Hello and welcome. My name is Thibaut Thien. I'm a radiation oncologist at the Winship Cancer Institute of Emory University. On behalf of my co-authors, I'd like to thank the scientific committee for selecting this abstract, giving us the opportunity to share some of our institutional experience with lung SPRT for the treatment of oligoprogressive and oligo-recurrent metastatic disease. My disclosures are shown here. There's a growing clinical utilization of SPRT in the treatment of advanced lung cancers and lung metastases, especially in patients with limited progression. However, the role of lung SPRT in this setting is still not well defined. The purpose of this study was to determine the outcomes of patients with oligoprogressive and oligo-recurrent intrathoracic disease treated with SPRT. The study oligoprogression was defined as progression of five or fewer intrathoracic sites occurring in the presence of ongoing systemic therapy, while oligo-recurrence was defined similarly, but in the absence of ongoing systemic therapy. Survival was measured from time of clinical progression required treatment with SPRT until end of follow-up. 141 long SPRT courses were identified that met the above criteria, representing 118 patients with 172 target lesions. Characteristics of our patient population are summarized here. The median age at time of treatment was 63 years, and approximately half were male. The median follow-up for all patients was 2.2 years. The median interval from initial diagnosis to treatment for progression with long SPRT was 2.7 years. Approximately half of patients had a primary lung cancer, with the remainder distributed among other primary sites. Half were being treated with for oligoprogression, and half for oligo-recurrence. The majority of patients received a single long SPRT course, and the majority of courses treated a single target lesion. However, one single patient received four total long SPRT courses, and in one course, four lesions were targeted. Local control was excellent. As seen here, it was greater than 85% at five years. Median intrathoracic progression freeze for all freeze survival was nine months, at 40% at one year. Median overall survival was 40 months, with a small set of long-term survivors. Approximately 12% of patients were alive at five years. Patients received a median of two lines of systemic therapy at time of SPRT, of which 40% was in the form of immunotherapy. For patients treated with oligo-recurrence, i.e. those who were not actively receiving systemic therapy at time of progression, approximately half were able to remain off systemic therapy until end of follow-up, with a median duration of just under three years. For those who eventually required systemic therapy, the median delay until initiation was 10.7 months. For patients treated for oligo-progression, i.e. those who were actively receiving systemic agents, the majority, 70%, remain on the same agent after SPRT, with a minority going a planned switch in systemic agent immediately after SPRT, and also another minority that systemic therapy discontinued. This is a treatment plan from a representative case in which a patient with undifferentiated pleomorphic sarcoma, the extremity received SPRT, 12 gray times four, to two sites of progression in the left lung. The patient had developed lung metastases, which were previously treated with multiple thoracoscopic resections, and one prior lung SPRT course in which a single left-sided central legion was targeted. Our take-home messages are the following. Lung SPRT for the treatment of oligo-progressive and oligo-recurrent disease associated with durable control and for a subset of patients' long-term survival. Lung SPRT in the setting of oligo-progression and oligo-recurrence is a valuable complement to systemic therapy.

lung stereotactic radiation therapy

oligoprogressive

oligo-recurrent intrathoracic disease

local control

intrathoracic progression-free survival