Dive Brief:

• A significant minority of patients who undergo unilateral or bilateral mastectomies to treat breast cancer will require future imaging or biopsy of the operated site, according to a study by researchers at Mount Sinai.

• The study set out to learn whether opting for mastectomy over breast-conservation therapy (BCT) cuts the need for future screening and surveillance, as some women hope when they choose the more extensive surgical procedure.

• While the findings show many women who undergo mastectomies will require tests in the future, evidence from another study suggests the procedure is associated with a lower rate of imaging and biopsies than BCT.

Dive Insight:

Mastectomies are on the rise. From 1998 to 2011, the proportion of breast cancer patients who underwent bilateral mastectomies to treat unilateral disease increased from 5.4% to 29.7%. The jump covers a period in which evidence of the effectiveness of BCT grew and advances in imaging meant more cancers were caught earlier enough to treat with the more conservative approach.

Studies of the motivations of women who opt to undergo mastectomies over BCT have uncovered many reasons for the decisions. One factor is a desire to avoid tests and surveillance in the future.

The Mount Sinai team set out to show whether mastectomies fulfill this desire by looking back at the records of 441 patients who underwent unilateral or bilateral procedures at the hospitals' breast center from 2009 to 2015. The dataset featured between three and 75 months of follow up on the patients.

Among the unilateral mastectomy patients, 10% required ultrasound imaging and 6% underwent biopsies in the postoperative period covered by the dataset. The imaging and biopsy figures for the bilateral cohort are 15.5% and 8%, respectively.

“Given the extent to which the avoidance of future imaging plays a role in decision making by a subset of women who opt for mastectomy, this information is critical for patient understanding and for establishing reasonable postoperative expectations regarding the potential need for future imaging,” the authors wrote.

The study only looked at patients who underwent mastectomies and as such lacks a control arm that shows the rate of imaging and biopsy after BCT. Another study published earlier this year features aspects of such a comparison, although it lacks data on imaging and bilateral mastectomies.

The earlier study looked at 121,879 patients treated from 2000 to 2011. Among the women who underwent unilateral mastectomy, the estimated five-year bilateral biopsy rate was between 7.7% and 10.4%, depending on whether the patient was covered by Medicare or commercial insurance. In the whole-breast irradiation BCT group, the biopsy rate was over 15%.

The publication of two studies in quick succession means healthcare professionals and the women they treat now have access to far more data to guide their expectations of postoperative outcomes.