Importance: Bilateral mastectomy is increasingly used to treat unilateral breast cancer. Because it may have medical and psychosocial complications, a better understanding of its use and outcomes is essential to optimizing cancer care.
Objective: To compare use of and mortality after bilateral mastectomy, breast-conserving therapy with radiation, and unilateral mastectomy.
Design, Setting, and Participants: Observational cohort study within the population-based California Cancer Registry; participants were women diagnosed with stages 0-III unilateral breast cancer in California from 1998 through 2011, with median follow-up of 89.1 months.
Main Outcomes and Measures: Factors associated with surgery use (from polytomous logistic regression); overall and breast cancer–specific mortality (from propensity score weighting and Cox proportional hazards analysis).
More and more, women are getting bilateral mastectomies to treat unilateral breast cancer. Why? Cause they think it will help. They’re that afraid of breast cancer. This was an observational cohort study to see how common this practice is, and if it reduced mortality from breast cancer. And before you ask, yes they controlled for “age, race/ethnicity, tumor size, grade, histology, nodal and estrogen receptor/progesterone receptor status, receipt of adjuvant chemotherapy and radiation, neighborhood SES quintile, marital and insurance status, the SES composition of patients at the reporting hospital, care at an NCI-designated cancer center, and diagnosis year. ”
The study was large. More than 189,000 women were followed. The rate of bilateral mastectomy rose from 2% in 1998 to 12% in 2011. In young women less than 40 years of age, the rate rose from 4% in 1998 to 33% in 2011. It was more common in women with private insurance, who were non-Hispanic and white, and who received care at NCI-designated cancer centers.
Women who underwent breast conserving surgery with radiation had a 10-year survival of 83.2%. Women who had a bilateral mastectomy had 10-year survival of 81%. Women who had a unilateral mastectomy had a 10-year survival of 80%. What does this mean?
The study by Kurian et al in this issue of JAMA adds important new information to the evidence suggesting that CPM is unlikely to be associated with any significant survival advantage for the general population of patients with unilateral breast cancer. These investigators analyzed survival for nearly 200 000 California Cancer Registry patients with unilateral nonmetastatic breast cancer managed with BCS in 55% of cases, bilateral mastectomy/CPM in 6%, and unilateral mastectomy in 39%. With median follow-up of 89.1 months, 10-year survival for these 3 groups was 83.2%, 81.2%, and 79.9%, respectively. Although the unilateral mastectomy cases experienced a statistically significant survival disadvantage compared with BCS, the absolute difference was less than 4%. These findings support the rationale for encouraging BCS whenever feasible.
In other words, it appears that, for many women, breast conserving therapy with radiation may be the best option of all three. Yet women keep moving in the other direction, towards bilateral mastectomy. We need to come to grips with the fact that more isn’t always better. Sometimes less is.