Aspirin Use And The Thrombocytic Cancer Patient with Acute Coronary Disease

Abstract & Commentary

By William B. Ershler, MD, Editor,INOVA Fairfax Hospital Cancer Center, Fairfax, VA; Director, Institute for Advanced Studies in Aging, Washington, DC.

Synopsis: Aspirin can be life saving in patients with acute coronary events, but its use in patients with cancer, particularly in those with thrombocytopenia, is often avoided, presumably for fear of hemorrhagic complications. In this retrospective review of 70 patients who sustained an acute coronary event while at MD Anderson Cancer Center, over a one year period, aspirin treatment was associated with significantly better survival and this was true for the subgroup with normal platelet counts and the group with thrombocytopenia. Furthermore, there was no observed hemorrhagic complication in the aspirin treated patients.

Source: Starkiss MG, et al. Impact of aspirin therapy in cancer patients with thrombocytopenia and acute coronary syndromes. Cancer. 2007;109:621-627.

Over the years, the benefit of aspirin and beta blocker therapy in the treatment of Acute Coronary Syndrome (ACS) has been well documented.1 However, the evidence has been drawn on well conducted clinical trials that, for the most part, were devoid of patients with cancer and also those with thrombocytopenia. Thus, in the setting of an acute coronary event in a patient with cancer and thrombocytopenia, it has not been clearly demonstrated that aspirin or other antiplatelet therapy would have the same benefit and be without substantial additional risk. In fact, aspirin therapy has often been withheld in ACS patients who happen to also have cancer with or without thrombocytopenia, presumably for fear of hemorrhagic complications.

The current study, a retrospective analysis of patients with acute coronary syndrome during an inpatient stay at MD Anderson Cancer Center during the year 2001 was designed to evaluate the impact of aspirin therapy on relevant clinical outcomes including overall survival. For the diagnosis of an acute coronary syndrome (ACS), at least two of three criteria had to be documented. These included chest pain, characteristic EKG changes and elevation in cardiac enzymes. Seventy patients during the one-year stay met these criteria.

ACS patients were examined in the context of their platelet count (above or below 100 x106/ul) at the time of coronary event. Once categorized this way (those with normal platelet counts and those with thrombocytopenia), an examination of baseline risk factors for adverse outcomes from coronary disease revealed no significant differences. Of the total 70 ACS patients, 43 had "normal" platelet counts and 27 had thrombocytopenia (mean platelet count for this group was 32 x106/ul). The 7-day survival rate was significantly better for those with normal platelets (77% vs 37%). In both groups, the survival of patients who received aspirin was significantly higher than that in patients who did not receive aspirin. In the thrombocytopenia group, the overall 7-day survival for those who received aspirin was 90% compared with 6% for those who did not receive aspirin. Similarly, in the group with normal platelet counts, the overall survival for those who received aspirin was 88% compared with 45% for those who did not.

Importantly, no significant bleeding was observed in any patient, including those with low platelet counts.

Commentary

Physicians are commonly confronted with difficult decisions for which hard evidence is unavailable. We frequently face this when making treatment decisions for cancer patients who, for any of a number of reasons (eg, functional impairments or co-morbidities) have little in common with the patients entered on the clinical trials that ultimately are used to define treatment standards. The current report is representative. The cardiology literature is rife with data about the life saving effects of aspirin in the acute coronary setting. Yet, these data are derived from trials on which cancer patients and patients with thrombocytopenia have been excluded. Internists, conservative by nature, will often rely on clinical judgment when the intervention is risky and the published guidelines not totally applicable. In this regard, the current report may be of great value. Although the series was small, the therapeutic benefit of aspirin was clearly demonstrated in a consecutive series of cancer patients, with or without thrombocytopenia, who were experiencing an acute coronary event. Furthermore, anticipated hemorrhagic complications were not observed, even in those with thrombocytopenia. Oncologists often find themselves caring for very ill patients and some quite possibly will develop acute coronary events. The take home message from the MD Anderson experience is that cancer patients with acute coronary events have a high rate of fatality that can be reduced in the acute setting by aspirin. Furthermore, when aspirin was used in patients with thrombocytopenia, there was significantly less mortality and, at least in this series, no observed hemorrhagic complications.

Reference

1. Braunwald E, et al. J Am Coll Cardiol. 2002;40:1366-1374.