Clinical utility of PET-CT in the management of colorectal liver metastases.

Abstract

e15547 Background: Patients with colorectal cancer liver metastases (CRCLM) may be considered for potentially curative liver resection. A critical determinant of benefit from surgery is the absence of occult extrahepatic disease, particularly nodal involvement, which may not be detected on conventional imaging. Proceeding to laparotomy in such patients confers limited survival benefit while incurring significant morbidity. Although PET-CT is not routinely recommended in international guidelines for pre-operative assessment in CRCLM, emerging evidence suggests a role in improved patient selection. This study aimed to evaluate the impact of pre-operative PET-CT on surgical decision-making in a large real-world cohort. Methods: Patients with CRCLM discussed at The Mater Misericordiae University Hospital multidisciplinary team (MDT) meeting from 2020–2024 were included. During this period, over 8,700 MDT cases were reviewed, identifying 584 suitable patients. Clinical, radiological, and operative data were extracted, including MDT history, PET-CT results, surgical intent, and operative outcomes. Abandoned surgery was defined as laparotomy in which resection was not performed due to intra-operative findings. The primary outcome was the proportion of abandoned surgeries among patients who underwent pre-operative PET-CT compared with those who did not. Group comparisons were performed using Fisher’s exact test, with odds ratios reported. Overall survival (OS) was calculated from the date of surgery using Kaplan–Meier methods and compared using Cox proportional hazards regression. Results: Of the 584 patients included, 273 underwent surgery with curative intent, while 311 did not proceed to surgery. Among patients who did not undergo surgery, 186(59.8%) had previously undergone PET-CT. Of the 273 patients who proceeded to surgery, 141(51.6%) underwent pre-operative PET-CT. Sixteen surgical procedures were abandoned intraoperatively. This occurred in 12 patients staged without, and 4 patients with PET-CT staging, corresponding to abandonment rates of approximately 9% and 2%, respectively (p = 0.002; OR 0.28). Among patients who underwent resection, median OS from the date of surgery was 55.2 months in the PET-CT group compared with 37.2 months in the non-PET group; this difference did not reach statistical significance (HR 0.61, 95% CI 0.33–1.10; p = 0.10). Conclusions: In this large cohort of patients with CRCLM, pre-operative PET-CT was associated with a significantly lower rate of abandoned surgery, without a statistically significant difference in post-resection overall survival. These findings support the role of PET-CT in improving patient selection by identifying occult disease not evident on standard imaging, thus reducing non-therapeutic laparotomy and associated morbidity. Further prospective studies are warranted to define subgroups most likely to benefit from pre-operative PET-CT.