ESTRO 2024 - Abstract Book

S722

Clinical - Breast

ESTRO 2024

Keywords: neoadjuvant chemotherapy, time to RT, pCR

References:

Silva SB, Pereira AAl, Marta GN et al. Clinical impact of adjuvant radiation therapy delay after neoadjuvant chemotherapy in locally advanced breast cancer.

3193

Digital Poster

STEREOTACTIC ABLATIVE RADIOTHERAPY: A PROMISING CHANCE FOR OLIGOMETASTATIC BREAST CANCER PATIENTS.

Paola Anselmo 1 , Fabio Arcidiacono 1 , Michelina Casale 1 , Martina Nunzi 2 , Silvia Sabatini 2 , Jenifer Foglietta 2 , Marco Italiani 1 , Fabio Trippa 1 1 Radiotherapy Oncology Centre S.Maria Hospital, Oncology, Terni, Italy. 2 Medical Oncology S.Maria Hospital, Oncology, Terni, Italy

Purpose/Objective:

Multidisciplinary management of oligometastatic (oligo-M) breast cancer (BC) with local therapy could improve disease control and defer systemic treatment, therefore stereotactic ablative radiotherapy (SAbR) may improve the prognosis of oligo-M BC patients. In the literature, there is very little data available that is specific to breast cancer.

Material/Methods:

We conducted a monoistitutional retrospective analysis on oligo-M BC patients treated with LINAC-based SAbR in combination with systemic medical treatment. The primary objective was to estimate local control and toxicity of the combined approach.

Results:

35 patients with 50 oligo-M BC (less than 5 lesions in the same organs with maximum diameter <5cm) were irradiated from June 2015 to February 2023. Median age and KPS were 60 years (35-84) and 100% (90-100), respectively. The patients mostly had one to four lesion(s) whose most widely represented site was bone (34/68%), lymph nodes (10/20%), lung (4/8%) and liver (2/4%). The primary tumor expressed estrogen receptors in 27 patients (77%); the status was HER2+++ in 7 patients (20%). All patients were studied with PET/TC before SAbR and during follow-up to detect oligoprogression. 33 (94%) patients developed metastasis during active systemic therapy (oligo progressive patients), while 2 (6%) developed metastasis without an active treatment (oligo-recurrent patients). The