Incidence, characteristics, and implications of thrombo-embolic events in patients with urothelial carcinoma of the bladder undergoing neoadjuvant chemotherapy.

393 Background: Neoadjuvant chemotherapy (NAC), in combination with radical cystectomy (RC), is associated with a significant survival advantage for patients with muscle-invasive bladder cancer. Chemotherapy as well as pelvic surgery are significant risk factors for thrombo-embolic events (TEE). The objectives of this study were to investigate the incidence and characteristics of TEE during and after NAC and subsequent RC for urothelial bladder cancer patients. Methods: A retrospective study was carried out on 827 consecutive patients who underwent NAC and cystectomy for urothelial bladder carcinoma from 2002 to 2014 at ten different tertiary centers across North America and Europe. The median time of follow-up from bladder cancer diagnosis was 13 months (range 1-119 months). The incidence (venous, arterial, port-site or deep vein thrombosis, thrombosis, clinical or incidentally detected pulmonary embolism) and timing of TEE (before or after ( < or > 30 days) RC) and Khorana score (based on baseline hemoglobin, platelet and leukocyte counts, BMI and tumor site, which was established for cancer patients treated with chemotherapy) was determined for all patients. Multivariate analysis was performed on 827 patients. Kaplan Meier survival curves and log rank test were used to compare survival between patients who developed TEE and those who did not. Results: The Khorana criteria indicated intermediate TEE risk in most patients. Khorana risk score was 1 or 2 in 88% of patients. Nevertheless, the incidence of TEE in patients undergoing NAC was 15%. 59 TEE were detected pre-operatively (7.1%), 21 early within 30 days of RC (2.5%) and 36 late post-operatively (4.3%). 32% of the TEE events were detected incidentally by imaging, 68% were detected clinically. Median overall survival of patients who developed TEE was 28 months compared to 71 months for those who did not develop TEE (p = 0.012). Conclusions: This multi-centre retrospective study suggests that TEE are very common in bladder cancer patients undergoing NAC followed by RC and is associated with poorer survival. Further investigation with a prospective prevention trial is warranted.