Radiotherapy After Chemoimmunotherapy in Urothelial Carcinoma

Key Takeaways

• In a single-center retrospective matched comparison, patients with locally advanced or metastatic urothelial carcinoma who received radiotherapy after first-line chemoimmunotherapy had longer PFS and OS than those who did not, an association that requires prospective validation.
• Response advantages were clearer before matching, but matched ORR and DOR differences were not statistically significant; interpretation is limited because response status (CR/PR) was one of the variables included in the propensity-score model.
• First-year local control favored radiotherapy, at 86.7% versus 23.1%, and 85.7% of symptomatic patients reported symptom relief after radiotherapy.
• Overall safety was comparable between groups, while multivariable analyses linked radiotherapy and treatment response with better outcomes and linked lung metastases, higher C-reactive protein, and liver metastases with worse outcomes.

Limited durability of first-line platinum-based chemoimmunotherapy and the burden of local progression remain persistent problems in locally advanced or metastatic urothelial carcinoma. Sequential radiotherapy has been explored as a way to intensify treatment after systemic therapy and before maintenance immunotherapy, particularly when pelvic disease, nodal sites, or other metastases continue to drive symptoms. In a single-center cohort from Chongqing, China, investigators compared that strategy with systemic treatment alone to ask whether survival, local control, and safety differed.

Investigators retrospectively evaluated patients treated at the First Affiliated Hospital of Chongqing Medical University from January 2017 through December 2024 in Qin et al. propensity score–matched analysis of radiotherapy added to first-line chemoimmunotherapy in locally advanced/metastatic urothelial carcinoma. Of 115 patients screened, 104 were evaluable, including 31 in the radiotherapy cohort and 73 in the non-radiotherapy cohort, and propensity score matching yielded 30 pairs. Both groups received platinum-based chemotherapy plus immune checkpoint inhibitors and then continued maintenance immunotherapy every 3 weeks for up to 35 cycles; the radiotherapy group additionally received radiotherapy within 2 to 4 weeks after the last chemotherapy cycle. Prespecified endpoints were objective response rate (ORR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and treatment-related adverse events, with imaging every 2 to 3 months and response assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.

In the matched comparison, median PFS was 18.70 versus 7.93 months with hazard ratio 0.44, 95% confidence interval 0.226–0.714, P=0.002, and median OS was 38.9 versus 19.8 months with hazard ratio 0.49, 95% confidence interval 0.239–0.929, P=0.031. Matched ORR and DOR differences were not significant. First-year local control was 86.7% with radiotherapy versus 23.1% without it. Treatment-related adverse events did not differ significantly between groups, no treatment-related deaths were reported, and radiotherapy-specific cystitis and enteritis were reported in the radiotherapy cohort.

Interpretation remains limited by the retrospective, single-center design, the eight-year enrollment period, and the possibility of residual confounding despite propensity score matching. Radiotherapy indications, target volumes, fractionation schedules, and prescribed doses varied across the cohort, and the small sample limited stratified analyses and biomarker interpretation. PD-L1 and HER2 testing were available in only a minority of patients, and the lack of significant matched differences in ORR and DOR leaves uncertainty about early response effects and about whether benefit varied by irradiation site or fractionation. In prognostic modeling, radiotherapy and objective response remained favorable factors, whereas lung metastases, higher C-reactive protein, and liver metastases were adverse factors.

In this Chongqing cohort, radiotherapy sequenced after first-line chemoimmunotherapy was associated with longer progression-free and overall survival, better local control, and an acceptable safety profile, according to the authors. They called for prospective validation.

Clinician Questions

Which patients were included in the radiotherapy plus chemoimmunotherapy comparison for locally advanced or metastatic urothelial carcinoma?

Eligible patients had histologically confirmed locally advanced or metastatic urothelial carcinoma, received first-line platinum-based chemotherapy plus immune checkpoint inhibitors, had an Eastern Cooperative Oncology Group performance status of 2 or lower and an estimated glomerular filtration rate of at least 60 mL/min, and were treated at a single center in Chongqing between 2017 and 2024. The comparison was between patients who went on to receive radiotherapy after first-line systemic therapy and those who did not.

How was radiotherapy delivered in the urothelial carcinoma cohort that received it after first-line systemic therapy?

Radiotherapy began 2 to 4 weeks after the last chemotherapy cycle, and maintenance immunotherapy resumed every 3 weeks. Treated sites included pelvic or bladder tumors, nodal disease, bone metastases, and one brain lesion, with fractionation ranging from 1.8 to 5 Gy per session and total doses ranging from 30 to 70 Gy. The study described this as a delivered practice pattern rather than a single standardized regimen.

What did the study identify as factors associated with better or worse PFS and OS in advanced urothelial carcinoma?

In multivariable modeling within this locally advanced or metastatic urothelial carcinoma cohort, radiotherapy and objective response to first-line treatment were associated with more favorable PFS and OS. Lung metastases and higher C-reactive protein were adverse factors for PFS, while liver metastases were adverse for OS. These findings were reported as observed prognostic associations within the cohort rather than as treatment directives.