Effect of testing for cancer on cancer- and venous thromboembolism (VTE)-related mortality and morbidity in people with unprovoked VTE

BACKGROUND

Venous thromboembolism (VTE) is a collective term for two conditions: deep vein thrombosis (DVT) and pulmonary embolism (PE). A proportion of people with VTE have no underlying or immediately predisposing risk factors and the VTE is referred to as unprovoked. Unprovoked VTE can often be the first clinical manifestation of an underlying malignancy. This has raised the question of whether people with an unprovoked VTE should be investigated for an underlying cancer. Treatment for VTE is different in cancer and non-cancer patients and a correct diagnosis would ensure that people received the optimal treatment for VTE to prevent recurrence and further morbidity. Furthermore, an appropriate cancer diagnosis at an earlier, potentially curative stage could avoid the risk of cancer progression and thus lead to improvements in cancer-related mortality and morbidity. This is an update of a review first published in 2015.

OBJECTIVES

To determine whether testing for undiagnosed cancer in people with a first episode of unprovoked VTE (DVT of the lower limb or PE) is effective in reducing cancer and VTE-related mortality and morbidity and to determine which tests for cancer are best at identifying treatable cancers early.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (16 February 2017). In addition, the CIS searched the Cochrane Register of Studies CENTRAL (2017, Issue 1). We searched trials registries (February 2017) and checked the reference lists of relevant articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials in which people with an unprovoked VTE were allocated to receive specific tests for cancer or clinically indicated tests only were eligible for inclusion in this review. Primary outcomes included all-cause mortality, cancer-related mortality and VTE-related mortality.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed quality and extracted data. We resolved any disagreements by discussion.

MAIN RESULTS

Four studies with 1644 participants met the inclusion criteria (two studies in the original review and two in this update). Two studies assessed the effect of extensive tests versus tests at the physician's discretion) while the other two studies assessed the effect of standard testing plus positron emission tomography (PET)/computed tomography (CT) scanning versus standard testing alone. For extensive tests versus tests at the physician's discretion, the quality of the evidence was low due to risk of bias (early termination of the studies). When comparing standard testing plus PET/CT scanning versus standard testing alone, the quality of evidence was moderate due to a risk of detection bias. The quality of the evidence was downgraded further when detection bias was present in one study with a low number of events.When comparing extensive tests versus tests at the physician's discretion, pooled analysis on two studies showed that testing for cancer was consistent with either a benefit or no benefit on cancer-related mortality (odds ratio (OR) 0.49, 95% confidence interval (CI) 0.15 to 1.67; 396 participants; 2 studies; P = 0.26; low quality evidence). One study (201 participants) showed that, overall, malignancies were less advanced in extensively tested participants than in participants in the control group. In total, 9/13 participants diagnosed with cancer in the extensively tested group had a T1 or T2 stage malignancy compared to 2/10 participants diagnosed with cancer in the control group (OR 5.00, 95% CI 1.05 to 23.76; P = 0.04; low quality evidence). There was no clear difference in detection of advanced stages between extensive tests versus tests at the physician's discretion: one participant in the extensively tested group had stage T3 compared with four participants in the control group (OR 0.25, 95% CI 0.03 to 2.28; P = 0.22; low quality evidence). In addition, extensively tested participants were diagnosed earlier than control group (mean: 1 month with extensive tests versus 11.6 months with tests at physician's discretion to cancer diagnosis from the time of diagnosis of VTE). Extensive testing did not increase the frequency of an underlying cancer diagnosis (OR 1.32, 95% CI 0.59 to 2.93; 396 participants; 2 studies; P = 0.50; low quality evidence). Neither study measured all-cause mortality, VTE-related morbidity and mortality, complications of anticoagulation, adverse effects of cancer tests, participant satisfaction or quality of life.When comparing standard testing plus PET/CT screening versus standard testing alone, standard testing plus PET/CT screening was consistent with either a benefit or no benefit on all-cause mortality (OR 1.22, 95% CI 0.49 to 3.04; 1248 participants; 2 studies; P = 0.66; moderate quality evidence), cancer-related mortality (OR 0.55, 95% CI 0.20 to 1.52; 1248 participants; 2 studies; P = 0.25; moderate quality evidence) or VTE-related morbidity (OR 1.02, 95% CI 0.48 to 2.17; 854 participants; 1 study; P = 0.96; moderate quality evidence). With regards to stage of cancer, there was no clear difference for detection of early (OR 1.78, 95% 0.51 to 6.17; 394 participants; 1 study; P = 0.37; low quality evidence) or advanced (OR 1.00, 95% CI 0.14 to 7.17; 394 participants; 1 study; P = 1.00; low quality evidence) stages of cancer. There was also no clear difference in the frequency of an underlying cancer diagnosis (OR 1.71, 95% CI 0.91 to 3.20; 1248 participants; 2 studies; P = 0.09; moderate quality evidence). Time to cancer diagnosis was 4.2 months in the standard testing group and 4.0 months in the standard testing plus PET/CT group (P = 0.88). Neither study measured VTE-related mortality, complications of anticoagulation, adverse effects of cancer tests, participant satisfaction or quality of life.

AUTHORS' CONCLUSIONS

Testing for cancer in people with unprovoked VTE may lead to earlier diagnosis of cancer at an earlier stage of the disease. However, there is currently insufficient evidence to draw definitive conclusions concerning the effectiveness of testing for undiagnosed cancer in people with a first episode of unprovoked VTE (DVT or PE) in reducing cancer and VTE-related morbidity and mortality. The results could be consistent with either benefit or no benefit. Further good-quality large-scale randomised controlled trials are required before firm conclusions can be made.

Pulmonary Embolism during Stuporous Episodes of Catatonia Was Found to Be the Most Frequent Cause of Preventable Death According to a State Mortality Review: 6 Deaths in 15 Years

Case reports have indicated that pulmonary embolism (PE) can be associated with deaths during episodes of catatonia. A 15-year death registry in Kentucky state psychiatric hospitals was reviewed for deaths during episodes of catatonia. From 2002 to May of 2016, reports of 96 deaths at these state psychiatric hospitals were found and reviewed by the state mortality committee. The charts of the identified catatonic patients were thoroughly reviewed. All 6 deaths occurred during episodes of what Fink and Taylor would call retarded catatonia and Ungvari would call acute stuporous catatonia. The deaths were sudden and appeared to be explained by PE. They accounted for 6% (6/96) of the state hospital deaths. Moreover, they explained 32% (6/19) of the deaths that the committee considered preventable at some level, making pulmonary embolism by far the most important cause of preventable deaths. Catatonia diagnosis and treatment were far from optimal. The stupor in these 6 patients lasted many weeks with a median duration of catatonic symptoms while hospitalized of 45 days in the total sample and 75 days in four patients who died suddenly. If replicated in other mortality databases from other states or countries, two lessons in prevention of these PE deaths in catatonia would be the urgent needs to: 1) improve the skills of clinicians (psychiatrists and internists) for diagnosing and treating stuporous episodes of catatonia and 2) quickly and aggressively treat stuporous episodes of catatonia.

Does the clot burden as assessed by the Mean Bilateral Proximal Extension of the Clot score reflect mortality and adverse outcome after pulmonary embolism?

Background

Rapid diagnosis and risk stratification are important to reduce the risk of adverse clinical events and mortality in acute pulmonary embolism (PE). Although clot burden has not been consistently shown to correlate with disease outcomes, proximally located PE is generally perceived as more severe.

Purpose

To explore the ability of the Mean Bilateral Proximal Extension of the Clot (MBPEC) score to predict mortality and adverse outcome.

Methods

This was a single center retrospective cohort study. 1743 patients with computed tomography pulmonary arteriography (CTPA) verified PE diagnosed between 2005 and 2020 were included. Patients with active malignancy were excluded. The PE clot burden was assessed with MBPEC score: The most proximal extension of PE was scored in each lung from 1 = sub-segmental to 4 = central. The MBPEC score is the score from each lung divided by two and rounded up to nearest integer.

Results

We found inconsistent associations between higher and lower MBPEC scores versus mortality. The all-cause 30-day mortality of 3.9% (95% CI: 3.0-4.9). The PE-related mortality was 2.4% (95% CI: 1.7-3.3). Patients with MBPEC score 1 had higher all-cause mortality compared to patients with MBPEC score 4: Crude Hazard Ratio (cHR) was 2.02 (95% CI: 1.09-3.72). PE-related mortality was lower in patients with MBPEC score 3 compared to score 4: cHR 0.22 (95% CI: 0.05-0.93). Patients with MBPEC score 4 did more often receive systemic thrombolysis compared to patients with MBPEC score 1-3: 3.2% vs. 0.6% (p < .001). Patients with MBPEC score 4 where more often admitted to the intensive care unit: 13% vs. 4.7% (p < .001).

Conclusion

We found no consistent association between the MBPEC score and mortality. Our results therefore indicate that peripheral PE does not necessarily entail a lower morality risk than proximal PE.

Sex as a prognostic factor for mortality in adults with acute symptomatic pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is relatively common worldwide. It is a serious condition that can be life-threatening. Studies on the relationship between adverse outcomes of this condition and whether a patient is male or female have yielded inconsistent results. Determining whether there is an association between sex and short-term mortality in patients with acute PE is important as this information may help guide different approaches to PE monitoring and treatment.

OBJECTIVES

To determine whether sex (i.e. being a male or a female patient) is an independent prognostic factor for predicting mortality in adults with acute symptomatic pulmonary embolism.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases, and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials register up to 17 February 2023. We scanned conference abstracts and reference lists of included studies and systematic reviews. We also contacted experts to identify additional studies. There were no restrictions with respect to language or date of publication.

SELECTION CRITERIA

We included phase 2-confirmatory prognostic studies, that is, any longitudinal study (prospective or retrospective) evaluating the independent association between sex (male or female) and mortality in adults with acute PE.

DATA COLLECTION AND ANALYSIS

We followed the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of prognostic factor studies (CHARMS-PF) and the Cochrane Prognosis Methods Group template for prognosis reviews. Two review authors independently screened the studies, extracted data, assessed the risk of bias according to the Quality in Prognosis Studies (QUIPS) tool, and assessed the certainty of the evidence (GRADE). Meta-analyses were performed by pooling adjusted estimates. When meta-analysis was not possible, we reported the main results narratively.

MAIN RESULTS

We included seven studies (726,293 participants), all of which were retrospective cohort studies with participants recruited and managed in hospitals between 2000 and 2018. Studies took place in the USA, Spain, and Japan. Most studies were multicentre. None were conducted in low- or middle-income countries. The participants' mean age ranged from 62 to 69 years, and the proportion of females was higher in six of the seven studies, ranging from 46% to 60%. Sex and gender terms were used inconsistently. Participants received different PE treatments: reperfusion, inferior vena cava filter, anticoagulation, and haemodynamic/respiratory support. The prognostication time (the point from which the outcome was predicted) was frequently omitted. The included studies provided data for three of our outcomes of interest. We did not consider any of the studies to be at an overall low risk of bias for any of the outcomes analysed. We judged the certainty of the evidence as moderate to low due to imprecision and risk of bias. We found moderate-certainty evidence (due to imprecision) that for female patients there is likely a small but clinically important reduction in all-cause mortality at 30 days (odds ratio (OR) 0.81, 95% confidence interval (CI) 0.72 to 0.92; I2 = 0%; absolute risk difference (ARD) 24 fewer deaths in women per 1000 participants, 95% CI 35 to 10 fewer; 2 studies, 17,627 participants). However, the remaining review outcomes do not indicate lower mortality in female patients. There is low-certainty evidence (due to serious risk of bias and imprecision) indicating that for females with PE, there may be a small but clinically important increase in all-cause hospital mortality (OR 1.11, 95% CI 1.00 to 1.22; I2 = 21.7%; 95% prediction interval (PI) 0.76 to 1.61; ARD 13 more deaths in women per 1000 participants, 95% CI 0 to 26 more; 3 studies, 611,210 participants). There is also low-certainty evidence (due to very serious imprecision) indicating that there may be little to no difference between males and females in PE-related mortality at 30 days (OR 1.08, 95% CI 0.55 to 2.12; I2 = 0%; ARD 4 more deaths in women per 1000 participants, 95% CI 22 fewer to 50 more; 2 studies, 3524 participants). No study data was found for the other outcomes, including sex-specific mortality data at one year. Moreover, due to insufficient studies, many of our planned methods were not implemented. In particular, we were unable to conduct assessments of heterogeneity or publication bias or subgroup and sensitivity analyses.

AUTHORS' CONCLUSIONS

The evidence is uncertain about sex (being male or female) as an independent prognostic factor for predicting mortality in adults with PE. We found that, for female patients with PE, there is likely a small but clinically important reduction in all-cause mortality at 30 days relative to male patients. However, this result should be interpreted cautiously, as the remaining review outcomes do not point to an association between being female and having a lower risk of death. In fact, the evidence in the review also suggested that, in female patients, there may be a small but clinically important increase in all-cause hospital mortality. It also showed that there may be little to no difference in PE-related mortality at 30 days between male and female patients. There is currently no study evidence from longitudinal studies for our other review outcomes. Although the available evidence is conflicting and therefore cannot support a recommendation for or against routinely considering sex to quantify prognosis or to guide personalised therapeutic approaches for patients with PE, this Cochrane review offers information to guide future primary research and systematic reviews.