HYPofractionated Adjuvant RadioTherapy in 1 Versus 2 Weeks in High-risk Patients With Breast Cancer (HYPART).

We at PGIMER have been practicing hypofractionated radiotherapy in breast cancer patients for the last 4 decades. Our standard doses have been 35Gy/15#/3wks to the chest wall after mastectomy and 40Gy/16#/3wks after breast conserving surgery (BCS).It is also a routine practice in the UK and in a few centers in Canada. Hypofractionation reduces treatment time to half while maintaining cosmesis and gives control rates equal to conventional fractionation. As breast cancer is a leading cancer in females and radiation therapy is an important part of its local management, hypofractionation helps radiation centers worldwide to meet the growing need for radiation treatment in breast cancer, particularly in developing countries where resources are limited. It also reduces the financial burden on the patient and family. In this study we want to evaluate the impact of reducing the treatment duration from 3 weeks to 1 week. Eligible patients with breast cancer after mastectomy or BCS will be treated with a radiotherapy dose of 26Gy in 5 fractions over 1 week in the study arm and 40Gy in 15 fractions over 2 weeks in the control arm. The primary endpoint of this noninferiority study will be locoregional tumour control. Secondary endpoints will be early and late radiation toxicities, quality of life, contralateral primary tumours, regional and distant metastases, survival and second cancers. A total of 1018 patients will be randomised (1:1) to receive 1 week or 2 weeks of radiotherapy. An event-driven analysis will be performed after at least 94 patients have documented locoregional recurrences.

Sex

Female

Minimum age

18 Years

Inclusion Criteria:

1. Age ≥18 years
2. Female or male
3. Invasive carcinoma of the breast
4. Breast conserving surgery(BCS) with axillary clearance or total mastectomy with axillary clearance(TMAC); (reconstruction allowed but not with implant; tissue expanders with distant metal ports are allowed)
5. Concurrent trastuzumab and hormone therapy is allowed
6. Axillary staging and/or dissection
7. Complete microscopic excision of primary tumour
8. pT3-4pN2-3 M0 disease
9. Clinical stage III disease or pathological node positive if they have received neo-adjuvant chemotherapy.
10. Written informed consent
11. Able to comply with follow-up

Exclusion Criteria:

1. Supraclavicular node or internal mammary node or distant metastasis
2. Past history of malignancy except (i) basal cell skin cancer and CIN cervix uteri or(ii) non-breast malignancy allowed if treated with curative intent and at least 5 years disease free
3. Contralateral breast cancer, including DCIS, irrespective of date of diagnosis
4. Breast reconstruction using implants
5. Pregnancy
6. Concurrent cytotoxic chemotherapy(sequential neoadjuvant or adjuvant cytotoxic therapy allowed)

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• BACKGROUNDYadav BS, Sharma SC, Singh R, Singh G. Patterns of relapse in locally advanced breast cancer treated with neoadjuvant chemotherapy followed by surgery and radiotherapy. J Cancer Res Ther. 2007 Apr-Jun;3(2):75-80. doi: 10.4103/0973-1482.34683. PMID 17998727
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• DERIVEDYadav BS, Goyal S, Dahiya D, Vias P, Gupta A, Datta A, Kataria V, Singh NR, Sharma R, Laroiya I, Irrinki S, P K, Pandey A. HYPofractionated Adjuvant RadioTherapy in 1 Versus 2 Weeks in High-Risk Patients With Breast Cancer (HYPART): Acute Toxicity Results. Int J Radiat Oncol Biol Phys. 2026 Jan 1;124(1):133-146. doi: 10.1016/j.ijrobp.2025.07.1447. Epub 2025 Aug 6. PMID 40780546
• DERIVEDYadav BS, Dahiya D, Kannan P, Goyal S, Laroiya I, Irrinki S, Singh NR, Sharma R. HYPofractionated Adjuvant RadioTherapy in 1 versus 2 weeks in high-risk patients with breast cancer (HYPART): a non-inferiority, open-label, phase III randomised trial. Trials. 2024 Jan 2;25(1):21. doi: 10.1186/s13063-023-07851-7. PMID 38167339