“If You Prick Us, Do We Not Bleed?” Whom Should We Choose?
Authors: Mairéad G. McNamara, Angela Lamarca, Richard A. Hubner, Juan W. Valle
Journal: Journal of Clinical Oncology (2016)

If You Prick Us, Do We Not Bleed?"Whom Should We Choose?Pelzer et al 1 report on the high efficacy and feasibility of primary pharmacologic prevention of symptomatic venous thromboembolic events in outpatients with advanced pancreatic cancer in the CONKO-004 (Prospective Randomized Trial of Simultaneous Pancreatic Cancer Treatment With Enoxaparin and Chemotherapy) and are to be congratulated for performing this prospective, academically led study in an area where there is a great need for improvement in patient outcomes.However, should all patients within this disease group be treated comparably?The 2014 updated ASCO clinical practice guidelines 2 concluded that routine prophylaxis was not recommended for patients with cancer in the outpatient setting but may be a consideration for selected high-risk patients.It is not clear from the study by Pelzer et al 1 whether there is a higher-risk subpopulation within the advanced pancreatic cancer disease group who may derive more benefit from prophylactic anticoagulation.Neither are we significantly enlightened as to the risk threshold to apply for identification of patients for thromboprophylaxis, with various levels of risk reported as relevant (ie, greater than 10% 3 or 15% to 30%). 4 It is stated that patients were randomly assigned to treatment arms, with patient characteristics being well balanced, but the impact of potentially important characteristics such as performance status, disease extent, lymph node disease location, and the use of red-cell growth factors, platinum-based therapy and central venous catheters cannot be assessed.Specifically, how many patients with poor performance status, previously reported by Khorana et al as a covariable associated with development of venous thromboembolism (VTE), 3 went on to develop such an event?The inclusion criteria for the Riess study, published in 2008 5 , stated that patients with histologically or cytologically confirmed stage IV pancreatic cancer were eligible, but patients with locally advanced disease seem to have been included in the Pelzer et al report. 1 In the study, 26% and 22% of patients with locally advanced disease were enrolled in the enoxaparin and observation arms, respectively.It would be interesting to know if there were differences in occurrences of VTE between those with M0 and M1 disease, as reported by Chew et al. 6 In the enoxaparin and observation arms, 18% and 10% of patients, respectively, had lymph node metastases.What were the radiologic parameters of nodal involvement in this current study? 1 Although accepting the differing sites of primary, large, retroperitoneal lymph node metastases have been associated with VTE in patients with a diagnosis of disseminated germ cell tumors and may relate to venous stasis or reflect greater disease burden, 7 and vascular or lymphatic compression by tumor is an entity commonly reported in patients with advanced pancreatic cancer, acknowledging that it is more likely that the lymph node involvement in patients with pancreatic cancer is local.