Colorectal liver metastases: making the unresectable resectable using irreversible electroporation for microscopic positive margins - a case report

Complete Response With Cetuximab-Based Treatment of Metastatic Colorectal Cancers: Two Case Reports and Literature Review

Metastases typically develop before diagnosis and during the treatment of colorectal cancers, while patients with metastatic colorectal cancers (mCRCs) currently have a poor prognosis. In terms of surgical approaches, adjuvant therapies, and targeted therapies, the treatment of mCRCs has had numerous recent advances. As a targeted agent widely used in mCRCs, cetuximab-based treatment is still under dispute due to its side effects and unstable effect. We present two mCRC cases treated with cetuximab-based therapy, of which two patients achieved complete response and without recurrence for over 22 and 84 months, respectively. To better understand the drug usage, we also reviewed the recent achievements and usage precautions of cetuximab in mCRCs. Present and many previous observations support that cetuximab might be a referred drug in the first-line chemotherapy of mCRCs with wild-type RAS and BRAF and proficient mismatch repair.

Hepatic metastasis from colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers in the world. About two third of patients with CRC will develop distant recurrence at some point in time. Liver is the most common site where distant metastasis takes place. While the overall survival (OS) of patients with metastatic CRC was poor about 3 decades ago, there has been tremendous improvement in this area in the recent years. With the advent of effective systemic chemotherapy and biologic agents and better understanding of the biological behaviour of the tumour, aggressive treatment strategies such as metastatectomy of the liver metastases (or lung metastases) are now acceptable. More importantly, it has transformed the way how stage IV CRCs are being managed. From predominantly palliative as the primary aim, a comprehensive multidisciplinary approach is now the mainstay of treatment with very successful outcomes. Combination of systemic therapies with liver resection has been shown to be effective in providing promising survival benefits. In addition, other adjunctive modalities in targeting the liver metastases such as ablation, combining resection and ablation, transarterial chemoembolization, stereotactic body radiotherapy (SBRT), hepatic artery perfusion, etc. have also been demonstrated variable outcome in treating colorectal liver metastasis (CRLM). Very recently, transplant oncologists have also explored using liver transplantation as a treatment modality for unresectable CRLM, which has demonstrated very good long-term survival in well selected cases. The new paradigm in the treatment of metastatic CRC has dawned.

Peri-tumoral Metallic Implants Reduce the Efficacy of Irreversible Electroporation for the Ablation of Colorectal Liver Metastases

PURPOSE

To evaluate the effect of peri-tumoral metallic implants (MI) on the safety and efficacy of percutaneous irreversible electroporation (IRE) of colorectal liver metastasis (CRLM).

MATERIALS AND METHODS

In this retrospective study, 25 patients (12 women, 13 men; MI: 13, no MI: 12) were treated for 29 CRLM. Patient characteristics, tumor location and size, treatment parameters and the presence of MI were evaluated as determinants of local tumor progression (LTP) with the competing risks model (univariate and multivariate analyses). Patient-specific computer models were created to examine the effect of the MI on the electric field used to induce IRE, probability of cell kill and potential thermal effects.

RESULTS

Patients had a median follow-up of 25 months, during which no IRE-related major complications were reported. Univariate analysis showed that tumor size (> 2 cm), probe spacing (> 20 mm) and the presence of MI (p < 0.05) were significant predictors of time to LTP, but only the latter was found to be an independent predictor on multivariate analysis (sub-hazard ratio = 6.5; [95% CI 1.99, 21.4]; p = 0.002). The absence of peri-tumoral MI was associated with higher progression-free survival at 12 months (92.3% [56.6, 98.9] vs 12.5% [2.1, 32.8]). Computer simulations indicated significant distortions and reduction in electric field strength near MI, which could have contributed to under-treatment of the tumor.

CONCLUSIONS

Peri-tumoral MI increases the risk of treatment failure following IRE of CRLM.

Impact of surgical margin clearance for resection of secondary hepatic malignancies

Over the past several decades, there has been increasing discussion regarding the optimal management of secondary liver malignancies. Traditionally, resection has only been recommended if it could be accomplished with negative microscopic margins of at least 10 mm. However, many investigators have pushed this limit to offer resection to patients with narrower margins. We review the data regarding the impact of margin clearance on outcomes for patients undergoing hepatic metastasectomy.