3242 - Multi-Institutional Analysis of Extracranial Oligometastatic Bladder Cancer Patients Treated with Stereotactic Body Radiotherapy

12:45pm - 02:00pm PT

Hall F

Screen: 1

POSTER

Presenter(s)

Ozan Cem Guler, MD - Baskent University, Adana, Adana

O. C. C. Guler¹, P. Hurmuz², B. Demirhan³, A. Elmali⁴, Y. Özyürek⁵, G. Ozyigit⁵, and H. C. Onal⁶; ¹Baskent University Faculty of Medicine, Department of Radiation Oncology, Adana, Turkey, ²Hacettepe University Department of Radiation Oncology, Ankara, Turkey, ³Iskenderun Gelisim Hospital, Hatay, Turkey, ⁴Hacettepe University, Faculty of Medicine, Department of Radiation Oncology, Ankara, Turkey, ⁵Hacettepe University Faculty of Medicine, Department of Radiation Oncology, Ankara, Turkey, ⁶Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana, Turkey

Purpose/Objective(s):

To investigate the treatment outcomes of extracranial oligometastatic bladder cancer patients treated with stereotactic body radiotherapy (SBRT).

Materials/Methods:

The clinical data of 39 extra-cranial oligometastatic bladder cancer (= 5 lesions) patients and 62 lesions treated with SBRT at three cancer institutions were retrospectively analyzed. The prognostic factors predicting overall survival (OS), distant metastasis-free survival (DMFS), and local control (LC) were assessed in uni- and multivariable analyses.

Results:

The median age was 65 years (range, 40-81 years). The majority of the patients (82%) received surgery and chemoradiotherapy (Trimodality therapy) for their primary tumor. 29 patients (74.4%) were staged with flouro-deoxyglucose positron emission tomography (FDG-PET/CT) (74.4%) and most common metastatic site was bone (71.9%). 22 patients (56.4%) had single lesion. The median total radiation dose was 27 Gy (range: 16 – 60 Gy) delivered in a median of 3 fractions (range: 1 – 5). The median follow-up time for the entire cohort was 93.2 months (interquartile range: 65.1 – 121.2 months). The 2-year OS, DMFS, and LC rates were 55.8%, 55.1%, and 91.5%, respectively. Median time for oligometastasis was 9.5 months (range: 0-66.9 months). The 2-year DMFS rate was significantly higher in patients developing oligometastasis >12 months than those developing oligometastasis =12 months (20.5% vs. 84.2%; p = 0.02). OS and LC did not differ for such patients. Metastasis number (1 vs. >1) had no impact on OS, DMFS or LC.

Conclusion:

In this multi-center study, we demonstrated that SBRT is an effective treatment option of metastatic lesions in oligometastatic bladder cancer patients by providing promising LC rates. Early development of oligometastasis <12 months was associated with worse outcomes.