de Boniface J, Szulkin R, Johansson ALV.

Survival After Breast Conservation vs Mastectomy Adjusted for Comorbidity and Socioeconomic Status: A Swedish National 6-Year Follow-up of 48,986 Women.

JAMA Surg. Published online May 05, 2021. doi:10.1001/jamasurg.2021.1438.

Breast conserving surgery (BCS) is a surgery where the cancer of the breast is removed while as much of the normal breast is left behind as possible. The amount of breast tissue removed at the time of surgery depends on the size of the tumor, location of the mass and a patient’s breast size. Most women after BCS will need radiation therapy (RT). On the contrary mastectomy is removal of the entire breast; however, no muscles are removed from beneath the breast tissue. There are different types of mastectomy, such as skin-sparing mastectomy and nipple-sparing mastectomy, which are different cosmetic options. Depending on the size and location of the tumor, your breast surgeon will discuss whether or not both BCS and mastectomy are options for you.

Early trials showed that cancer outcomes were the same for women who underwent BCS followed by RT as women who underwent mastectomy. However, some more recent population-based trials showed that there was improved overall survival for patients who undergo BCS with RT compared to patients who had mastectomy with or without RT, which are both standard of care for small breast cancers. These more recent studies put into question mastectomy as an equally effective alternative to BCS for small breast cancers.

To address the question of whether mastectomy and BCS offered the same survival, de Boniface et al. did a prospective population-based cohort study looking at the association of socioeconomic factors and comorbidities with overall and breast cancer-specific survival. This study utilized prospectively collected data from the Swedish National Breast Cancer Register (NKBC). Interestingly the findings of Boniface et al showed that BCS had an improved overall and breast cancer-specific survival in node-negative patients. Their study specifically controlled for tumor biology, socioeconomic background, and comorbidities. This study provides additional data that there may not be a role for mastectomy for women who are eligible for breast conservation unless there is a strong family history or known genetic mutation.

The decision of what type of surgery is dependent on many variables that are taken into consideration by the multidisciplinary team such as cancer type, location, comorbidities, family history, and patient beliefs. When deciding on what type of breast cancer surgery, always talk with your surgeon about the options that are best for you.

It is interesting to see that BCS and mastectomy may not provide equivalent long-term results as we had once believed for women who are candidates for both options.