The Safety and Suitability of DNA Sequencing of Tissue Biopsies Performed on Patients Referred to a Phase I Unit

Background: Early-phase clinical trials offer a unique opportunity for patients with cancer. These trials often mandate biopsies to collect tumor tissue for research purposes, requiring patients to undergo invasive procedures. Some trials mandate molecular prescreening, but the success of these analyses relies on the quality and quantity of the tested materials. Additionally, bioptic procedures may result in complications. Methods: We retrospectively examined the records of patients referred to the Early Drug Development (EDD) Unit of the European Institute of Oncology who underwent biopsies for research purposes between January 2014 and December 2022. Our objective was to assess the safety of biopsy procedures and adequacy of the samples for NGS testing. Results: In total, 355 out of 731 patients (48.6%) underwent protocol-mandated biopsies. The most frequent sites of biopsy were the liver, lymph nodes, skin, and breast. Histological diagnosis was achieved in 349 (98%) patients, and NGS testing was successfully conducted in 111/127 (88.4%) cases. Of the 16 unsuccessful NGS attempts, 9 were performed on liver tissue. Unsuccessful NGS testing was attributed to poor sample quality and/or quantity, and the success rate varied significantly based on the specific tests attempted. Complications occurred in a small proportion of patients (4.8%), and none were serious. Conclusions: The non-negligible failure rate of NGS testing highlights the crucial need for implementing specific guidelines and Standard Operating Procedures for samples intended for NGS. With the use of a risk-based biopsy framework to guide clinical decisions, procedure-related complications may be minimized.