Adjuvant therapy after preoperative treatment for breast cancer

The increase in the use of preoperative chemotherapy has raised new questions regarding how to optimize locoregional and systemic adjuvant treatment. When patients are given preoperative systemic therapy, the preferred therapeutic regimens are the same as those established as safe and active in the adjuvant setting. At present, no data suggest that systemic treatment should be tailored, in one direction or another, based on initial tumor response or lack thereof (except for frank disease progression while on treatment), or based on the extent of residual disease.

Adjuvant locoregional and systemic treatment after preoperative chemotherapy for breast cancer is still controversial. No high-quality data from prospective trials are available; nevertheless, locoregional therapy decisions should be based on both pretreatment and the clinical extent of disease. Sentinel node biopsy can be performed before and after preoperative therapy in patients with clinical N0 disease at diagnosis. It is not clear whether resection margins should be differently evaluated after preoperative therapy than in the standard setting. The success of breast-conserving surgery depends on careful patient selection and on an adequate surgical technique that achieves negative margins. Adjuvant breast irradiation is indicated for all patients who undergo breast conservation; for patients treated with mastectomy, chest-wall and regional nodal radiation must be done in those who present with clinical stage III disease or who have histologically positive lymph nodes at diagnosis.

Additional studies are needed to determine the value of postmastectomy irradiation in clinical stage II breast cancer, as well as to determine the convenience of adjuvant systemic therapy in patients who do not achieve a good pathological response with preoperative treatment. Multidisciplinary treatment teams are critical in order to improve therapeutic management of these patients.