The PROSPECTIVE trial aims to find out if using the results of Magnetic Resonance Imaging (MRI) for early breast cancer can select people to not have radiotherapy and still have a low chance of the cancer coming back after surgery.
The main question it aims to answer is:
\* Will cancer come back in the same breast as the original cancer in patients who have surgery for their breast cancer, but who don't have radiotherapy afterwards because the results of an MRI before surgery showed favourable characteristics for not having radiotherapy.
Has provided written, informed consent to participate in the study.
Female participants ≥ 50 years old with histologically* confirmed ER-positive and/or HER2-positive invasive breast cancer.
Has a life expectancy of at least 10 years and suitable for prolonged follow up for 10 years.
Breast imaging indicating unifocal, unilateral breast cancer must have been performed before pre-registration.
Triple negative breast cancer (ER-negative and PR-negative and HER2-negative) where ER and PR positivity is defined as ≥ 10% staining on IHC.
Previous invasive breast cancer and/or DCIS in either breast.
Prior RT to the breast or chest.
Participants who plan to have a mastectomy for the index cancer.
Parallel
Arm A: Radiotherapy Omission
RadiationOmission of radiotherapy based on pre-surgical MRI and pathology findings at surgery.
Arm B: Standard Treatment
Other interventionIneligible for RT omission on study; includes management of MRI-detected lesions.
Ipsilateral Invasive Recurrence Rate (IIRR) in low-risk patients omitting RT at a median of 5 years follow up
To determine the ipsilateral invasive recurrence rate (IIRR) in lower risk patients with unequivocally unifocal breast cancer and on breast MRI and favourable clinico-pathological features.
Ipsilateral Invasive Recurrence Rate (IIRR) in all participants omitting RT at a median of 10 years follow up after surgery.
To determine the ipsilateral invasive recurrence rate (IIRR) in patients allocated to omit radiotherapy (Arm A1).
IIRR in participants in Arm A1, Arm A2, Arm A, Arm B, and Arms A+B.
To determine the ipsilateral invasive recurrence rate (IIRR) in participants in Arm A2, Arm A, Arm B, and Arms A+B.
Ipsilateral DCIS recurrence rate in participants in Arm A1, Arm A2, Arm A, Arm B, and Arms A+B.
To determine the ipsilateral DCIS rate in the breast in participants in Arm A1, Arm A2, Arm A, Arm B, and Arms A+B.
The combined ipsilateral DCIS and invasive recurrence rate (IRR) in participants in Arm A1, Arm A2, Arm A, Arm B, and Arms A+B.
To determine the combined ipsilateral DCIS and invasive recurrence rate (IRR) in the breast in participants in Arm A1, Arm A2, Arm A, Arm B, and Arms A+B.
ET: Oncologic outcomes in relation to intensity of endocrine therapy (ET)
To analyse oncological outcomes in relation to the intensity of endocrine therapy (ET) (no ET, less than 2 years ET, 2-5 years ET, more than 5 years ET).
Endocrine Therapy: Adherence to ET
ET side effects as measured with the FACT-ES.
Radiology: Outcomes of MRI
Outcomes of MRI in those patients who have MRI post-registration measured by BPR, occult lesion rate, biopsy approach, result of biopsy, malignant occult lesion rate.
Radiology: Occult lesion and malignant occult lesion detection rate
To number of occult lesions and malignant occult lesions detected on pre-operative MRI per institution
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