Summary

This randomized phase III trial studies lymph node dissection and radiation therapy to see how well it works compared to radiation therapy alone in treating patients with breast cancer previously treated with chemotherapy and surgery. Lymph node dissection may remove cancer cells that have spread to nearby lymph nodes in patients with breast cancer. Radiation therapy uses high-energy x rays or protons to kill tumor cells. It is not yet known if radiation therapy works better alone or with lymph node dissection in treating patients with breast cancer previously treated with chemotherapy and surgery.

Objectives

PRIMARY OBJECTIVE:
I. To evaluate whether radiation to the undissected axilla and regional lymph nodes is not inferior to axillary lymph node dissection with radiation to the regional lymph nodes but not to the dissected axilla in terms of invasive breast cancer recurrence-free interval in patients with positive sentinel lymph node(s) (SLN[s]) after completion of neoadjuvant chemotherapy.

SECONDARY OBJECTIVES:
I. To evaluate whether radiation to the undissected axilla and regional lymph nodes is not inferior to axillary lymph node dissection with radiation to the regional lymph nodes but not to the dissected axilla in terms of the incidence of invasive loco-regional recurrences in patients with a positive SLN(s) after completion of neoadjuvant chemotherapy.
II. To obtain an estimate of the distribution of residual disease burden scores.
III. To estimate the distribution of overall survival.

CORRELATIVE OBJECTIVES:
I. To estimate the incidence of arm lymphedema.
II. To estimate the incidence of breast lymphedema for patients who underwent breast conserving surgery based on the specific treatment rendered to the axilla.

OUTLINE: Patients are randomized to 1 of 2 treatment arms.

ARM I: Patients undergo axillary lymph node dissection. Beginning 3-12 weeks following surgery, patients undergo nodal radiation therapy comprising 3-dimensional (3D) conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or proton radiation therapy (PRT) 5 days a week for 5-6 weeks. Patients also undergo collection of blood on study.

ARM II: Patients undergo axillary and nodal radiation therapy comprising 3D-CRT, IMRT, or PRT 5 days a week for 5-6 weeks. Patients also undergo collection of blood on study.

After completion of study treatment, patients are followed up at least every 6 months for years 1-2 and then annually for years 3-8.