High thromboembolic event rate in patients with locally advanced oesophageal cancer during neoadjuvant therapy. An exploratory analysis of the prospective, randomised intergroup phase III trial SAKK 75/08.

Background: High rates of venous thromboembolic events (VTEs), mainly in advanced disease, are reported for patients with cancer of the upper gastrointestinal tract (stomach, pancreas) and for treatment with cisplatin.

Methods: Exploratory analysis of VTEs reported as adverse events and serious adverse events in a prospective, randomised, multicentre, multimodal phase III trial according to VTEs reported as adverse events and severe adverse events. Patients with resectable oesophageal cancer (T2N1-3, T3-4aNx) were randomized to 2 cycles of chemotherapy with docetaxel 75 mg/m, cisplatin 75 mg/m followed by chemo-radiotherapy (CRT) and subsequent surgery (control arm) or the same treatment with addition of cetuximab (investigational arm).

Results: VTEs occurred in 26 of 300 patients included in the trial, resulting in an incidence rate (IR) of 8.7% [95% CI 5.7-12.4%]. A total of 29 VTEs were reported:13 (45%) VTEs were grade 2, 13 (45%) grade 3 and three (10%) fatal grade 5 events. 72% (21/29) of all VTEs occurred preoperatively (IR 6.7%): 14% (4/29) during chemotherapy and 59% (17/29) during CRT. In multivariable logistic regression only adenocarcinoma (IR 11.1%, 21/189 patients) compared to squamous cell cancer (IR 4.5%, 5/111 patients) was significantly associated with VTE-risk during treatment, OR 2.9 [95%CI 1.0-8.4], p = 0.046. Baseline Khorana risk score was 0 in 73% (19/26), 1-2 in 23% (6/26) and 3 in only 4% (1/26) of patients with VTEs.

Conclusion: A high incidence of VTEs during preoperative therapy of resectable oesophageal cancer is observed in this analysis, especially in patients with adenocarcinoma. The role of prophylactic anticoagulation during neoadjuvant therapy in resectable esophageal cancer should be further evaluated in prospective clinical trials. According to our data, which are in line with other analysis of VTE-risk in patients with oesophageal cancer patients treated with neoadjuvant cisplatin-based chemotherapy and CRT, prophylactic anticoagluation could be considered balanced against individual bleeding risks, especially in patients with adenocarcinoma. In addition to the established risk factors, oesophageal adenocarcinoma treated with neoadjuvant cisplatin-based therapy may be regarded as a high-risk situation for VTEs.

Trial Registration: Registered at clinicaltrials.gov, NCT01107639, on 21 April 2010.