2383P - Stereotactic body radiotherapy (SBRT) of patients with oligometastatic urothelial cancer (UC): A single institution experience

Background

Standard of care for treatment-naïve patients with metastatic UC is platinum-based combination chemotherapy followed by maintenance avelumab if disease stabilisation or response is achieved. The best strategy to treat patients with oligometastatic disease is unknown; data on side effects and benefit of SBRT in postponing or avoiding systemic treatments in UC is limited.

Methods

We performed a real-world study to explore local control rate (LCR), progression-free survival (PFS), overall survival (OS) and tolerability of SBRT of all available patients with metastatic UC treated at Karolinska University Hospital between 2009 and 2022 (n=41). Baseline clinical characteristics and treatment outcome data were collected from medical records. Radiological examinations were reviewed by a radiologist, from baseline until progressive disease.

Results

In our cohort 78% of patients were male, the median age was 72 yr (range 54-88) and all patients had performance status 0-2 (0:54%, 1:39%, 2:7%). Most patients had a primary UC in the bladder (66%) and 24% had metastatic disease at diagnosis. The most common location of metastases receiving SBRT were lungs (44%) and lymph nodes (27%). The number of metastatic sites receiving SBRT were 1, 2 and 3 in 73%, 24% and 2% of patients, respectively. Most patients (90%) achieved local control. The PFS and OS for the complete cohort were 4,4 and 26,2 months, respectively. The only clinical factor significantly associated with favourable outcome was the number of metastases, i.e., ≤2 vs > 2 (p = 0.049). Only one patient did not complete the planned SBRT (treatment related pain). We found 13 patients (32 %) with OS exceeding 3 years and 6 out of these 13 patients never received systemic treatment after SBRT. A total of 11 patients are still alive, but 4 of these patients have follow-up (FU) shorter than 3 years (16-29 months FU).

Conclusions

In summary, SBRT in UC is associated with high LCR and is well tolerated. Selected patients may achieve long survival, postponing or avoiding systemic treatment. A randomized study to investigate the role of SBRT in this population is warranted.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Region Stockholm, Karolinska University Hospital.

Funding

This work was supported by the Swedish Cancer Society [grant agreements CAN 2016/391, CAN 2016/393, CAN (221995PJ), CAN (221996Fk), 190171, 190288], the King Gustav V Jubilee Fund [grant agreements #174303 and #204163 ]; the Stockholm County Council [grant agreements #20160051, #20180022 and 20200068].

Disclosure

F. Jawdat: Financial Interests, Personal, Advisory Board: MSD, Astellas; Non-Financial Interests, Member: Swedish Union for Uro-oncology; Non-Financial Interests, Member: Swedish Society of Oncology. F. Costa Svedman: Financial Interests, Institutional, Other, Expert panel: Pfizer; Financial Interests, Institutional, Other, Organizing and participating in educational events: BMS; Financial Interests, Institutional, Other, Participation is a preceptorship with travel grants: Merck; Financial Interests, Institutional, Local PI: Eisai, Idera, Merck; Financial Interests, Institutional, Coordinating PI: Merck; Non-Financial Interests, Member: Swedish Union for Uro-oncology; Non-Financial Interests, Member: Swedish Society of Oncology. K. Holmsten: Non-Financial Interests, Member: Swedish Union for Uro-oncology; Non-Financial Interests, Leadership Role: NUCOG, Nordic Urthelial Cancer Oncology Group. A. Ullén: Financial Interests, Personal, Advisory Board, AdBoard: Astellas Pharma, Merck KGaA; Financial Interests, Institutional, Research Grant, Research funding for RWD study on Avelumab: Merck; Financial Interests, Institutional, Research Grant, Research funding, RWD study on Ra223: Bayer AB; Financial Interests, Institutional, Coordinating PI, TROPICS-02: Gilead; Financial Interests, Institutional, Coordinating PI, KN-905: MSD/Merck; Financial Interests, Institutional, Coordinating PI, Javelin Bladder100: Merck KGaA; Non-Financial Interests, Leadership Role, Steering Committee Member and Chair for Advanced bladder cancer section: Swedish Society for Urological Oncology; Non-Financial Interests, Member: Swedish Society for Oncology; Non-Financial Interests, Leadership Role, Co-chair: Nordic Urothelial Cancer Oncology Group. All other authors have declared no conflicts of interest.