The media has been recently focused on this (at least when not reporting on ISIS). It’s likely that many of you have heard about the report that came out comparing mortality rates for three types of surgery for breast cancer: bilateral mastectomy (both breasts), unilateral mastectomy (single) or lumpectomy with radiation. The article that the media has been quoting was published in the September 3 issue of JAMA.
The reported study included 189,734 California women who were diagnosed with breast cancer in stages 0 to 3 between January 1998 and December 2011. The researchers reviewed the types of treatments they received, their follow up and the death certificates of those who died during the follow up. They excluded those women who were diagnosed after 2010 because of incomplete mortality data. If appropriate records were not available they also eliminated some of the patients, so basically, the final analysis included 174, 917 women whose medium follow up time was 89.9 months. (I am not sure you wanted all these numbers but I thought I would try to be as exact as possible,at least at the beginning of this website article.)
What they found was that the rate of bilateral mastectomy increased from 2% in 1998 to 12.3% in 2011 and this represented an annual increase of 14.3%. Women younger than 40 were most likely to have an increased rate of bilateral mastectomy which went from 3.6% in 1998 to 33% in 2011. This procedure was more often used by non-Hispanic white women, those with private insurance and those who received care at a National Cancer Institute (NCI) designated cancer center (8.6% among NCI cancer center patients versus 6% among non-NCI cancer patients). Unilateral mastectomy (obviously on the side diagnosed with breast cancer) was more often used by racial/ethnic minorities and those with public/Medicaid insurance (up to 52%). Breast conserving surgery with radiation was done in about 55% of all patients but again varied according to age, insurance and tumor size.
The important conclusions of the study was that compared with breast conserving surgery (lumpectomy) with radiation that had an overall ten-year mortality of 16.8%, unilateral mastectomy was associated with a higher all-cause mortality and a ten-year mortality rate of 20.1%. There was no significant mortality difference between lumpectomy and radiation and bilateral mastectomy (in which the ten-year mortality rate was 18.8%).
I know these mortality rates seem high. But there was a huge variability in cancer stage between zero and stage III, so the rates included the higher stage cancers. The study was not randomized and treatment was dependent on a lot of other factors including size of the tumor, tumor features that suggested a poor prognosis as well as lymph node metastases, receptor status and genetic changes which could worsen the prognosis. And as new reconstruction procedures were developed (which look better and allow symmetry), it was likely that some women would choose to have bilateral rather than unilateral mastectomy. Finally, younger women who have a longer period of time for risk of recurrent or new cancer or have a higher probability of carrying genetic mutations were more likely to chose to have surgery on both breasts.
The conclusion of the authors was that although the use of bilateral mastectomy increased throughout California through 2011, overall it was not associated with lower mortality than that achieved with breast conservativeness surgery and radiation. Unilateral mastectomy was actually associated with higher mortality than the other two surgical options.
I want to add my own take on this… it is an important study, but the fact that so many stages of breast cancer were lumped together and prognostic features were varied, there are significant drawbacks. Today with MRI, genetic tumor analysis and profiling, the prognosis of a woman’s breast cancer is more defined, allowing therapy to be targeted and of course improved. When deciding on the course of surgery, considerations of family history, ability to follow up with therapy and surveillance as well as complications of radiation and/or extensive surgery warrant careful consideration. Insurance status is an issue and is unfortunate; hopefully in the future no woman will be denied appropriate care. Every woman who has a diagnosis of breast cancer should carefully consider all choices of therapy with her physicians. Taking a few weeks to consider these will not make a difference in the outcome. This study should be part of the discussion.