How do I assess resectability of colorectal liver metastases, considering Eastern Cooperative Oncology Group (ECOG) performance status, cardiopulmonary reserve, imaging of hepatic lesions, and future liver remnant (FLR) volume?

Assessment of Resectability in Colorectal Liver Metastases

Resectability is determined by the ability to achieve R0 resection (clear margins) while leaving sufficient functioning liver remnant—approximately one-third of standard liver volume or minimum two segments—regardless of number, size, or distribution of metastases. 1

Core Resectability Criteria

The fundamental assessment requires three elements to be satisfied simultaneously:

• Technical feasibility of R0 resection: All macroscopic disease must be removable with negative margins, as determined by the hepatobiliary surgical team in conjunction with an experienced radiologist 1
• Adequate future liver remnant (FLR): Approximately one-third of standard liver volume or equivalent of minimum two liver segments must remain, calculated by CT volumetry 1
• Medical fitness for surgery: The liver surgeon and anesthetist jointly determine cardiopulmonary reserve and overall fitness for major hepatic resection 1

Critical point: Patients with solitary, multiple, and bilobar disease are all candidates for resection if these three criteria are met—the number and location of deposits do not compromise survival as long as all macroscopic disease is resected. 1

Imaging Assessment Protocol

For patients with identified liver metastases:

• CT chest, abdomen, and pelvis should be performed by or using protocols agreed with the liver surgery unit 1
• Liver-specific imaging per local hepatobiliary unit protocol (often MRI) 1
• Do not biopsy hepatic lesions without discussion with the regional hepatobiliary unit 1
• High-risk patients (T4 perforated primary, C2 apical node involvement) require careful preoperative investigations that may include PET and laparoscopy 1

Patient Fitness Evaluation

The operating surgeon and anesthetist are best positioned to assess fitness:

• ASA and POSSUM grades provide objective assessment of perioperative risk 1
• If medically unfit for surgery, patients should be considered for ablative therapy 1
• ECOG performance status should be good, though this is implicit in surgical candidacy evaluation 2

Management of Extrahepatic Disease

Extrahepatic disease is not an absolute contraindication. Consider resection in patients with:

• Resectable/ablatable pulmonary metastases 1, 2
• Resectable isolated extrahepatic sites (spleen, adrenal, or resectable local recurrence) 1, 2
• Local direct extension of liver metastases to diaphragm/adrenal that can be resected 1, 2

Contraindication: Uncontrollable extrahepatic disease remains a contraindication to liver resection 1

Borderline Resectable Disease

For tumors initially deemed borderline or unresectable:

• Refer to regional hepatobiliary unit for discussion regarding conversion chemotherapy 1
• Portal vein embolization can increase hepatic functional reserve 1
• Two-stage hepatectomy may achieve resectability 1, 3
• Combinations of surgery and ablation can address disease when complete resection alone is not feasible 1, 2
• Approximately 13% of initially unresectable patients can be converted to resectable status with modern chemotherapy 2

Important: Surgery should be performed promptly after conversion to avoid chemotherapy-induced hepatotoxicity 2

Common Pitfalls to Avoid

Resectability is frequently underestimated by non-hepatobiliary surgeons and medical oncologists. Studies demonstrate that hepatobiliary surgeons consider disease resectable in 92% of cases versus only 57% by other specialists. 4, 5 This underscores a critical point: early consultation with an experienced hepatobiliary surgeon is essential, as assessment of resectability varied significantly between specialties and hepatobiliary referral was not considered in a substantial proportion of cases erroneously deemed unresectable. 4

Do not use outdated criteria: Historical restrictions based on number of metastases (>3-4), size of lesions, or mandatory 1-cm margins are no longer valid—resectability now centers on what will remain after resection, not what is removed. 6

Avoid routine biopsy: Lesions discovered at operation should not be biopsied, and excision of small atypical lesions should not be considered without discussion with the regional hepatobiliary unit. 1

Synchronous Metastases Management

• Generally avoid simultaneous resection of primary colorectal cancer and liver metastases 1
• Small accessible metastases detected preoperatively should be discussed with the liver center for consideration of combined resection 1
• After radical resection of primary tumor, patients with potentially resectable liver disease should be considered for liver resection before chemotherapy 1
• Unfavorable primary pathology (perforated tumor, extensive nodal involvement) warrants adjuvant chemotherapy prior to liver resection with restaging at three months 1