ESTRO 2023 - Abstract Book

S36

Saturday 13 May

ESTRO 2023

Figure 2. Kaplan-Meier curve of (A) Local Progression Free Survival (LPFS) and (B) Distant Free Survival (DFS)

PD-0069 Anatomic pattern of recurrence after single or multifraction SBRT for lymph nodal lesions. M. Ferro 1,1 , G. Macchia 1 , D. Pezzulla 1 , S. Cilla 2 , C. Romano 2 , M. Boccardi 1 , P. Bonome 1 , V. Picardi 1 , S. Cammelli 3,4 , M. Buwenge 3 , A.G. Morganti 3,4 , F. Deodato 1,5 1 Gemelli Molise Hospital – Università Cattolica del Sacro Cuore, Radiation Oncology Unit, Campobasso, Italy; 2 Gemelli Molise Hospital – Università Cattolica del Sacro Cuore, Medical Physics Unit, Campobasso, Italy; 3 IRCCS Azienda Ospedaliero-Universitaria di Bologna, Radiation Oncology, Bologna, Italy; 4 Alma Mater Studiorum Bologna University, Department of Experimental, Diagnostic, and Specialty Medicine - DIMES, Bologna, Italy; 5 Università Cattolica del Sacro Cuore, Istituto di Radiologia, Roma, Italy Purpose or Objective Single (SRS) or multi-fraction Stereotactic Body RadioTherapy (SBRT) are effective treatment options for the treatment of oligometastatic disease of lymph nodes. Despite the encouraging local control rate, progression-free survival remains unfair due to relapses that might occur in the same district or at other sites. The recurrence pattern analysis after nodal SRS/SBRT in oligometastatic patients could pave the way for different strategies of therapeutic intensification. Materials and Methods This retrospective trial looks into the patterns of failure in patients with nodal metastases who were enrolled and treated with SBRT (DESTROY-1) or SRS (DESTROY-2) in 2 prospective trials at our Institution. We documented the various relapse locations of the involved lymph nodes that had been irradiated with a previous RT dose of 20 to 50 Gy in five daily fractions or 12 to 24 Gy single fraction treatment. Results Data on 190 patients who received SBRT or SRS on 269 nodal lesions were reviewed. The male/female ratio was 94/96 and the median age was 66 years (range: 30-89). The most represented primary cancer was the gynaecological one (34.6%), followed by genitourinary cancer (26.7%). Pathologic lymph nodes were most frequently located in the pelvis (35.7%), followed by the thorax (34.6%) and the abdomen (24.9%) (Table 1). After SBRT/SRS the recurrences were diagnosed at imaging with a median distant metastasis-free survival (DMFS) time of 17 months (range: 3-184 months). The pattern of failure was loco-regional in 66 (42.6%) and distant in 89 (57.4%) patients, respectively. Among patients with loco-regional