Cambridge kidney One-Stop Mass Investigation Clinic (CkOSMIC): A Nonrandomised Feasibility Study.

Background and objective: Our aim was to evaluate the feasibility and outcomes of a one-stop renal mass biopsy (RMB) clinic at which same-day biopsy results were facilitated by the use of confocal microscopy.

Methods: The Cambridge kidney One-Stop Mass Investigation Clinic (CkOSMIC) was established in January 2024. Patients underwent an ultrasound (US)-guided biopsy, and the sample was assessed via a confocal laser microscopy scan, which provided results within minutes. Traditional histopathology processing was also conducted. A historical cohort of patients who underwent RMB according to the standard pathology pathway was used as the comparator. We assessed the feasibility, safety, and diagnostic accuracy, as well as the acceptability among patients and clinicians.

Key findings and limitations: Overall, CkOSMIC US-guided biopsy was conducted in 50 patients over a period of 12 mo, of whom 48 received a provisional diagnosis immediately. The sensitivity and specificity for identification of malignancy were 94% (29/31; 95% confidence interval [CI] 79-98%) and 100% (17/17; 95% CI 82-100%), respectively. There was complete agreement between confocal and final pathology for 91.7% (n = 44) of the patients, and partial concordance (cancer identified but equivocal histological subtype) for 8.3% (n = 4). Time from first consultation to a treatment decision, and time from biopsy to a treatment decision were significantly shorter in the CkOSMIC pathway (25 d, interquartile range [IQR] 15-42) than in the standard pathway (55 d, IQR 41-77; p < 0.001). Time from biopsy to a treatment decision was also significantly shorter in the CkOSMIC pathway (0 d) than in the standard pathway (24 d, IQR 17-34; p < 0.001). All participants were "satisfied" or "very satisfied" with the pathway.

Conclusions and clinical implications: CkOSMIC was feasible and showed high sensitivity and specificity in diagnosing cancer, while being safe and acceptable. It allows cancer targets to be met, reduces hospital visits and potentially reduces anxiety of delays in forming a treatment plan.