Share on Facebook
Share on Twitter
Share on LinkedIn
Share by Email
Print
Results from the PATHFINDER study suggest that multicancer early detection (MCED) testing is feasible in practice, but more research is needed to assess its clinical utility, according to investigators.
The team found that a majority of positive MCED test results were false positives, and the time to diagnostic resolution was longer in these patients than in patients with a true-positive result. These findings were published in The Lancet.
For this study (ClinicalTrials.gov identifier: NCT04241796), 6621 patients underwent MCED testing. The patients were recruited from oncology and primary care outpatient clinics in the US, were 50 years of age or older, and did not have signs or symptoms of cancer.
Of the 92 patients (1.4%) with a positive MCED test result, 35 (38%) were ultimately diagnosed with cancer, but 57 (62%) had a false-positive test result.
Of the 6529 patients with a negative MCED test result, 6235 (95.5%) had a true-negative result, 86 (1.3%) had a false-negative result, and 208 (3.2%) had unknown cancer status at the end of the study.
Among patients with a true-positive test result, the median time to diagnostic resolution was 79 days. Most of these patients had laboratory testing (79%), imaging (91%), and a procedure of some kind (82%). Three patients had surgery.
Among patients with false positives, the median time to diagnostic resolution was 162 days. Most patients had laboratory testing (88%) and imaging (93%), but few underwent a procedure (30%), and 1 had surgery.
Overall, the rate of true-positive results was 0.5%, and the rate of false positives was 0.9%. The test’s positive predictive value was 38%, the negative predictive value was 98.6%, the specificity was 99.1%, and the cancer yield rate was 0.53%. The number of patients needed to screen to detect 1 cancer was 189.
Most patients with a true-positive result (97%) had a correct first or second prediction for the site of cancer origin. Of the patients with a false positive, 61% had a hematologic site prediction, and 34% of these patients had a hematologic precursor condition.
A refined version of the MCED test was given to 98.7% of the original cohort (n=6578). This version of the test had a specificity of 99.5% and a positive predictive value of 43.1%. False positives for hematologic malignancies decreased from 61% with the original test to 12% with the new version.
“[P]ATHFINDER establishes the feasibility of MCED testing in ambulatory practice,” the investigators wrote. “This experience lays the foundation for larger-scale studies to investigate the safety, utility, and clinical effectiveness of MCED testing as a cancer screening strategy.”
Disclosures: This study was supported by Grail. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Schrag D, Beer TM, McDonnell CH III, et al. Blood-based tests for multicancer early detection (PATHFINDER): A prospective cohort study. Lancet. 2023;402:1251-1260. doi:10.1016/S0140-6736(23)01700-2
This article originally appeared on Cancer Therapy Advisor
