Case Report: Serial stereotactic radiotherapy in lieu of systemic therapy change for oligoprogressive breast cancer: eight courses to 17 metastases.

Stereotactic ablative body radiotherapy (SABR) is emerging as a strategy for treating oligoprogressive disease in lieu of changing systemic therapy. We report the case of a patient with oligoprogressive breast cancer who received seven sequential rounds of SABR and one course of stereotactic radiosurgery to 17 metastases over 5 years, delaying a change in systemic therapy on eight occasions. The patient's age, performance status, and treatment preferences guided this unique treatment journey, emphasising quality of life. In limited trials, SABR has not demonstrated improvement in overall survival. Nevertheless, early evidence, including this case of oligoprogression, supports its role in delaying systemic therapy.