Outcomes of SBRT for oligometastatic patients with lymph node metastases from gynaecological cancer.
PO-1419
Abstract
Outcomes of SBRT for oligometastatic patients with lymph node metastases from gynaecological cancer.
Authors: Giuseppe Facondo1, Gianluca Vullo1, Margherita Rotondi1, Riccardo Carlo Sigillo1, Vitaliana De Sanctis1, Maurizio Valeriani1, Mattia Falchetto Osti1
1Università degli Studi di Roma "La Sapienza", A.O.U Sant'Andrea M-P, Radiation Oncology, Rome, Italy
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Purpose or Objective
To evaluate the effect of stereotactic body radiation therapy (SBRT) on the clinical outcomes as a local treatment for lymph node metastases originating from gynecological cancer
Material and Methods
We retrospectively analyzed 29 lymph node metastases in 22 oligometastatic/oligoprogressive patients treated with ablative SBRT between November 2007 and October 2021 at our institution. SBRT was delivered by volumetric-modulated arc therapy (V-MAT) and Intensity-modulated radiation therapy (IMRT). All patients underwent image-guided radiotherapy (IGRT) using cone-beam computed tomography (CBCT) system as daily pre-treatment imaging. Follow-up was performed with a CT scan with contrast medium or FDG/PET-CT every three months for the first two years after SBRT and every six months afterwards. The primary endpoints were overall survival (OS), local control (LC) and progression free survival (PFS). Secondary endpoints were acute and late toxicities
Results
Median age was 61 years (range, 47– 87 years). Most common primary tumor was carcinoma of uterus (68.2%). Sixteen patients received systemic therapy before SBRT. The median Gross Tumor Volume (GTV) and the Planning Target Volume (PTV) were 5.7cm3(range 0.28-45.58 cm3) and 14.31 cm3 (range 1.61-100.35 cm3) respectively. Median SBRT dose was 36 Gy (range 23-60 Gy). Median dose per fraction was 10Gy (range 5-30 Gy). The median survival was 20 months and the actuarial 6-months, 1-year, 2-year and 5-year OS were 100%, 85.6%, 53.5% and 19.8% respectively. 6-months, 1-year, and 2-year LC was 93.1% ,87.9% and 79.8% respectively. 6-months, 1-year, and 2-year PFS were 60.7%, 45.5% and 11.4% respectively. Clinical response after SBRT evaluated using RECIST criteria revealed completed response in 18 lesions (62%) , partial response in 8 lesions (27.5%) , stable disease in 1 lesion (3.4%) and progressive disease in 2 lesions (6.8%). The 1-year and 2-year, OS for BED<70Gy vs BED>70Gy was 74.2%, and 31% vs 93%, and 72% respectively (CI 95% 0,1103 to 0,9091; 0.05 p-value). The 1-year and 2-year, OS for GTV<10 cm3 vs GTV>10 cm3 were 88% and 44% vs 80% and 68.6% respectively (CI 95% 0,3368 to 2,413; 0.84 p-value). Four patients experienced acute toxicities, mostly grade 1-2 of asthenia.
Conclusion
Despite the limited number of patients investigated in our study, SBRT is a feasible approach for lymph node recurrence, offering excellent in-field tumor control with low toxicity profile.