Symptoms Adversely Impact Survival Among Patients With Cancer and Unsuspected Pulmonary Embolism

Abstract

TO THE EDITOR: In their retrospective cohort study, den Exter et al found no significant differences in recurrent pulmonary emboli (PE), bleeding, or death when comparing patients with cancer who had incidental PE identified on routine staging computed tomography scans and patients with cancer who were diagnosed with PE on the basis of the presence of symptoms. The authors are the first, to our knowledge, to use as a comparator symptomatic patients with dedicated scans demonstrating PE to assess the clinical significance of incidental PE. However, we previously demonstrated that 75% of patients with incidental PE, which we referred to as unsuspected PE (UPE), were actually symptomatic. Variability in the treating oncologists’ index of suspicion for PE may significantly influence whether patients with cancer are referred for radiologic studies to rule out PE, even in the presence of symptoms. Thus, patients who were included in the incidental PE group in the study by den Exter et al may have, at a different institution or with a different physician, been referred for a dedicated study to rule out PE. In a follow-up study that included 70 patients with UPE and 137 ageand stage-matched patients with similar cancers but without PE, we found that UPE adversely affected survival. Notably, patients with symptomatic UPE had significantly shorter survival than patients with asymptomatic clots (unpublished analysis, Fig 1). In fact, respiratory symptoms and fatigue have been independently associated with shorter survival in patients with cancer. Symptoms should thus be considered a critical variable in any survival analysis of patients with cancer and suspected or unsuspected PE. As research and treatment recommendations arise from these and related data, we caution against the use of the words incidental and asymptomatic as interchangeable terms. We recommend that symptoms be clearly reported when possible and that the term unsuspected rather than asymptomatic or incidental be used because of the assumptions and potential bias that are associated with the latter terms.