Standard or Comprehensive Radiation Therapy in Treating Patients With Early-Stage Breast Cancer Previously Treated With Chemotherapy and Surgery

PRIMARY OBJECTIVES: To evaluate whether the addition of chest wall + regional nodal radiation therapy (XRT) after mastectomy or breast + regional nodal XRT after breast conserving surgery will significantly reduce the rate of events for invasive breast cancer recurrence-free interval (IBC-RFI) in patients who present with histologically positive axillary nodes but convert to histologically negative axillary nodes following neoadjuvant chemotherapy. SECONDARY OBJECTIVES: I. To evaluate whether the addition of chest wall + regional nodal XRT after mastectomy or breast + regional nodal XRT after breast conserving surgery will significantly prolong overall survival (OS) in patients who present with histologically positive axillary nodes but convert to histologically negative axillary nodes following neoadjuvant chemotherapy. II. To evaluate whether the addition of chest wall + regional nodal XRT after mastectomy or breast + regional nodal XRT after breast conserving surgery will significantly reduce the rates of events for local-regional recurrence-free interval (LRRFI) in patients who present with histologically positive axillary nodes but convert to histologically negative axillary nodes following neoadjuvant chemotherapy. III. To evaluate whether the addition of chest wall + regional nodal XRT after mastectomy or breast + regional nodal XRT after breast conserving surgery will significantly reduce the rate of events for distant recurrence-free interval (DRFI) in patients who present with histologically positive axillary nodes but convert to histologically negative axillary nodes following neoadjuvant chemotherapy. IV. To compare the rates of disease-free survival (DFS)-ductal carcinoma in situ (DCIS) by treatment arm. V. To compare the rates of second primary cancer (SPC) by treatment arm. VI. To compare the effect of adding XRT on the cosmetic outcomes in mastectomy patients who have had reconstruction. VII. To compare the effect of adding XRT on quality of life including arm problems, lymphedema, pain, and fatigue. VIII. To evaluate the toxicity associated with each of the radiation therapy regimens. IX. To determine whether computed tomography (CT)-based conformal methods (intensity-modulated radiation therapy \[IMRT\] and 3-dimensional conformal radiation therapy \[3DCRT\]) for chestwall + regional nodal XRT post mastectomy and regional nodal XRT with breast XRT following breast conserving surgery are feasible in a multi-institutional setting and whether dose-volume analyses can be established to assess treatment adequacy and to develop normal tissue complication probabilities (NTCP) for the likelihood of toxicity. X. To compare the effect of XRT in patients receiving mastectomy and in patients receiving lumpectomy. XI. To examine the role of proliferation measures as a prognosticator for patients with residual disease after neoadjuvant chemotherapy. XII. To develop predictors of the degree of reduction in local regional recurrence (LRR). OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM 1: Patients are assigned to 1 of 2 treatment groups. GROUP 1A: Lumpectomy patients undergo whole breast radiation therapy using IMRT or 3DCRT once daily 5 days a week for 5 weeks followed by a radiation therapy boost to the lumpectomy cavity once daily 5 days a week for 1-1/2 weeks. GROUP 1B: Mastectomy patients do not undergo radiation therapy. ARM 2: Patients are assigned to 1 of 2 treatment groups. GROUP 2A: Lumpectomy patients undergo regional nodal radiation therapy with whole breast radiation therapy using IMRT or 3DCRT once daily 5 days a week for 5 weeks followed by a radiation therapy boost to the lumpectomy cavity once daily 5 days a week for 1-1/2 weeks. GROUP 2B: Mastectomy patients undergo regional nodal radiation therapy and chestwall XRT using IMRT or 3DCRT once daily 5 days a week for 5 weeks. All patients also receive systemic therapy as planned (hormonal therapy for patients with hormone-receptor positive breast cancer and trastuzumab or other anti-human epidermal growth factor receptor 2 \[HER2\] therapy for patients with breast cancer that is HER2-positive). After completion of study treatment, patients are followed up at 6, 12, 18, and 24 months and then yearly for 8 years.