Abstract
I have read the article published by Mutlu et al with a great interest. 1 They examined the mean platelet volume (MPV) values in patients with cancer those developed thrombosis. They have shown that MPV values at the time of thrombosis development were significantly low as compared to those at the time of cancer diagnosis. Platelet count values were also low but no significant association existed. They speculated that platelet volume and count have ignorable effect on thrombosis development in patients with cancer. This is an interesting study. On the other hand, we want to mention minor criticism about this study from methodological aspect.
First, in methods section biochemical analysis part is not clear and they did not mention the tube that the blood sample was collected for whole blood count. This is very important. Platelets exhibit a time-dependent swelling when blood samples are anticoagulated with EDTA, while this swelling does not occur in the presence of citrate. 2 With impedance counting, the MPV increases over time as platelets swell in EDTA, with increase of 7.9% within 30 minutes having been reported and an overall increase of 13.4% over 24 hours, although the majority of this increase occurs within the first 6 hours. 3 The recommended optimal measuring time of MPV is 120 minutes after venipuncture. 4 For reliable MPV measurement, the potential influence of anticoagulant on the MPV must be carefully controlled, either using an alternative anticoagulant (such as citrate) or standardizing the time delay between sampling and analysis (less than 2 hours). This situation is not clear in the study.
Second, there are significant associations of MPV with type 2 diabetes mellitus, prediabetes, smoking, hypertension, hypercholesterolemia, obesity, coronary heart disease, metabolic syndrome, statin and some antihypertensive use, and atrial fibrillation. 5 They did not mention about these factors in patients and control participants in the manuscript. The factors must also have been adjusted in 2 groups. The lower MPV values in patients with cancer with thrombosis may be due to this factor.
Third, they compared the platelet indices between patients with cancer and patients with cancer those who developed thrombosis. They did not compare these groups with control participants. We know that platelet size was elevated in neoplastic disorders particularly in gastric cancer. 6 We can assume that MPV might increase in patients with cancer regardless of thrombosis development. As a result, platelet activation in case of thrombus development in patients with cancer can be negligible.