Proposal for new response evaluation criteria following IRE for PHC
| Complete response (CR) | Partial response (PR) | Stable disease (SD) | Progressive disease (PD) | |
| Major criteria One sufficient for PD | ||||
| Tumour size* Longest diameter on axial or coronal plane of the solid enhancing part of the tumour | No residual solid enhancing tumour | Decrease >30% | Decrease ≤30% or increase ≤20% | Increase >20% |
| Metastases New onset, pathology-proven lymph node metastases; cytology-proven ascites (peritonitis carcinomatosa); distant non-nodal metastases | No | No | No | Yes |
| Minor criteria ≥2 needed for PD in absence of major criteria | ||||
| New-onset vessel narrowing* >50% diameter reduction of portal vein, hepatic artery or other major vessels in absence of thrombosis | No | Yes | ||
| New-onset biliary obstruction* Other cause than biliary stent clogging or migration | No | Yes | ||
| New lymph nodes* >15 mm short axis diameter in transversal plane | No | Yes | ||
| New-onset ascites* Cytology negative (otherwise PD); exudate; serum ascites albumin gradient <1.1; CA 19-9 (ascites)>74 U/mL | No | Yes | ||
|
CA 19-9 (plasma) increase >100% (and >74 U/mL)† Without signs for pancreatitis or biliary obstruction | No | Yes | ||
Criteria will be compared with RECIST 1.1 as prognosticators for overall survival for validation. Follow-up CT scans are performed at 6 weeks post-IRE and 6, 12 and 24 months post-IRE.
*All criteria are compared with the first follow-up scan 6 weeks post-IRE.
†Compared with pretreatment value. CA 19-9 rise only significant if latest value is at least 2× the upper limit of normal (2×37 U/mL).
CA 19-9, carbohydrate antigen 19-9; IRE, irreversible electroporation; PHC, perihilar cholangiocarcinoma; RECIST 1.1, Response Evaluation Criteria in Solid Tumours 1.1.