality compared to the other two treatment options.

This study is novel as it is the first comparison of these three surgical options for early-stage breast cancer. The observational study design was useful in evaluating the efficacy of surgical options on mortality, particularly given the limited feasibility of a randomized controlled trial in this patient population. Stratification based on age, ethnicity, martial status, SES, and insurance coverage provided insight into the patients accessing these various treatment options, and a focused risk of mortality. Limitations of this study include loss to follow-up, selection bias, and confounding. Additionally, several pertinent patient factors were not measured, such as comorbidities and family cancer history, which could have impacted patient outcomes. Overall, however, this study highlights the lack of evidence supporting this observed increase in bilateral mastectomy rates.

Click to read the study, published today in JAMA

Click to read the accompanying editorial, published today in JAMA

Relevant Reading: Increasing use of contralateral prophylactic mastectomy for breast cancer patients: a trend toward more aggressive surgical treatment

In-Depth [observational cohort]: This study compared the use and associated mortality of three surgical treatment options in 189,734 women diagnosed with unilateral early-stage breast cancer from 1998 to 2011 in California. The rate of bilateral mastectomy increased by 14.3% (95% CI, 13.1-15.5%) annually, from 2.0% (95% CI, 2.3-5.0%) in 1998 to 12.3% (95% CI, 13.1-15.5%) in 2011. This increase was greatest in patients less than 40 years of age. Women treated with bilateral mastectomy were also more likely to be non-Hispanic white, privately insured, and of higher socioeconomic status (SES). Meanwhile, those treated with unilateral mastectomy were more likely to be Hispanic or Asian, publicly insured, and of lower SES. Unilateral mastectomy demonstrated a 20.1% 10-year mortality rate while bilateral mastectomy demonstrated and breast-conserving surgery with radiation demonstrated rates of 18.8% and 16.8%, respectively (no significant change).

Image: PD

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