259TiP - Treatment of Oligometastatic Breast Cancer (OMBC) - a randomised phase 3 trial comparing Stereotactic Ablative Radiotherapy (SABR) and systemic treatment with systemic treatment alone as first line treatment - TAORMINA

Background

The oligometastatic (OM) disease state with few metastases represents a specific entity between localised and disseminated cancer and has a superior outcome compared to patients with disseminated disease. Standard treatment for patients with OM breast cancer (OMBC) consists of systemic therapy. Several novel drugs have been implemented during the last decades but data show unchanged long-term prognosis for luminal and triple negative BC. Local treatment for patients with MBC is mainly used for symptomatic metastases. Stereotactic ablative body radiotherapy (SABR) delivers high doses with good therapeutic effects, low toxicity while sparing surrounding tissues. Published outcomes from 2 randomised phase II trials using SABR (COMET and NRG BR002) demonstrate contradicting results, suggesting a randomised trial in OMBC is needed.

Trial design

TAORMINA is an international, multicentre, randomised phase III trial for patients with OMBC, comparing systemic therapy alone (control arm) with systemic therapy combined with SABR toward all OM sites (investigational arm) as 1^st line therapy. The primary aim is to determine if the addition of SABR improves progression-free survival. Secondary endpoints are response rate, time to development of new lesions, safety, toxicity, quality of life and overall survival. In addition, the study aims to evaluate potential biomarkers of response and early progression. A total of 386 patients will be enrolled in at least 6 countries. Patients are randomised 2:1 (investigational vs control). A PET-CT is required before registering in the trial to ensure a maximum of 5 metastases restricted to 1-2 organs. SABR cannot be given before the 1st evaluation after 3 months showing at least stable disease. Patients with de novo OMBC shall complete planned (neo)adjuvant treatment including local treatment of the primary breast tumour. Patients are evaluated every 3^rd month for 3 years, every 6 months to five years and thereafter annually until 10 years or progression. Patients with progress are managed according to institutional practice and survival data are collected yearly.

Clinical trial identification

NCT05377047.

Legal entity responsible for the study

Västra Götalandsregionen, Department of Oncology/Swedish Association of Breast Oncologists (SABO).

Funding

1) The Swedish Research Council; 2) King Gustav V Jubilee Clinic Research Foundation at Sahlgrenska University Hospital.

Disclosure

All authors have declared no conflicts of interest.