Artikel
Intraoperative frozen section fails to improve diagnostic accuracy in stereotactic biopsies but doubles procedure length – results of a prospective randomized study
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Veröffentlicht: | 13. Mai 2014 |
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Objective: Frame-based stereotactic biopsy has high technical standards, high diagnostic accuracy and a very precise target point definition due to multimodal image integration. However, intraoperative frozen section is considered the “gold standard” in this procedure. Omitting frozen section may result in a reduced procedure length and in structural improvement of operation schedules. Therefore, we prospectively investigated “intraoperative frozen section” vs. “no frozen section” in regard to diagnostic accuracy, procedure time, morbidity and mortality.
Method: Inclusion criteria were 18 years of age, indication for histological sampling using stereotactic biopsy and preoperative imaging. 2 University hospitals randomized patients to arm A (intraoperative frozen section) or arm B (no frozen section). After preoperative informed consent, acquisition of intraoperative imaging patients were randomized to arm A or B. Patients were stratified to “contrast-CT-positive”, “contrast-CT-positive plus MR-fusion”, “contrast-CT-negative plus MR-fusion” or “only MR”. Histology was considered “negative”, if results were non-conclusive or clinical course suggested a different histology.
Results: 150 patients were prospectively and consecutively included. 73 patients were randomized to arm A and 77 to arm B. Both arms did not differ in regard to lesion location, group stratification, number of samples or perioperative complication (p>0.05). 24/73 patients (33%) in arm A received additional trajectories after frozen section. Procedure time was 67.9 ± 2.5 (arm A) vs. 35.7 ± 2.1 minutes in arm B (p<0.0001). Conclusive histology did not differ in its diversity (p=0.63). Histology was inconclusive in 8.2% in arm A and in 5.2% in arm B providing diagnostic accuracy in 91.8% and 94.8%. Omitting the frozen section proved to be non-inferior in regard to histological accuracy (p<0.0001; non-inferiority test). Non-conclusive histology was seen more frequently in CT-negative lesions (Fisher exact test p=0.026) and if histological samples appeared macroscopically not or only slightly changed (Fisher exact test p=0.0018).
Conclusions: Intraoperative frozen section may be omitted without losing diagnostic accuracy in stereotactic biopsy. Omitting frozen section reduced procedure time by 50%. CT-negative lesions showed non-conclusive histology 5-times more often than did CT-positive lesions. If histological samples appeared macroscopically altered, the positive predictive value for conclusive histology was 95%.