Blood Sample Collection in Randomized Controlled Trials for Biomarker Discovery and Validation: Experience of the PREOPANC-2 Trial

Background: This study aimed to investigate the feasibility and yield of blood sample collection in an investigator-initiated nationwide randomized controlled trial (RCT).

Methods: In the PREOPANC-2 trial, 375 patients with (borderline) resectable pancreatic cancer were randomly assigned to two neoadjuvant regiments in 19 centers in the Netherlands (2018-2021). Blood sample collection was scheduled at seven time points before, during, and after treatment. The primary outcome was the proportion of successfully collected blood samples at each scheduled time point.

Results: Of the 375 randomized patients, 12 were excluded from blood sample collection before any treatment. From the remaining 363 patients, 1513 (87 %) of 1748 blood samples were collected, processed, mailed, and centrally stored. The blood samples were collected before treatment from 347 (96 %) of the 363 patients, after the first neoadjuvant cycle from 322 (94 %) of 343 patients, after neoadjuvant treatment (i.e., before surgery) from 260 (83 %) of 313 patients, and after surgery from 210 (77 %) of 271 patients. During the follow-up visits, blood samples were collected from 147 (82 %) of 179 patients 12 months after randomization and from 83 (77 %) of 108 patients after 24 months. A total of 220 samples (13 %) were missing. The most common causes for missing blood samples were scheduling oversights, unsuccessful blood draw attempts, and mailing failures (151 times, 69 %). Blood sample collection was canceled 69 times (31 %) due to COVID-19.

Conclusion: Blood sample collection in the PREOPANC-2 trial had a yield of 96 % before treatment and an overall yield of 87 %. Collection of blood samples for biomarker studies is feasible in a nationwide RCT.