Postmastectomy radiotherapy (PMRT) is unequivocally beneficial in reducing the recurrences as well as improving survival in node positive breast cancer patients. PMRT for women with T1-T2 tumors and negative axillary nodes is not generally warranted because of the presumed low risk of recurrence in this population as a whole. However, in the setting of multiple adverse prognostic factors, the recurrence risk approaches and in some cases surpasses the risk of recurrence documented for patients with one to three positive lymph nodes. Numerous retrospective series have reported the outcome and patterns of failure for post-mastectomy patients treated without radiation. Many of these series have analyzed several high risk factors which were predictive of loco-regional recurrence wherein the role of adjuvant post-mastectomy radiation can be considered. Some authors have used combinations of prognostic factors, such as age, tumour size, grade, receptor status, Her2neu status and lympho-vascular space invasion to define subgroups with more specific risks of loco-regional recurrence than single factors alone. The current trial hypothesizes that "Post-mastectomy radiation in high risk, node negative early breast cancer patients decreases rates of loco-regional recurrence and improves disease free survival" and propose to address the question in randomized setting.

Inclusion Criteria:

• Women with unilateral pT1,2N0M0 breast cancer or multifocal breast cancer if largest discrete tumour at least 2cm or if the tumour area comprises multiple small adjacent foci of invasive carcinoma then overall maximum dimension taken. This must be greater than 2cm.
• Upfront total mastectomy (with minimum 1 mm margin clear of invasive cancer or DCIS) and axillary staging procedure (clearance, sampling or SNB)
• T2 tumors with one risk factor or T1 tumors with any of the following two high risk factors such as presence of high grade, lymphovascular invasion, ER/PR negative, HER2 positivity, age < 35 years.
• Fit to receive adjuvant radiation +/- chemotherapy (if indicated) +/- hormonal therapy (if indicated)
• Written, informed consent

Exclusion Criteria:

• Any pTis/3/4, M1 patients
• Patients who have any pathologically involved axillary nodes (micro-metastasis may be allowed)
• Patients who have undergone neoadjuvant systemic therapy.
• Previous or concurrent malignancy other than non melanomatous skin cancer and carcinoma in situ of the cervix
• Pregnancy
• Bilateral breast cancer
• Not fit for surgery, radiotherapy or adjuvant systemic therapy
• Unable or unwilling to give informed consent