This clinical research aims to determine if concurrent chemotherapy and radiation therapy is more effective than sequential chemotherapy and radiation therapy for patients with stage IIB-III breast cancer. It seeks to answer the following key questions:

1. When compared to sequential treatment, does concurrent chemoradiotherapy increase disease-free survival?
2. What effects does concurrent treatment have on post-operative look, quality of life, and side effects including arm swelling (lymphoedema)?
3. What are each treatment approach's financial costs?

Researchers will compare the following to groups:

Arm A: Participants in the sequential treatment group will first undergo chemotherapy and then radiation.

and Arm B: Participants in the concurrent treatment group will undergo radiation therapy while undergoing chemotherapy.

Participants are going to:

1. Get the usual chemotherapy (taxanes and/or anthracyclines).
2. Receive radiation therapy for three to four weeks.
3. Have follow-up visits every 6months for 5years to check for cancer recurrence, side effects, and quality of life.

Inclusion Criteria:

1. Pathologically confirmed invasive breast cancer
2. Stage IIB-III invasive breast cancer (AJCC 8th edition)
3. Patients planned for adjuvant chemotherapy and adjuvant radiotherapy
4. Patients fit to receive adjuvant chemotherapy and radiotherapy
5. Age > 18 years

Exclusion Criteria:

1. Hypersensitivity to taxanes
2. Patients receiving entire chemotherapy prior to surgery (neoadjuvant setting)
3. Unable or unwilling for regular follow up
4. Bilateral tumour needed RT to both sides
5. Patients planned for RT to oligometastatic sites
6. Unfavourable anatomical factors potentially leading to higher radiotherapy dose to heart and/or lungs (Exceeding the protocol specific mandatory dose constraints).
7. Pregnant patient