Preoperative 18F-FDG PET/computed tomography predicts survival following resection for colorectal liver metastases

The High Incidence of Occult Carcinoma in Total Hepatectomy Specimens of Patients Treated for Unresectable Colorectal Liver Metastases With Liver Transplant

OBJECTIVE

To describe the rate of occult carcinoma deposits in total hepatectomy specimens from patients treated with liver transplant (LT) for colorectal liver metastases (CRLM).

BACKGROUND

Previous studies have shown that patients with CRLM treated with systemic therapy demonstrate a high rate of complete radiographic response or may have disappearing liver metastases. However, this does not necessarily translate into a complete pathologic response, and residual invasive cancer may be found in up to 80% of the disappearing tumors after resection.

METHODS

Retrospective review of 14 patients who underwent LT for CRLM, at 2 centers. Radiographic and pathologic correlation of the number of tumors and their viability before and after LT was performed.

RESULTS

The median (interquartile range) number of tumors at diagnosis was 11 (4-23). The median number of chemotherapy cycles was 24 (16-37). Hepatic artery infusion was used in 5 patients (35.7%); 6 (42.9%) underwent surgical resection, and 5 (35.7%) received locoregional therapy. The indication for LT was unresectability in 8 patients (57.1%) and liver failure secondary to oncologic treatment in the remaining 6 (42.9%). Before LT, 7 patients (50%) demonstrated fluorodeoxyglucose-avid tumors and 7 (50%) had a complete radiographic response. Histopathologically, 11 patients (78.6%) had a viable tumor. Nine (64.2%) of the 14 patients were found to have undiagnosed metastases on explant pathology, with at least 22 unaccounted viable tumors before LT. Furthermore, 4 (57.1%) of the 7 patients who demonstrated complete radiographic response harbored viable carcinoma on explant pathology.

CONCLUSIONS

A complete radiographic response does not reliably predict a complete pathologic response. In patients with unresectable CRLM, total hepatectomy and LT represent a promising treatment options to prevent indolent disease progression from disappearing CRLM.

Liver transplantation in metastatic colorectal cancer: are we ready for it?

Colorectal cancer (CRC) is a prevalent disease worldwide, with more than 50% of patients developing metastases to the liver. Five-year overall survival remains modest among patients with metastatic CRC (mCRC) treated with conventional therapies however, liver transplantation in a highly selected population can improve clinical outcomes with an impressive 5-year overall survival of 83%. Despite liver transplantation appearing to be a promising therapeutical option for well-selected patients with mCRC with the liver-limited disease, these data come from small monocentric trials which included a heterogeneous population. Currently, several clinical trials are evaluating liver transplantation in this scenario, aiming for a more accurate patient selection by integrating liquid biopsy, tissue profiling, and nuclear medicine to the already known clinical biomarkers that eventually may lead to a survival improvement. In this paper, the clinical outcomes and inclusion criteria from the most relevant clinical trials and clinical series involving liver transplantation in patients with liver-limited disease colorectal cancer are reviewed as well as the trials currently recruiting.

PET-Uptake in Liver Metastases as Method to Predict Tumor Biological Behavior in Patients Transplanted for Colorectal Liver Metastases Developing Lung Recurrence

The objective of the study was to determine the impact of PET uptake on liver metastases on overall survival (OS) after resection of pulmonary metastases in patients who had received liver transplantation (LT) due to unresectable colorectal liver-only metastases. Resection of pulmonary colorectal metastases is controversial. Some hospitals offer this treatment to selected patients, whereas other hospitals do not perform the procedure in colorectal cancer patients who develop pulmonary metastases. All patients included in the LT studies who developed pulmonary metastases as first site of relapse, and had resection of these as first treatment, were included in this report. Metabolic tumor volume (MTV) in liver was derived from the pre-transplant PET examinations. OS from time of resection was calculated by the Kaplan−Meier method. Patients with low MTV (<70 cm3) had significantly longer OS from time of resection of pulmonary metastases compared to patients with high MTV (>70 cm3). Patients with low MTV in the liver had 10-year OS from time of pulmonary resections of 86%. Liver MTV values from pre-transplant PET examinations may predict long OS in colorectal cancer patients with a resection of pulmonary metastases developing after LT. Thus, in selected colorectal cancer patients developing pulmonary metastases resection of these metastases should be the treatment of choice.

Metabolic tumor volume predicts long-term survival after transplantation for unresectable colorectal liver metastases: 15 years of experience from the SECA study

Objective

To report 15 years of experience with metabolic tumor volume (MTV) of liver metastases from the preoperative ¹⁸F-FDG PET/CT to predict long-term survival after liver transplantation (LT) for unresectable colorectal liver metastases (CRLM).

Methods

The preoperative ¹⁸F-FDG PET/CT from all SECA 1 and 2 patients was evaluated. MTV was obtained from all liver metastases. The patients were divided into one group with low MTV (< 70 cm³) and one group with high MTV (> 70 cm³) based on a receiver operating characteristic analysis. Overall survival (OS), disease-free survival (DFS) and post recurrence survival (PRS) for patients with low versus high MTV were compared using the Kaplan–Meier method and log rank test. Clinopathological features between the two groups were compared by a nonparametric Mann–Whitney U test for continuous and Fishers exact test for categorical data.

Results

At total of 40 patients were included. Patients with low MTV had significantly longer OS (p < 0.001), DFS (p < 0.001) and PRS (p = 0.006) compared to patients with high values. The patients with high MTV had higher CEA levels, number of liver metastases, size of the largest liver metastasis, N-stage, number of chemotherapy lines and more frequently progression of disease at LT compared to the patients with low MTV.

Conclusion

MTV of liver metastases is highly predictive of long-term OS, DFS and PRS after LT for unresectable CRLM and should be implemented in risk stratification prior to LT.

Liver transplantation for colorectal secondaries: on the way to validation

PURPOSE OF REVIEW

Liver transplantation for nonresectable colorectal liver metastases (CRLMs) is an emerging field within transplant oncology. This review summarizes recent developments within this field.

RECENT FINDINGS

More stringent selection criteria can yield 5-year survival rates that are similar to conventional indications for liver transplantation. Response to chemotherapy, low carcinoembryonic antigen levels, limited tumor volume and stable disease with observation time exceeding 12 months are fundamental requirements in this context. Radiomic analysis of pre transplant PET/computed tomography scans to determine metabolic tumor volume (MTV) in the liver seems particularly promising with regards to prediction of a favorable tumor biology. MTV values below 70 cm3 are associated with excellent long-term survival after transplantation, whereas the MTV threshold for liver resection seem far smaller. Recent studies put into question whether technical nonresectability per se is a valid inclusion criterion for liver transplantation. In patients with high hepatic tumor burden, but otherwise favorable prognostic features as assessed by the Oslo score, liver transplantation could possibly give a clinically relevant survival benefit compared with liver resection.

SUMMARY

Liver transplantation is feasible treatment option in highly selected patients with nonresectable CRLMs. Robust and stringent selection criteria should be applied according to international consensus guidelines.

Survival after liver resection and liver transplantation for colorectal liver metastases: a comparative analysis stratified by metabolic tumor volume assessed by 18F-FDG PET/CT

BACKGROUND

Many patients undergoing resection for colorectal liver metastases (CRLM) recur with poor survival. Overall survival (OS) following liver transplantation (LT) for CRLM is reported to be about 80% at 5 years. In this study, survival following resection versus transplantation for CRLM in patients with moderate (6-70 cm³) metabolic tumor volume (MTV) from the preoperative positron emission tomography (PET) was compared.

METHODS

Disease-free survival (DFS), OS and post recurrence survival (PRS) following resection (n = 18) and LT (n = 12) was compared by using the Kaplan Meier method and log rank test for patients with moderate MTV.

RESULTS

Patients undergoing LT had unresectable metastases, significantly lower age, higher tumor burden score and number of liver metastases, longer time from diagnosis to surgery, and more patients received neoadjuvant chemotherapy. OS at 5 years was 39% in the resection group and 83% in the LT group (P = 0.012). PRS was significantly improved in patients treated with LT compared to resection with 71% alive at 5 years from recurrence compared to 17% in the resection group (P = 0.017).

CONCLUSION

LT for selected patients seems to be superior to resection as treatment for CRLM for patients with moderate MTV.

Prognostic Significance of Pretreatment 18F-FDG PET/CT Volumetric Parameters in Patients With Colorectal Liver Metastasis: A Systematic Review and Meta-analysis

PURPOSE

Colorectal liver metastasis (CRLM) remains a clinical challenge due to the lack of reliable prognostic parameters. We performed a systematic review and meta-analysis of the prognostic value of pretreatment 18F-FDG PET/CT volumetric parameters for hepatic metastatic lesions (HMLs) in patients with CRLM.

METHODS

A systematic search was performed using the following combination of keywords: CRLM, FDG, PET, and prognosis. The inclusion criteria were studies using 18F-FDG PET/CT as an imaging tool before treatment, including volumetric parameters (metabolic tumor volume [MTV] and total lesion glycolysis [TLG]) for HMLs, and reported survival data. Event-free survival and overall survival were considered as survival markers. The effect on survival was determined by the effect size of the hazard ratio (HR) with 95% confidence interval (CI).

RESULTS

Our systematic search identified 668 records, and a total of 10 studies comprising 494 patients were included. The pooled HRs of the prognostic value of the MTV and TLG for event-free survival were 1.55 (95% CI, 1.21-1.99; P = 0.0006) and 1.64 (95% CI, 1.23-2.19; P = 0.0009) with significance, respectively. The pooled HRs of the prognostic value of the MTV and TLG for overall survival were 1.72 (95% CI, 1.32-2.23; P < 0.0001) and 2.09 (95% CI, 1.48-2.96; P < 0.0001) with significance, respectively.

CONCLUSIONS

Higher MTV and TLG for HMLs before treatment were identified as worse prognostic parameters in patients with CRLM. The MTV and TLG of 18F-FDG PET/CT could be used as predictors of prognosis.