Screening for occult cancer in idiopathic venous thromboembolism — Systemic review and meta-analysis

Background Idiopathic venous thromboembolism (VTE) may be associated with an occult malignancy. Early detection of cancer might be translated to a better prognosis for these patients. However, the efficacy of extensive screening for cancer in patients with idiopathic VTE is controversial. Materials and methods Systemic review and meta-analysis of all available prospective trials comparing extensive to limited screening for occult malignancies in patients with idiopathic VTE. Primary outcome: all-cause mortality. Secondary outcomes: cancer related mortality, early cancer diagnosis, cancer diagnosis at the end of follow up and cancer diagnosis at an early stage. Risk ratios (RR) with 95% confidence intervals (CIs) were estimated and pooled. Results The study included five trials and 2287 patients. Extensive screening did not affect all-cause mortality at the end of follow up [RR 0.86 (95% CI 0.58–1.27)] or cancer-related mortality [RR 0.93 (95% CI 0.54–1.58)]. Yet, it yielded more diagnoses of cancer [RR 2.17 (95% CI 1.42–3.32)]. Rates of cancer diagnosis at an early stage did not differ statistically between the two groups [RR 1.49 (95% CI 0.86–2.56)]. However, analysis of the randomized controlled trials alone showed a tendency towards early stage cancer at diagnosis in extensive screening group in, with results almost statistically significant [RR 2.14 (95% CI 0.98–4.67), p = 0.06]. Conclusions Extensive screening for malignancy after idiopathic VTE does not affect mortality rates. Yet, it yields more cancer diagnoses shortly after the VTE event. Further research is needed to determine whether extensive screening might be proper for specific high risk populations.