Correspondence/Author's Response: Paraneoplastic Thrombocytosis in Ovarian Cancer — NEJM

Paraneoplastic Thrombocytosis in Ovarian Cancer — NEJM

Correspondence

Paraneoplastic Thrombocytosis in Ovarian Cancer

N Engl J Med 2012; 366:1840 May 10, 2012

To the Editor:

The mean platelet volume (MPV), analogous to the calculation of the mean corpuscular volume, is calculated as the plateletcrit divided by the total number of platelets. Although the MPV is readily available on a routine blood count, many laboratories do not report the MPV to clinicians because of the lack of standardization and the dependency of the results on the age of the sample and the method of measurement. Stone et al. (Feb. 16 issue)1 found that thrombocytosis was associated with shortened survival and advanced disease in patients with ovarian cancer. A recent population-based study has shown the MPV to be a predictor of venous thromboembolism.2 Other studies have shown the MPV to be a predictor of cardiovascular risk, with an elevated MPV associated with increased mortality after acute myocardial infarction and an increased rate of restenosis after coronary angioplasty.3 Similarly, an elevated MPV is associated with a worse outcome for acute ischemic cerebrovascular events, independent of other clinical factors.4 We would like to know whether the investigators obtained data on the MPV in their study cohort, and if so, whether they found any correlation between the MPV and survival, independent of thrombocytosis.

Harris V. Naina, M.D.
Samar Harris, M.D.
UT Southwestern, Dallas, TX
harris.naina@utsouthwestern.edu

No potential conflict of interest relevant to this letter was reported.
4 References

Author/Editor Response

Platelet size, as measured by the MPV and platelet distribution width, correlates with platelet reactivity.1 Retrospective data suggest that the MPV has potential prognostic and diagnostic value in hematologic and cardiovascular disorders.2 However, it is not known whether the MPV is a useful prognostic marker in patients with cancer. Although the focus of our investigation was on the mechanisms and effect of thrombocytosis on clinical outcomes in ovarian cancer, in response to the inquiry from Naina and Harris, we examined the association among the MPV, thrombocytosis, and survival in 150 patients with newly diagnosed advanced epithelial ovarian cancer. In this data set, the median MPV was 8 fl (range, 6 to 11). MPV levels were inversely correlated with platelet count (r=–0.45, P<0.001). Survival rates were not associated with the MPV (where a high MPV was defined as an MPV greater than either the median or the cutoff value used by our institution [>10.4 fl]). The value of alternative cutoff levels for MPV for prognostic evaluation is unknown.

Rebecca L. Stone, M.D.
Vahid Afshar-Kharghan, M.D.
Anil K. Sood, M.D.
University of Texas M.D. Anderson Cancer Center, Houston, TX