NCT05417516

A Randomized Trial of Five Fraction Partial Breast Irradiation (RAPID2)

A Randomized Trial of Five-Fraction Partial Breast Irradiation (RAPID2)

• Status: Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 910 (estimated)
• Sponsor: Ontario Clinical Oncology Group (OCOG) · Academic / Other
• Sex: Female
• Age: 50 Years – 120 Years
• Healthy volunteers: Not accepted

Summary

The primary objective of this study is to determine in women with node negative BC ≤3cm in size, if PBI compared to WBI, both given once-a-day over 1 week following BCS, is non-inferior for LR and reduces adverse cosmesis. The primary outcomes are LR and patient-assessed cosmesis at 3 years post randomization.

Detailed description

This is a randomized, two-arm, single blinded trial comparing two radiation treatment modalities, PBI and WBI. Following BCS or on the completion of additional adjuvant chemotherapy, eligible and consenting patients with newly diagnosed and histologically confirmed invasive carcinoma of the breast (without evidence of metastatic disease); with microscopically clear resection margins of 1mm (or no residual disease on re-excision) and negative axillary node involvement will be randomized in a 1:1 fashion to receive either PBI (experimental group) or WBI (control group). Study participants will receive 26Gy in 5 fractions in both treatment arms, treated once per day, for a period of 5-7 days. Study participants will not be made aware of treatment allocation to prevent any potential bias in their assessment of cosmesis. Stratification factors include tumour size, estrogen receptor (ER) status, and clinical centre.

Conditions

• Breast Neoplasm Female
• Radiotherapy
• Cosmetic Outcome

Interventions

Type	Name	Description
RADIATION	Whole Breast Irradiation (WBI)	The dose fractionation and prescription is 26Gy in 5 fractions to the PTV once per day over 5-7 days (due to holiday weekends up to 8 days will be acceptable).
RADIATION	Partial Breast Irradiation (PBI)	The dose fractionation and prescription is 26Gy in 5 fractions to the PTV prescribed at the isocentre of the treatment fields treated once per day over 5-7 days (due to holiday weekends up to 8 days will be acceptable).

Timeline

• Start date: 2023-11-20
• Primary completion: 2029-11-01
• Completion: 2031-11-01
• First posted: 2022-06-14
• Last updated: 2026-04-13

Locations

28 sites across 2 countries: Australia, Canada