A new study published in Digestive and Liver Disease indicates that contrast-enhanced intraoperative ultrasound (CE-IOUS) can significantly improve outcomes for patients undergoing liver resection for colorectal cancer liver metastases (CRLM). The research highlights the potential of CE-IOUS to reduce intrahepatic recurrence and improve hepatic recurrence-free survival (HRFS) in this patient population.
Enhanced Detection with CE-IOUS
The study compared the efficacy of CE-IOUS to standard intraoperative ultrasound (IOUS) in detecting CRLMs. Results showed that CE-IOUS had a 100% detection rate of CRLMs identified before the operation, compared to 89.8% for IOUS alone. Notably, CE-IOUS detected 68.3% of CRLMs, while IOUS detected only 51.7%. The ability of CE-IOUS to identify disappearing liver metastases was also significant, with detection in 60 of 63 patients in the CE-IOUS group.
Improved Hepatic Recurrence-Free Survival
Patients who underwent CE-IOUS had improved HRFS rates compared to those who underwent IOUS only. At 6 months, the HRFS rate was 85% in the CE-IOUS group compared to 67% in the IOUS group. At 12 months, the HRFS rates were 63% and 49%, respectively. Early hepatic recurrence was observed in 19.4% of the CE-IOUS group versus 31.3% of the IOUS group.
Study Details and Patient Characteristics
The study included 130 patients diagnosed with unresectable CRLM who underwent liver metastasis resection. Patients were included if they were 18 years or older, had histopathologically confirmed CRC, and had abdominal CT and MRI for their liver conducted at the center before chemotherapy. All CRLMs were amenable to microwave ablation or surgical resection. Patients were excluded for reasons including positive margins after liver resection, an excessive number of hepatic metastases, allergy to eggs, pregnancy, previous local ablation or surgery, no neoadjuvant or adjuvant chemotherapy, or no imaging either before chemotherapy or at follow-up.
The median follow-up time for the overall group was 24.0 months. The IOUS group had a follow-up of 39.2 months, while the CE-IOUS group had a follow-up of 18.5 months. The death rate in the IOUS group was 26.9% compared to 6.3% in the CE-IOUS group, although the difference in overall survival between the two groups was not statistically significant.
Clinical Implications and Limitations
These findings suggest that CE-IOUS can help reduce the risk of intrahepatic recurrence in patients with CRLM by detecting lingering nodules and tumors. The study authors conclude that CE-IOUS can improve the HRFS of these individuals overall.
Limitations of the study include its retrospective nature, which made matching of metastasis location and number on imaging impossible. The study also focused only on intrahepatic recurrence and had a relatively short follow-up period. Potential selection bias and differences in operation times between the two study groups were also noted. The number of included cases was limited due to strict inclusion criteria.
