Cancer patients are at an increased risk to develop venous thromboembolism (VTE), and VTE may appear before the cancer has become symptomatic. A prognostic score that identifies the risk of patients with VTE to develop cancer has been previously validated internally. Luis Jara-Palomares, M.D., Ph.D. presented the results of the external validation of this prognostic score using the RIETE database in a subsequent cohort of patients.
- The score contains 7 easily available variables (5 clinical, 2 biological) that identify patients at increased risk for occult cancer.
- Less than one third of these patients were considered to be at high risk, and the proportion of patients with cancer in this subgroup was higher than in the low risk subgroup.
These findings, obtained from a large sample of consecutive patients with VTE, externally validated the recently reported score.
The benefits of a diagnostic workup for occult cancer in patients with VTE are controversial. Current guidelines suggest that patients with unprovoked VTE should undergo a limited cancer screen including thorough medical history and physical examination, basic laboratory investigations, and chest x-ray. Clinicians should also ensure that patients are up-to-date regarding age and gender specific cancer screening (colon, breast, cervix, and prostate).
Using the RIETE registry database, a prognostic model to identify patients with VTE who were at increased risk for cancer was built. The researchers dichotomized patient scores into low (≤2 points) or high risk for cancer (≥3 points). However, the resulting score had not been previously externally validated.
From 2014 to 2016, 11,695 VTE patients were recruited. At 12 months, there were 2,580 eligible patients. Of these, 93 (3.6%; 95%CI: 2.9 to 4.4%) were diagnosed with occult cancer. Mean age was 64.7 ± 17.6 years, and 51% were female. The most frequent sites were: colorectal (16.5%), lung (14.6%), and hematologic (14.6%). Among 1,849 patients scoring ≤2 points, 46 (2.5%) had occult cancer. Among 731 patients scoring ≥3 points, 47 (6.4%) had cancer (hazard ratio 2.7; 95% CI 1.8-4.1). C-statistic was 0.65 (95% CI 0.59-0.71).
At 24 months, 103 of 628 eligible patients (16.4%; 95%CI: 13.6 to 19.5%) were diagnosed with occult cancer. Among 429 patients scoring ≤2 points, 53 (12.4%) had occult cancer. Among 199 scoring ≥3 points, 50 (25.1%) had cancer (hazard ratio 2.3; 95% CI 1.5-3.7; p< 0.01). C-statistic was 0.63 (95% CI 0.57-0.69).
This study was successful in externally validating the prognostic model for occult cancer in patients with VTE at 12 and 24 months.