Evaluating Optimal Timing of Endocrine Therapy and Radiation Therapy in Early-stage Breast Cancer (REaCT-RETT)

Ottawa Hospital Research Institute

Status and phase: Completed; Phase 4

Conditions: Early-stage Breast Cancer

Treatments: Combination Product: Endocrine Therapy and Radiotherapy

Study type: Interventional

Funder types: Other

Identifiers

NCT03948568

OTT 18-02

Details and patient eligibility

About

REaCT-RETT will demonstrate the non-inferiority of concurrent compared to sequential endocrine therapy in patients receiving post-operative radiotherapy for early stage breast cancer.

Full description

Clinical equipoise exists around the optimal time to start adjuvant endocrine therapy in patients who will receive post-operative radiotherapy for breast cancer. Patients receive either concurrent or sequential endocrine and radiation therapy, where concurrent therapy consists of endocrine therapy started before, with or during radiotherapy, while sequential treatment is defined as endocrine therapy starting after the completion of radiotherapy. A recent survey of Canadian oncologists showed that the main reason for prescribing sequential endocrine therapy was a concern that concurrent endocrine therapy and radiotherapy would worsen the toxicity of endocrine treatment. This is despite the absence of any clinical trial evidence to support this. Indeed, a recent systematic review by our group was unable to confirm or refute whether increased toxicities, related to the timing of endocrine therapy and radiotherapy actually exist in clinical practice. The investigators are therefore proposing a pragmatic randomised trial to assess whether or not concurrent endocrine therapy and radiotherapy worsens endocrine treatment-related symptoms in an era of modern endocrine and radiation therapy.

Enrollment: 262 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients with newly diagnosed early stage, hormone receptor positive breast cancer
• Planned to receive both endocrine therapy and post-operative radiotherapy
• Able to provide verbal consent

Exclusion criteria

• Previous endocrine therapy for invasive breast cancer
• Previous radiotherapy for breast cancer in the same breast

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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262 participants in 2 patient groups

Concurrent Endocrine Therapy and Radiotherapy

Active Comparator group

Description:

Concurrent endocrine therapy and radiotherapy. Concurrent endocrine therapy will be defined as, the commencement of endocrine therapy around 2 weeks before (a minimum of 1 week before to a maximum of 4 weeks) commencement of radiotherapy and continued throughout radiotherapy.

Treatment:

Combination Product: Endocrine Therapy and Radiotherapy

Sequential Endocrine Therapy after Radiotherapy

Active Comparator group

Description:

Sequential endocrine therapy after radiotherapy. Using the pragmatic definition sequential endocrine therapy should commence around 2 weeks (minimum 1 week, maximum 4 weeks) after the last fraction of radiotherapy.

Treatment:

Combination Product: Endocrine Therapy and Radiotherapy