Table 3.
Effect of CSR-guided re-resections on the final margin status and reduction of secondary surgeries on case level (n = 362)
| Overall cohort | cCR after NACT | Non-cCR after NACT | |
|---|---|---|---|
| Number of cases | 362 (100%) | 167 (100%) | 195 (53.9%) |
| Initial PMR (CSR) | 194 (53.6%) | 82 (49.1%) | 112 (57.4%) |
| True positive | 35 (9.7%) | 10 (6.0%) | 25 (12.8%) |
| False positive | 159 (43.9%) | 72 (43.1%) | 87 (44.6%) |
| true negative | 150 (41.4%) | 75 (44.9%) | 75 (38.5%) |
| False negative | 18 (5.0%) | 10 (6.0%) | 8 (4.1%) |
| Sensitivity | 66.0% | 50.0% | 75.8% |
| Specificity | 48.5% | 51.0% | 46.3% |
| PPV | 18.0% | 12.2% | 22.3% |
| NPV | 89.3% | 88.2% | 90.4% |
| Final PMR (pathologic assessment) | 16 (4.4%) | 6 (3.6%) | 10 (5.1%) |
| Conversion of margin status through CSR | 19 (5.2%) | 5 (3.0%) | 14 (7.2%) |
| NNT for conversion of margin status through CSR | 20 | 34 | 14 |
| secondary surgeries | 37 (10.2%) | 8 (4.8%) | 29 (14.9%) |
|
Number of secondary surgeries avoided through CSR (absolute risk reduction) |
38 (10.5%) | 5(3.0%) | 33 (16.9%) |
| NNT to avoid secondary surgeries through CSR | 10 | 34 | 6 |
Patients with a cCR have a lower prevalence of initially positive resection margins and a higher number needed to treat to avoid secondary surgeries through CSR-guided intraoperative re-excisions
cCR clinical complete response, CSR Conventional Specimen Radiography, NACT neoadjuvant chemotherapy, NNT number needed to treat, PMR positive margin rate in histology