Abstract
OBJECTIVE: To assess the association of venous thromboembolism (VTE) with different chemotherapy regimens in patients with urothelial tract cancer. PATIENTS AND METHODS: We identified patients aged ≥66 years, diagnosed with urothelial tract cancer in the period 1998 to 2011 in the Surveillance, Epidemiology, and End Results (SEER) Medicare-linked database. The chemotherapy regimens analysed were gemcitabine/cisplatin (GC), methotrexate/vinblastine/doxorubicin/cisplatin (MVAC), or gemcitabine/carboplatin (CarboG). Propensity scores for treatment regimen based on comorbidities, tumour characteristics, age, and year of diagnosis were calculated. VTE rates within 120 days of chemotherapy initiation were calculated. VTE risk stratified by chemotherapy regimen was modelled using multivariable logistic regression, adjusting for treatment propensity scores and additional demographic characteristics. Overall survival stratified by VTE and chemotherapy regimen was estimated using Kaplan-Meier methods and the log-rank test. RESULTS: Of 5594 identified patients, a VTE occurred in 13.0%. The VTE rates within 120 days of chemotherapy initiation were 15.3% for GC, 8.7% for MVAC, and 12.0% for CarboG. On multivariable analysis, MVAC (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.39-0.94) and CarboG (OR 0.71, 95% CI: 0.59-0.85) were associated with lower VTE risk compared with GC. VTE was associated with worse overall survival (P < 0.001). CONCLUSIONS: Compared with GC, MVAC and CarboG were associated with a lower rate of VTE. This finding suggests that gemcitabine may add to the increased thrombosis risk from cisplatin. Additionally, patients with a VTE had worse survival outcomes than those without a VTE. Analysis of the risk of blood clots with different chemotherapy regimens in patients with urothelial tract cancer showed that GC was associated with the highest rate. We also found that blood clots were associated with worse patient outcomes.