Research has shown that treatment with conventional radiation techniques and chemotherapy following mastectomy or breast conserving surgery has resulted in better rates of locoregional control and overall survival in stage IIB-III breast cancer. The current feasibility trial using the most recent advance in radiation therapy, namely helical tomotherapy intensity modulated radiation therapy (HT-IMRT), hopes to improve on the results of conventional radiation by decreasing the amount of radiation-induced toxicity in patients with stage IIb-III breast cancer.

The role of locoregional radiation therapy in the management of stage IIB and III breast cancer has evolved and continues to evolve. The exact role of locoregional radiation, including axillary, supraclavicular and internal mammary nodes is, however, not clear. Radiation-induced toxicity remains a limiting factor to expanding the indications for radiation therapy to axillary and internal mammary nodes in the treatment of stage IIB and III breast cancer. Excellent target coverage and normal tissue sparing of IMRT has been previously demonstrated dosimetrically and clinically. In this feasibility study, patients will receive 50 Gy of radiation therapy in 25 fractions to the chest wall and supraclavicular, axillary and IM nodal areas using HT-IMRT following breast conserving surgery or mastectomy and chemotherapy. Patients will also be eligible for a radiation boost to 12 Gy by HT-IMRT or HDR brachytherapy. It is expected that treatment with HT-IMRT will result in appreciably fewer side-effects following locoregional irradiation due to a reduction in normal tissue irradiation, as compared to conventional radiation therapy.

Inclusion Criteria:

1. Surgery with either mastectomy or breast conserving surgery
2. Presence and association of any of the following high risk pathological features present at time of surgery: stage pT3-4 and pN0 and central/medial location of tumour or any pT and pN2 (stage IIB-stage III)
3. All patients will have been treated previously with chemotherapy prior to radiation therapy
4. ECOG performance status of 2 or less

Exclusion Criteria:

1. Prior chest wall/breast or nodal radiation for other malignancies (i.e. Hodgkin disease)
2. HER2+ positive patients
3. Patients with diagnosis of metastatic disease
4. Prior or active malignancy except non-melanoma skin carcinoma within 5 years of the diagnosis of breast cancer