Study reveals puzzling paradox on bilateral mastectomy, breast cancer survival outcomes

Editor's Note

Medical professionals have long accepted that bilateral mastectomy does not improve survival outcomes for breast cancer patients. However, a study published in JAMA Oncology reveals a puzzling finding: Those who develop a second cancer in the other breast have a higher risk of death.

As detailed in a July 25 report from Stat, researchers caution that the new data should not alter the decision-making process about bilateral mastectomy. Rather, “the study raises key scientific questions about contralateral breast cancers and how breast cancer metastasizes and kills.”

According to the article, the study compared outcomes among 100,000 women diagnosed from 2000 to 2019 who underwent lumpectomy, unilateral mastectomy, or bilateral mastectomy. It found no significant survival difference between the groups after 20 years, with over 80% of women not dying from breast cancer regardless of the surgery type. However, those who developed cancer in the other breast faced a four-fold higher risk of death.

The reasons behind this paradox remain unclear, Stat reports. Some researchers suggest it may indicate systemic issues with the initial tumor or that the appearance of a second tumor triggers more aggressive metastatic behavior. Others consider the possibility of data artifacts influencing the findings.

Individualized counseling remains critical, researchers say. For example, one expert unaffiliated with the study told Stat that a double mastectomy may not improve survival but can offer other benefits, such as anxiety relief.