Regrowth of disappearing liver lesions is rare and is not associated with diminished overall survival.

BACKGROUND

Small colorectal liver metastases (CRLMs) commonly disappear following neoadjuvant chemotherapy. Some authors have suggested upfront surgery, fiducial placement or blind resection of these Disappearing Liver Lesions (DLLs). This retrospective review defines the natural history, recurrence patterns, and survival of patients with DLLs.

METHODS

Patients who underwent liver directed surgery for small CRLMs (≤3 cm) were identified from a prospectively collected database. DLLs were defined as tumors not seen on pre-operative MRI or intra-operative ultrasound following neoadjuvant chemotherapy. Statistical analysis was conducted using Python 3.11(Python software foundation, 2023).

RESULTS

The study included 72 patients with a median follow-up of 55 months. Overall survival was 73 months, and disease recurrence occurred in 46 patients (64%). After neoadjuvant chemotherapy, 29 patients (40%) had at least one DLL. Among patients with DLLs, distant hepatic or systemic recurrence occurred in 21 (72%). However, regrowth of DLL occurred in only 3 patients (10%). Two of these were treated with median survival of 97 months and the third had synchronous extrahepatic disease that precluded additional surgery.

DISCUSSION: DLLs are common, but only rarely regrow (10%). Pre-emptive treatment or fiducial placement for small CRLMs is likely unnecessary and may lead to overtreatment.