Long-term Safety of Nipple Sparing Mastectomy in Women With High Penetrance Breast Cancer Susceptibility Genes in Breast Cancer

Condition(s) studied

Investigational drug(s) / intervention(s)

Nipple Sparing Mastectomy (NSM): Nipple sparing mastectomy (NSM) is a surgical procedure which removes all macroscopic breast glandular tissue while retaining the skin as well as the nipple areola complex.

Skin-Sparing Mastectomy (SSM): Skin sparing mastectomy (SSM) is a procedure that removes the nipple and areola complex along with all visible macroscopic breast glandular tissue.

Total (Simple) Mastectomy: Total (Simple) Mastectomy is a traditional mastectomy approach that removes the breast glandular tissue with a large overlying area of skin including the nipple and areola complex to allow for flat closure.

Study summary

Patients with a germline pathogenic variant (GPV) in high-penetrance breast cancer susceptibility genes who are considering risk reducing mastectomy (RRM) often strongly desire to keep their nipple areola complex but inquire as to whether it is safe to do so. Relative to traditional or skin sparing mastectomy (SSM) techniques, nipple sparing mastectomy (NSM) is associated with improved psychosocial and sexual well-being and is significantly better for body image and reducing feelings of disfigurement.

Despite this, guidelines have yet to endorse the use of NSM over other RRM techniques, stating that more data and longer follow-up are needed to confirm it as a safe and effective strategy in GPV carriers. As NSM was not routinely adopted in high-risk patient populations undergoing RRM before 2010, there has been little data to inform the long-term oncologic safety of NSM. Well-designed studies have reported low to negligible rates of subsequent breast cancer in BRCA1/2 carriers following NSM, but have been limited by short median follow-up of less than 3 years. The current study is designed to confirm, with longer follow-up, prior findings on the oncologic safety of NSM in unaffected BRCA1/2 carriers. The investigators will also expand data to other high-penetrance GPV carriers, including PALB2, CDH1, PTEN, and TP53, for whom there is little-to-no data on outcomes following RRM.

Eligibility

Primary outcome measure(s)

• Incidence of breast cancer following RRM — 10 years
  The primary outcome of interest is the incidence of breast cancer following RRM, defined as a histologically confirmed diagnosis of in situ or invasive breast cancer present within the nipple/areola, skin, subcutaneous tissue of the chest wall/reconstructed breast, or axillary lymph nodes. Patients with clinically occult invasive breast cancer diagnosed at the time of RRM (ie. on mastectomy pathology) will be excluded from the primary outcome analysis.

Trial sites (16)

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