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

abstract - EvidenceUpdates: Cochrane Review: Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy (including professional commentaries)

Abstract

BACKGROUND:  Venous thromboembolism (VTE) often complicates the clinical course of cancer disease. The risk is further increased by chemotherapy but the safety and efficacy of primary thromboprophylaxis in cancer patients treated with chemotherapy is uncertain. OBJECTIVES:  To assess the efficacy and safety of primary thromboprophylaxis in ambulatory cancer patients receiving chemotherapy.  AUTHORS' CONCLUSIONS:   Primary thromboprophylaxis with LMWH significantly reduced the incidence of symptomatic VTE in ambulatory cancer patients treated with chemotherapy. However, the lack of power hampers definite conclusions on the effects on major safety outcomes, which mandates additional studies to determine the risk to benefit ratio of LMWH in this setting.

Comments from Clinical Raters
Oncology - Breast

summary: Risk of Venous and Arterial Thromboembolic Events Associated With Anti-EGFR Agents: A Meta-Analysis of Randomized Clinical Trials - OncologySTAT

 

SUMMARY

OncologySTAT Editorial Team

"Venous and arterial thromboembolism events (VTEs and ATEs) are common in patients with cancer and are a frequent cause of mortality in these patients. Antiangiogenic agents that target vascular endothelial growth factor receptor (VEGFR), such as sunitinib, sorafenib, and bevacizumab, are associated with increased risk of VTEs and ATEs. Other drugs target the epidermal growth factor receptor (EGFR), such as the monoclonal antibodies cetuximab and panitumumab, and the oral tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib. This meta-analysis evaluated the risk of VTEs and ATEs associated with the anti-EGFR agents cetuximab, panitumumab, erlotinib, and gefitinib.
Medline and EMBASE were searched for randomized controlled phase II or III trials in which cetuximab, panitumumab, erlotinib, or gefitinib was used as treatment for patients with cancer....."

abstract: Prevention and treatment of venous thromboembolism (blood clots) in patients with cancer

abstract: Cochrane Review - Anticoagulation for the initial treatment of venous thromboembolism in patients with cancer.

BACKGROUND:

Compared to patients without cancer, patients with cancer who receive anticoagulant treatment for venous thromboembolism are more likely to develop recurrent venous thromboembolism (VTE).

AUTHORS' CONCLUSIONS:

LMWH (low molecular weight heparin)  is possibly superior to UFH (unfractionated heparin) in the initial treatment of VTE in patients with cancer. Additional trials focusing on patient important outcomes will further inform the questions addressed in this review.

abstract: Oral Contraceptives and the Risk of Venous Thromboembolism: An Update

Access : Hospitalisation for venous thromboembolism in cancer patients and the general population: a population-based cohort study (abstract)

Conclusions:

Risk of VTE is higher among cancer patients than in the general population. Predictors of VTE include recency of cancer diagnosis, cancer site, stage and the type of cancer-directed treatment.

Summary- Clinical burden of venous thromboembolism

Conclusions:

Even among high-risk groups it is not possible to identify individuals who will go on to develop VTE, and, therefore, thromboprophylaxis is a recommended component of the management of high-risk patients. Ensuring patients receive safe, effective, easily administered antithrombotic therapy both in hospital and post-discharge, for a sufficient length of time, should be central to any strategy to reduce incident or recurrent VTE and minimise the risk of long-term complications.