Breast Cancer Conservation Therapy

Excerpt

Breast cancer ranks among the leading causes of female cancer-related deaths in the world. Surgical management remains the standard of care for non-invasive and localized invasive breast cancer, which may get combined with systemic endocrine therapy, chemotherapy, and/or radiation. With the publication of the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-06 trial, which showed equivalent disease-free survival, distant disease-free survival, and overall survival amongst women undergoing partial mastectomy with irradiation compared to radical mastectomy, breast conservation therapy (BCT) became standard of care for patients with tumors under 4 cm.

These results received confirmation in multiple studies, including a 20-year follow-up of the NSABP B-06 trial, where partial mastectomy followed by breast radiation continues to be appropriate in the management for smaller invasive breast cancer tumors. Additionally, breast conservation therapy, when combined with radiation, became the standard of care for localized intraductal breast cancers (ductal carcinoma in situ: DCIS). This development occurred after the NSABP B-17 trial, where the addition of radiation significantly decreased the recurrence rate of non-invasive and invasive breast cancers.

Identified advantages to breast conservation therapy include reduced operative time, diminished psychological burden when compared with mastectomy, improved cosmetic outcomes, and limited side effects. However, other studies have demonstrated no significant difference in depressive symptoms at one year post-operatively between women who underwent a total mastectomy, breast conservation therapy, and breast reconstruction.

Proper staging is critical for determining the appropriate clinical treatment course and surgical planning. In 2018, the American Joint Committee on Cancer (AJCC) released the eighth edition of the Cancer Staging Manual for Breast Cancer. This staging includes the T (tumor), N (node), and M (metastases) staging, but incorporated biologic markers into the traditional staging system. Factors including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), tumor grade, and multigene assays were included to aid in determining prognosis and therapy as determined by a Clinical and Pathologic Prognostic Stage Group.