MS4-3: Radiation for Patients Treated with Neoadjuvant Chemotherapy.
Authors: Buchholz TA 
Published: June 2012

Abstract
The increased use of neoadjuvant systemic therapy for patients with stage II or stage III breast cancer has raised a number of important questions concerning local-regional treatments, particularly within the field of radiation oncology. Historically, the indications for radiation use after mastectomy and treatment of regional lymph node fields were determined on the basis of pathological extent of disease. It is clear that neoadjuvant systemic treatments changes the pathological extent of disease in most cases. Additional data are needed to determine how the degree of disease response should guide radiation oncologists to the tailor treatment approaches. Specifically, there is potential for minimizing local-regional treatments in those with favorable responses and intensifying therapy for those with unfavorable responses. One surgical success in de-intensification of local treatment has been the ability to safely treat with breast conservative therapy for selected patients with advanced primary tumors that respond favorably to neoadjuvant chemotherapy. It may also be possible to limit radiation treatments for selected patients with favorable disease response. Specifically, data from M. D. Anderson and the NSABP suggest that patients with clinical stage II breast cancer who have negative axillary lymph nodes after neoadjuvant chemotherapy have low rates of recurrence after mastectomy and low rates of regional lymph node recurrences. (1-4) This may permit a more selective approach to using radiation after mastectomy or regional lymph node radiation for patients with stage II disease. In contrast, data suggest that patients who present with clinical stage III disease maintain high rates of local-regional recurrence independent of treatment response and therefore all such patients are recommended to postmastectomy and regional lymph node irradiation.(1,3)
Patients with a poor response to neoadjuvant chemotherapy unfortunately remain a therapeutic challenge. In addition to high persistent rates of distant metastases, these patients have clinically relevant rates of local-regional recurrence despite mastectomy and high dose postmastectomy radiation. For such patients, new protocols are needed to evaluated novel systemic approaches and radiation sensitizer strategies.
1. Buchholz TA, et al. Predictors of local-regional recurrence after neoadjuvant chemotherapy and mastectomy without radiation. J Clin Oncol. Jan 1 2002;20(1):17–23.
2. Garg AK, et al. T3 disease at presentation or pathologic involvement of four or more lymph nodes predict for locoregional recurrence in stage II breast cancer treated with neoadjuvant chemotherapy and mastectomy without radiotherapy. Int J Radiat Oncol Biol Phys. May 1 2004;59(1):138–145.
3. McGuire SE, et al. Postmastectomy radiation improves the outcome of patients with locally advanced breast cancer who achieve a pathologic complete response to neoadjuvant chemotherapy. Int J Radiat Oncol Biol Phys. Apr 5 2007.
4. Mamounas E, et al. Predictors of locoregional failure (LRF) in patients receiving neoadjuvant chemotherapy (NC): Results from combined analysis of NSABP B-18 and NSABP B-27. Abstracts from the ASCO 2010 Breast Cancer Symposium [2010; http://www.asco.org/ASCOv2/Meetings/Abstracts?&vmview=abst_detail_view&confID=100&abstract ID=60279.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr MS4-3.