Evaluation of Tissue Adequacy by Computed Tomography-Guided Needle Biopsy for Comprehensive Genomic Profiling Following Chemotherapy

Background Computed tomography-guided needle biopsy (CT-NB) has become increasingly important for comprehensive genomic profiling (CGP). However, factors influencing tissue adequacy for CGP after chemotherapy remain unclear. Purpose This study aimed to evaluate the factors affecting the tissue adequacy of CT-NB specimens for CGP following chemotherapy. Materials and methods We retrospectively reviewed patients who underwent CT-NB for intended CGP after chemotherapy between June 2020 and December 2024. Tissue adequacy was defined as tumor content ≥20% on pathological assessment. Adequacy rates were calculated, and associations with tumor size, number of needle passes, and 18F-fluorodeoxyglucose (FDG) uptake were evaluated. Results This study included 33 patients (median age: 71 years). Biopsy sites were the bone (n=9), liver (n=8), lymph nodes (n=5), and others (n=11). One procedure was technically unsuccessful, and five patients did not proceed to CGP owing to clinical deterioration or other reasons. Among 27 evaluable patients, 17 (63%) provided adequate specimens, whereas 10 (37%) were inadequate owing to insufficient tumor cells. Tissue adequacy was not significantly associated with tumor size or the number of needle passes. Among FDG uptake parameters (n=16), the maximum standard uptake value (SUVmax) showed no significant difference between the adequate and inadequate groups, whereas the mean standard uptake value (SUVmean) demonstrated a statistically significant difference between both groups. Ultimately, the SUVmax/SUVmean ratio showed no significant relationship with tissue adequacy. Conclusion CT-NB can provide tissue for CGP after chemotherapy; however, adequate tissue acquisition remains challenging. In patients with available FDG-PET/CT, a higher SUVmean was associated with tissue adequacy.