Initial Assessment of Resectability of Colorectal Cancer Liver Metastases Versus Clinical Outcome.

Background: Surgery improves long-term survival for resectable, liver-only metastatic colorectal cancer (mCRC). With no consensus definition of "resectable" disease, decisions regarding resectability are reliant on the expertise and judgement of the treating clinician working in consultation with a multidisciplinary team (MDT). This study examines the clinical outcome versus initial assessment of resectability in an Australian population with mCRC.

Patients and methods: Patients with liver-only mCRC diagnosed January 2009 to December 2022 were identified from the Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) registry. Patients were classified based on prospectively documented treatment assessment as "resectable," "potentially resectable," or "unresectable." The correlation between initial assessment of resectability and clinical outcome, and any impact of clinicopathologic factors were examined. Kaplan-Meier analysis assessed overall survival based on initial resectability assessment and resection status.

Results: Of 4437 patients with mCRC identified through TRACC, 1250 (28%) had liver-only disease at presentation, with 497 (43%), 277 (24%), and 374 (33%) classified as "unresectable," "potentially resectable," and "resectable," respectively. In total, 516 (41%) ultimately underwent surgical resection, including 30 (6%) of the "initially unresectable," 148 (53%) of the "potentially resectable," and 338 (90%) of the "resectable" at a median of 9.5, 5.9, and 2.4 months from the diagnosis of liver metastases, respectively. Resection in the "unresectable" patient population was associated with younger age (mean age 63 vs. 69, P = .0006), better performance status (ECOG 0-1 100% vs. 74%, P = .0017), and fewer comorbidities (Charlson index 0-3 in 73% vs. 53%, P = .0296) compared with no resection. Median overall survival was longer for resected versus nonresected patients across all categories: "unresectable" (59.2 vs. 17.6 months, P < .0001), "potentially resectable" (57.2 vs. 22.8 months, P < .0001), and "resectable" (108 vs. 55 months, P < .0001).

Conclusions: This real-world study demonstrates the potential for "initially unresectable" patients to become surgical candidates following systemic therapy, more likely in younger and fitter patients, with overall excellent survival outcomes in resected patients. This highlights the value of routine, repeated MDT assessments for patients with liver-only disease who are continuing to respond to systemic therapy, even for those initially considered never to be surgical candidates.