Early Bone Metastases are Associated with Worse Outcomes in Metastatic Urothelial Carcinoma

New prognostic model in patients with advanced urothelial carcinoma treated with second-line immune checkpoint inhibitors

BACKGROUND

Bellmunt Risk Score, based on Eastern Cooperative Oncology Group (ECOG) performance status (PS), hemoglobin levels and presence of liver metastases, is the most established prognostic algorithm for patients with advanced urothelial cancer (aUC) progressing after platinum-based chemotherapy. Nevertheless, existing algorithms may not be sufficient following the introduction of immunotherapy. Our aim was to develop an improved prognostic model in patients receiving second-line atezolizumab for aUC.

METHODS

Patients with aUC progressing after cisplatin/carboplatin-based chemotherapy and enrolled in the prospective, single-arm, phase IIIb SAUL study were included in this analysis. Patients were treated with 3-weekly atezolizumab 1200 mg intravenously. The development and internal validation of a prognostic model for overall survival (OS) was performed using Cox regression analyses, bootstrapping methods and calibration.

RESULTS

In 936 patients, ECOG PS, alkaline phosphatase, hemoglobin, neutrophil-to-lymphocyte ratio, liver metastases, bone metastases and time from last chemotherapy were identified as independent prognostic factors. In a 4-tier model, median OS for patients with 0-1, 2, 3-4 and 5-7 risk factors was 18.6, 10.4, 4.8 and 2.1 months, respectively. Compared with Bellmunt Risk Score, this model provided enhanced prognostic separation, with a c-index of 0.725 vs 0.685 and increment in c-statistic of 0.04 (p<0.001). Inclusion of PD-L1 expression did not improve the model.

CONCLUSIONS

We developed and internally validated a prognostic model for patients with aUC receiving postplatinum immunotherapy. This model represents an improvement over the Bellmunt algorithm and could aid selection of patients with aUC for second-line immunotherapy.

TRIAL REGISTRATION NUMBER

NCT02928406.

Association Between Sites of Metastasis and Outcomes With Immune Checkpoint Inhibitors in Advanced Urothelial Carcinoma

BACKGROUND

Sites of metastasis have prognostic significance in advanced urothelial carcinoma (aUC), but more information is needed regarding outcomes based on metastatic sites in patients treated with immune checkpoint inhibitors (ICI). We hypothesized that presence of liver/bone metastases would be associated with worse outcomes with ICI.

METHODS

We identified a retrospective cohort of patients with aUC across 26 institutions, collecting demographics, clinicopathological, treatment, and outcomes information. Outcomes were compared with logistic (observed response rate; ORR) and Cox (progression-free survival; PFS, overall survival; OS) regression between patients with/without metastasis beyond lymph nodes (LN) and those with/without bone/liver/lung metastasis. Analysis was stratified by 1st or 2nd+ line.

RESULTS

We identified 917 ICI-treated patients: in the 1st line, bone/liver metastases were associated with shorter PFS (Hazard ratio; HR: 1.65 and 2.54), OS (HR: 1.60 and 2.35, respectively) and lower ORR (OR: 0.48 and 0.31). In the 2nd+ line, bone/liver metastases were associated with shorter PFS (HR: 1.71 and 1.62), OS (HR: 1.76 and 1.56) and, for bone-only metastases, lower ORR (OR: 0.29). In the 1st line, LN-confined metastasis was associated with longer PFS (HR: 0.53), OS (HR:0.49) and higher ORR (OR: 2.97). In the 2nd+ line, LN-confined metastasis was associated with longer PFS (HR: 0.47), OS (HR: 0.54), and higher ORR (OR: 2.79); all associations were significant.

CONCLUSION

Bone and/or liver metastases were associated with worse, while LN-confined metastases were associated with better outcomes in patients with aUC receiving ICI. These findings in a large population treated outside clinical trials corroborate data from trial subset analyses.

The prognostic impact of bone metastasis in patients with metastatic urothelial carcinoma treated with first-line platinum-based chemotherapy

Background:

In metastatic urothelial cancer (mUC), bone metastasis (BM) are associated with significant morbidity and mortality, yet their role as an independent prognostic variable remains unclear. We aimed to determine the impact of BM on overall survival (OS) in patients with mUC treated with first-line platinum-based chemotherapy (PBC).

Methods:

mUC patients receiving PBC at the Princess Margaret Cancer Center, Tom Baker Cancer Center, or Cross Cancer Institute from January 2005 to January 2018 were identified retrospectively using central pharmacy database records. Patient disease, treatment, and response characteristics were collected. Progression-free survival (PFS) and OS were estimated using the Kaplan–Meier method. Variables reaching significance (p < 0.05) in univariable analysis (UVA) of survival (OS) were included in multivariable analysis (MVA) (Cox).

Results:

Overall, 376 patients with a median follow-up of 16.8 (range: 2.2–218.3) months were included. Median age was 67 (range: 28–91) years, 76% were male, 63% had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0–1, and 41% had BM. All patients received first-line PBC. Patients with BM had inferior median PFS (4.9 months (95% CI 3.6–6.2) versus 6.5 months (95% CI 5.4–7.6), p = 0.03) and median OS (8.8 months (95% CI 7.8–9.7) versus 10.8 months (95% CI 9.1–12.5), p = 0.002). In UVA, ECOG PS 2–3 (p < 0.001), presence of BM (p = 0.002), and WBC count ⩾ 11,000 cells/mm³ (p = 0.001) were associated with inferior survival. Prior cystectomy (p < 0.001) and lack of progression (stable disease, partial or complete response) on treatment was associated with improved OS (p < 0.001). These variables maintained significance in MVA.

Conclusion:

In this retrospective study, mUC patients with BM had worse OS suggesting that BM may be an independent negative prognostic factor and including BM as a stratification factor in future mUC clinical trial designs may be warranted. A greater focus must be placed on novel therapeutic strategies to better manage BM to reduce both morbidity and mortality.