CPM: Contralateral Prophylactic Mastectomy

Understandably, when diagnosed with breast cancer, many women are of the opinion: "Just remove both my breasts so I won't have to worry anymore". Despite what may seem so obvious, the data simply do not support this assertion.

The performance of mastectomy in general has recently undergone significant scrutiny. There is simply no survival advantage offered by mastectomy over breast conservation. Therefore, removing a contralateral unaffected breast will have no clinical benefit.

The American Society of Breast Surgeons came out with a consensus statement regarding CPM in June, 2016:

CPM should be considered for those at significant risk of CBC (contralateral breast cancer)

Documented BRCA1/2 carrier.
Strong family history, but patient has not undergonegenetic testing.
History of mantle chest radiation before age 30 years.CPM can be considered for those at lower risk of CBC

Gene carrier of non-BRCA gene (e.g., CHEK-2, PALB2, p53, CDH1).
Strong family history, patient BRCA negative, no known BRCA family member.

CPM may be considered for other reasons

To limit contralateral breast surveillance (dense breasts, failed surveillance, recall fatigue).
To improve reconstructed breast symmetry.
To manage risk aversion.
To manage extreme anxiety. (This may be bettermanaged through psychological support strategies.)

CPM should be discouraged

Average-risk woman with unilateral breast cancer.
Women with advanced index cancer (e.g., inflamma- tory breast cancer, T4 or N3 disease, stage IV disease).
Women at high risk for surgical complications (e.g., patients with comorbidities: obesity, smoker, diabetes).
Woman tested BRCA negative with a family of BRCA-positive carriers.
Male breast cancer, including BRCA cancer

So, what are the facts?

In the ‘average’ patient, the risk of developing a second breast cancer is quite low, and related to patient age
- range between 25-30% in a 45 year old, depending on biomarkers
- CPM does not change the indications for adjuvant (additional) treatments such as chemotherapy, radiation or hormonal (endocrine) therapy
- If a contralateral breast cancer develops it tends to be less relevant (compared to the original cancer)
  - more likely to be screen detected (smaller)
  - less likely to have metastasized to lymph nodes
  - likely to have an excellent prognosis
The surgical risks of a contralateral mastectomy is higher than unilateral
Patient education regarding the potential risks and eventual benefits of prophylactic mastectomy is critical
However: a recent study from Mayo Clinic indicated an 83% patient satisfaction in women undergoing CPM & 84% would choose this option again