A new sequential treatment strategy for multiple colorectal liver metastases: Planned incomplete resection and postoperative completion ablation for intentionally-untreated tumors under guidance of cross-sectional imaging

Hybrid operating room applications for precision hepatobiliary surgery: A narrative review

This review summarizes the key applications of a hybrid operating room (HOR) in hepatobiliary surgery and explores the advantages, limitations, and future directions of its utilization. A comprehensive literature search was conducted in PubMed to identify articles reporting on the utilization of HORs in liver surgery. So far, the HOR has been limitedly applied in hepatobiliary surgery. It can offer an optimal environment for combining radiological and surgical interventions and for performing image-guided surgical navigation.

Local Therapy Improves Survival for Early Recurrence After Resection of Colorectal Liver Metastases

BACKGROUND

Early recurrence following hepatectomy for colorectal liver metastases (CLM) is associated with worse survival; yet, impact of further local therapy is unclear. We sought to evaluate whether local therapy benefits patients with early recurrence following hepatectomy for CLM.

METHODS

Clinicopathologic and survival outcomes of patients managed with hepatectomy for CLM (1/2001-12/2020) were queried from a prospectively maintained database. Timing of recurrence was stratified as early (recurrence-free survival [RFS] < 6 months), intermediate (RFS 6-12 months), and later (RFS > 12 months). Local therapy was defined as ablation, resection, or radiation.

RESULTS

Of 671 patients, 541 (81%) recurred with 189 (28%) early, 180 (27%) intermediate, and 172 (26%) later recurrences. Local therapy for recurrence resulted in improved survival, regardless of recurrence timing (early 78 vs. 32 months, intermediate 72 vs. 39 months, later 132 vs. 65 months, all p < 0.001). Following recurrence, treatment with local therapy (hazard ratio [HR] = 0.24), liver and extrahepatic recurrence (HR = 1.81), RAS + TP53 co-mutation (HR = 1.52), and SMAD4 mutation (HR = 1.92) were independently associated with overall survival (all p ≤ 0.002). Among patients with recurrence treated by local therapy, patients older than 65 years (HR 1.79), liver and extrahepatic recurrence (HR 2.05), primary site or other recurrence (HR 1.90), RAS-TP53 co-mutation (HR 1.63), and SMAD4 mutation (HR 2.06) had shorter post-local therapy survival (all p ≤ 0.04).

CONCLUSIONS

While most patients recur after hepatectomy for CLM, local therapy may result in long-term survival despite early recurrence. Somatic mutational profiling may help to guide the multidisciplinary consideration of local therapy after recurrence.

Optimizing Treatment Strategy for Oligometastases/Oligo-Recurrence of Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer, and nearly half of CRC patients experience metastases. Oligometastatic CRC represents a distinct clinical state characterized by limited metastatic involvement, demonstrating a less aggressive nature and potentially improved survival with multidisciplinary treatment. However, the varied clinical scenarios giving rise to oligometastases necessitate a precise definition, considering primary tumor status and oncological factors, to optimize treatment strategies. This review delineates the concepts of oligometastatic CRC, encompassing oligo-recurrence, where the primary tumor is under control, resulting in a more favorable prognosis. A comprehensive examination of multidisciplinary treatment with local treatments and systemic therapy is provided. The overarching objective in managing oligometastatic CRC is the complete eradication of metastases, offering prospects of a cure. Essential to this management approach are local treatments, with surgical resection serving as the standard of care. Percutaneous ablation and stereotactic body radiotherapy present less invasive alternatives for lesions unsuitable for surgery, demonstrating efficacy in select cases. Perioperative systemic therapy, aiming to control micrometastatic disease and enhance local treatment effectiveness, has shown improvements in progression-free survival through clinical trials. However, the extension of overall survival remains variable. The review emphasizes the need for further prospective trials to establish a cohesive definition and an optimized treatment strategy for oligometastatic CRC.

A prospective multicentre trial on survival after Microwave Ablation VErsus Resection for Resectable Colorectal liver metastases (MAVERRIC)

AIM

This multi-centre prospective cohort study aimed to investigate non-inferiority in patients' overall survival when treating potentially resectable colorectal cancer liver metastasis (CRLM) with stereotactic microwave ablation (SMWA) as opposed to hepatic resection (HR).

METHODS

Patients with no more than 5 CRLM no larger than 30 mm, deemed eligible for both SMWA and hepatic resection at the local multidisciplinary team meetings, were deliberately treated with SMWA (study group). The contemporary control group consisted of patients with no more than 5 CRLM, none larger than 30 mm, treated with HR, extracted from a prospectively maintained nationwide Swedish database. After propensity-score matching, 3-year overall survival (OS) was compared as the primary outcome using Kaplan-Meier and Cox regression analyses.

RESULTS

All patients in the study group (n = 98) were matched to 158 patients from the control group (mean standardised difference in baseline covariates = 0.077). OS rates at 3 years were 78% (Confidence interval [CI] 68-85%) after SMWA versus 76% (CI 69-82%) after HR (stratified Log-rank test p = 0.861). Estimated 5-year OS rates were 56% (CI 45-66%) versus 58% (CI 50-66%). The adjusted hazard ratio for treatment type was 1.020 (CI 0.689-1.510). Overall and major complications were lower after SMWA (percentage decrease 67% and 80%, p < 0.01). Hepatic retreatments were more frequent after SMWA (percentage increase 78%, p < 0.01).

CONCLUSION

SMWA is a valid curative-intent treatment alternative to surgical resection for small resectable CRLM. It represents an attractive option in terms of treatment-related morbidity with potentially wider options regarding hepatic retreatments over the future course of disease.

Locoregional treatment for colorectal liver metastases aiming for precision medicine

In patients with colorectal liver metastases (CLM), surgery is potentially curative. The use of novel surgical techniques and complementary percutaneous ablation allows for curative-intent treatment even in marginally resectable cases. Resection is used as part of a multidisciplinary approach, which for nearly all patients will include perioperative chemotherapy. Small CLM can be treated with parenchymal-sparing hepatectomy (PSH) and/or ablation. For small CLM, PSH results in better survival and higher rates of resectability of recurrent CLM than non-PSH. For patients with extensive bilateral distribution of CLM, two-stage hepatectomy or fast-track two-stage hepatectomy is effective. Our increasing knowledge of genetic alterations allows us to use them as prognostic factors alongside traditional risk factors (e.g. tumor diameter and tumor number) to select patients with CLM for resection and guide surveillance after resection. Alteration in RAS family genes (hereafter referred to as "RAS alteration") is an important negative prognostic factor, as are alterations in the TP53, SMAD4, FBXW7, and BRAF genes. However, APC alteration appears to improve prognosis. RAS alteration, increased number and diameter of CLM, and primary lymph node metastasis are well-known risk factors for recurrence after CLM resection. In patients free of recurrence 2 y after CLM resection, only RAS alteration is associated with recurrence. Thus, surveillance intensity can be stratified by RAS alteration status after 2 y. Novel diagnostic instruments and tools, such as circulating tumor DNA, may lead to further evolution of patient selection, prognostication, and treatment algorithms for CLM.

Local Treatments in the Unresectable Patient with Colorectal Cancer Metastasis: A Review from the Point of View of the Medical Oncologist

For patients with isolated liver metastases from colorectal cancer who are not candidates for potentially curative resections, non-surgical local treatments may be useful. Non-surgical local treatments are classified according to how the treatment is administered. Local treatments are applied directly on hepatic parenchyma, such as radiofrequency, microwave hyperthermia and cryotherapy. Locoregional therapies are delivered through the hepatic artery, such as chemoinfusion, chemoembolization or selective internal radiation with Yttrium 90 radioembolization. The purpose of this review is to describe the different interventional therapies that are available for these patients in routine clinical practice, the most important clinical trials that have tried to demonstrate the effectiveness of each therapy and recommendations from principal medical oncologic societies.

Image-Guided Ablation for Colorectal Liver Metastasis: Principles, Current Evidence, and the Path Forward

Image-guided ablation can provide effective local tumor control in selected patients with CLM. A randomized controlled trial suggested that radiofrequency ablation combined with systemic chemotherapy resulted in a survival benefit for patients with unresectable CLM, compared to systemic chemotherapy alone. For small tumors, ablation with adequate margins can be considered as an alternative to resection. The improvement of ablation technologies can allow the treatment of tumors close to major vascular structures or bile ducts, on which the applicability of thermal ablation modalities is challenging. Several factors affect the outcomes of ablation, including but not limited to tumor size, number, location, minimal ablation margin, RAS mutation status, prior hepatectomy, and extrahepatic disease. Further understanding of the impact of tumor biology and advanced imaging guidance on overall patient outcomes might help to tailor its application, and improve outcomes of image-guided ablation.

Prognostic and Therapeutic Implications of Tumor Biology, Including Gene Alterations, in Colorectal Liver Metastases

BACKGROUND

For patients with colorectal liver metastases (CLM), the combination of surgical resection with other therapeutic options is essential. This article shows how recent advances in knowledge of tumor biology, including genetic alterations, affect the choice of therapeutic approach for patients with CLM.

METHODS

We reviewed the literature on recent advances in knowledge about CLM tumor biology including genetic profiles, clinical risk score models for CLM, preoperative therapy for CLM, and liver-directed therapy for CLM.

RESULTS

Studies showed that RAS alteration is a negative prognostic factor in addition to traditional clinical risk factors (e.g., larger diameter and higher number of CLM, spread of the primary tumor to regional lymph nodes). Although the response to preoperative chemotherapy is an important predictor of survival, poor response is not a contraindication to surgical resection. The combination of surgical therapy and percutaneous ablation can be considered in marginally resectable cases; however, a wider ablation margin is required for RAS-mutant CLM. More recently, genetic analysis using next-generation sequencing showed the negative prognostic impact of alterations in TP53, SMAD4, FBXW7, and RAS/BRAF in patients with CLM. In RAS-mutant CLM, intensive follow-up is required in patients who remain recurrence free 2 years after surgery.

DISCUSSION

In patients with CLM, RAS mutation status is important in predicting postoperative survival, selecting the treatment approach, and tailoring postoperative follow-up. In addition, more recent genetic analyses of CLM have identified additional predictors of survival.

Diagnostic and procedural intraoperative ultrasound: technique, tips and tricks for optimizing results

Intraoperative ultrasound (IOUS) is a valuable adjunctive tool that can provide real-time diagnostic information in surgery that has the potential to alter patient management and decrease complications. Lesion localization, characterization and staging can be performed, as well as surveying for additional lesions and metastatic disease. IOUS is commonly used in the liver for hepatic metastatic disease and hepatocellular carcinoma, in the pancreas for neuroendocrine tumors, and in the kidney for renal cell carcinoma. IOUS allows real-time evaluation of vascular patency and perfusion in organ transplantation and allows for early intervention for anastomotic complications. It can also be used to guide intraoperative procedures such as biopsy, fiducial placement, radiation, or ablation. A variety of adjuncts including microbubble contrast and elastography may provide additional information at IOUS. It is important for the radiologist to be familiar with the available equipment, common clinical indications, technique, relevant anatomy and intraoperative imaging appearance to optimize performance of this valuable imaging modality.