Locoregional Therapies for Colorectal Cancer Liver Metastases: Options Beyond Resection

Determinants of Metastatic Colorectal Cancer With Permanent Liver- Limited Disease

Colorectal cancer (CRC) is a complex and genetically heterogeneous disease presenting a specific metastatic pattern, with the liver being the most common site of metastasis. Around 20%-25% of patients with CRC will develop exclusively hepatic metastatic disease throughout their disease history. With its specific characteristics and therapeutic options, liver-limited disease (LLD) should be considered as a specific entity. The identification of these patients is particularly relevant in view of the growing interest in liver transplantation in selected patients with advanced CRC. Identifying why some patients will develop only LLD remains a challenge, mainly because of a lack of a systemic understanding of this complex and interlinked phenomenon given that cancer has traditionally been investigated according to distinct physiological compartments. Recently, multidisciplinary efforts and new diagnostic tools have made it possible to study some of these complex issues in greater depth and may help identify targets and specific treatment strategies to benefit these patients. In this review we analyze the underlying biology and available tools to help clinicians better understand this increasingly common and specific disease.

Phase I trial of single-photon emission computed tomography-guided liver-directed radiotherapy for patients with low functional liver volume

BACKGROUND

Traditional constraints specify that 700 cc of liver should be spared a hepatotoxic dose when delivering liver-directed radiotherapy to reduce the risk of inducing liver failure. We investigated the role of single-photon emission computed tomography (SPECT) to identify and preferentially avoid functional liver during liver-directed radiation treatment planning in patients with preserved liver function but limited functional liver volume after receiving prior hepatotoxic chemotherapy or surgical resection.

METHODS

This phase I trial with a 3 + 3 design evaluated the safety of liver-directed radiotherapy using escalating functional liver radiation dose constraints in patients with liver metastases. Dose-limiting toxicities were assessed 6-8 weeks and 6 months after completing radiotherapy.

RESULTS

All 12 patients had colorectal liver metastases and received prior hepatotoxic chemotherapy; 8 patients underwent prior liver resection. Median computed tomography anatomical nontumor liver volume was 1584 cc (range = 764-2699 cc). Median SPECT functional liver volume was 1117 cc (range = 570-1928 cc). Median nontarget computed tomography and SPECT liver volumes below the volumetric dose constraint were 997 cc (range = 544-1576 cc) and 684 cc (range = 429-1244 cc), respectively. The prescription dose was 67.5-75 Gy in 15 fractions or 75-100 Gy in 25 fractions. No dose-limiting toxicities were observed during follow-up. One-year in-field control was 57%. One-year overall survival was 73%.

CONCLUSION

Liver-directed radiotherapy can be safely delivered to high doses when incorporating functional SPECT into the radiation treatment planning process, which may enable sparing of lower volumes of liver than traditionally accepted in patients with preserved liver function.

TRIAL REGISTRATION

NCT02626312.

Irreversible Electroporation of the Hepatobiliary System: Current Utilization and Future Avenues

Liver cancer remains a leading cause of cancer-related deaths worldwide despite numerous advances in treatment. While surgical resection remains the gold standard for curative treatment, it is only possible for a minority of patients. Thermal ablation is an effective option for the treatment of smaller tumors; however, its use is limited to tumors that are not located in proximity to sensitive structures due to the heat sink effect and the potential of thermal damage. Irreversible electroporation (IRE) is a non-thermal ablative modality that can deliver targeted treatment and the effective destruction of tumors that are in close proximity to or even surrounding vascular or biliary ducts with minimal damage to these structures. IRE produces short pulses of high-frequency energy which opens pores in the lipid bilayer of cells leading to apoptosis and cell death. IRE has been utilized clinically for over a decade in the treatment of liver cancers with multiple studies documenting an acceptable safety profile and high efficacy rates.

Baseline Tumor Size as Prognostic Index in Patients With Advanced Solid Tumors Receiving Experimental Targeted Agents

BACKGROUND

Baseline tumor size (BTS) has been associated with outcomes in patients with cancer treated with immunotherapy. However, the prognostic impact of BTS on patients receiving targeted therapies (TTs) remains undetermined.

METHODS

We reviewed data of patients with advanced solid tumors consecutively treated within early-phase clinical trials at our institution from 01/2014 to 04/2021. Treatments were categorized as immunotherapy-based or TT-based (biomarker-matched or not). BTS was calculated as the sum of RECIST1.1 baseline target lesions.

RESULTS

A total of 444 patients were eligible; the median BTS was 69 mm (IQR 40-100). OS was significantly longer for patients with BTS lower versus higher than the median (16.6 vs. 8.2 months, P < .001), including among those receiving immunotherapy (12 vs. 7.5 months, P = .005). Among patients receiving TT, lower BTS was associated with longer PFS (4.7 vs. 3.1 months, P = .002) and OS (20.5 vs. 9.9 months, P < .001) as compared to high BTS. However, such association was only significant among patients receiving biomarker-matched TT, with longer PFS (6.2 vs. 3.3 months, P < .001) and OS (21.2 vs. 6.7 months, P < .001) in the low-BTS subgroup, despite a similar ORR (28% vs. 22%, P = .57). BTS was not prognostic among patients receiving unmatched TT, with similar PFS (3.7 vs. 4.4 months, P = .30), OS (19.3 vs. 11.8 months, P = .20), and ORR (33% vs. 28%, P = .78) in the 2 BTS groups. Multivariate analysis confirmed that BTS was independently associated with PFS (P = .03) and OS (P < .001) but not with ORR (P = .11).

CONCLUSIONS

Higher BTS is associated with worse survival outcomes among patients receiving biomarker-matched, but not biomarker-unmatched TT.

Efficacy of CalliSpheres® microspheres versus conventional transarterial chemoembolization in the treatment of refractory colorectal cancer liver metastasis

OBJECTIVE

CalliSpheres® is a microsphere that is already widely used for primary liver cancer treatment; however, its application in colorectal cancer liver metastasis (CRLM) is limited. The current study aimed to investigate the efficacy of CalliSpheres® drug-eluting bead (DEB) transarterial chemoembolization (TACE) therapy versus (vs.) conventional cTACE therapy in treating refractory CRLM (RCRLM) patients.

METHODS

Twenty-two RCRLM patients who underwent CalliSpheres® DEB-TACE therapy (n = 11) or cTACE therapy (n = 11) were retrospectively analyzed. Data on clinical response, progression-free survival (PFS) and overall survival (OS) were retrieved.

RESULTS

The objective response rate (36.4% vs. 18.2%, P = 0.338) and disease control rate (81.8% vs. 54.4%, P = 0.170) were both numerically (but not statistically) higher in the DEB-TACE group than in the cTACE group. Meanwhile, PFS was prolonged in the DEB-TACE group compared with the cTACE group [median: 12.0 (95% CI: 5.6-18.4) vs. 4.0 (95% CI: 0.9-7.1) months, P = 0.018]; OS was also longer in the DEB-TACE group compared with the cTACE group [median: 24.0 (95% CI: 18.3-29.7) vs. 14.0 (95% CI: 7.1-20.9) months, P = 0.040]. In addition, after adjustment by multivariate Cox analyses, DEB-TACE was superior to cTACE independently regarding PFS (HR: 0.110, 95% CI: 0.026-0.463, P = 0.003) and OS (HR: 0.126, 95% CI: 0.028-0.559, P = 0.006).

CONCLUSION

CalliSpheres® DEB-TACE therapy may prolong survival profile than cTACE therapy in RCRLM patients, while further validation is still needed.

Current Surgical Management Strategies for Colorectal Cancer Liver Metastases

Simple Summary

Colorectal cancer is one of the most common cancer diagnoses in the world. At least half of patients diagnosed with colorectal cancer will develop metastatic disease, with most being identified in the liver. Surgical resection of colorectal liver metastases (CRLM) is potentially curative. Surgical resection of CRLM, however, remains underutilized despite the continued expansion of operative strategies available. This is likely due to differing views on resectability. Resectability is a surgical assessment, and the classification of CRLM as unresectable should only be made by an experienced hepatobiliary surgeon. Obtaining a surgical evaluation at the time of liver metastasis discovery may help mitigate the challenge of assessing resectability and the determination of potential operative time windows within current multimodal management strategies. The aim of this review is to help facilitate discussions surrounding resectability as well as the timing and sequencing of both surgical and non-surgical therapies.

Abstract

Colorectal cancer is the third most common cancer diagnosis in the world, and the second most common cause of cancer-related deaths. Despite significant progress in management strategies for colorectal cancer over the last several decades, metastatic disease remains difficult to treat and is often considered incurable. However, for patients with colorectal liver metastases (CRLM), surgical resection offers the best opportunity for survival, can be curative, and remains the gold standard. Unfortunately, surgical treatment options are underutilized. Misperceptions regarding resectable and unresectable CRLM likely play a role in this. The assessment of factors that impact resectability status like medical fitness, technical considerations, and disease biology can be difficult, necessitating careful multidisciplinary input and discussion. The identification of ideal operative time windows that align with the multimodal management of these patients can also be perplexing. For all patients with CRLM it may therefore be advantageous to obtain surgical evaluation at the time of discovering liver metastases to mitigate these challenges and minimize the risk of undertreatment. In this review we summarize current surgical management strategies for CRLM and discuss factors to be considered when determining resectability.

Radioembolization With Chemotherapy for Colorectal Liver Metastases: A Randomized, Open-Label, International, Multicenter, Phase III Trial

PURPOSE

To study the impact of transarterial Yttrium-90 radioembolization (TARE) in combination with second-line systemic chemotherapy for colorectal liver metastases (CLM).

METHODS

In this international, multicenter, open-label phase III trial, patients with CLM who progressed on oxaliplatin- or irinotecan-based first-line therapy were randomly assigned 1:1 to receive second-line chemotherapy with or without TARE. The two primary end points were progression-free survival (PFS) and hepatic PFS (hPFS), assessed by blinded independent central review. Random assignment was performed using a web- or voice-based system stratified by unilobar or bilobar disease, oxaliplatin- or irinotecan-based first-line chemotherapy, and KRAS mutation status.

RESULTS

Four hundred twenty-eight patients from 95 centers in North America, Europe, and Asia were randomly assigned to chemotherapy with or without TARE; this represents the intention-to-treat population and included 215 patients in the TARE plus chemotherapy group and 213 patients in the chemotherapy alone group. The hazard ratio (HR) for PFS was 0.69 (95% CI, 0.54 to 0.88; 1-sided P = .0013), with a median PFS of 8.0 (95% CI, 7.2 to 9.2) and 7.2 (95% CI, 5.7 to 7.6) months, respectively. The HR for hPFS was 0.59 (95% CI, 0.46 to 0.77; 1-sided P < .0001), with a median hPFS of 9.1 (95% CI, 7.8 to 9.7) and 7.2 (95% CI, 5.7 to 7.6) months, respectively. Objective response rates were 34.0% (95% CI, 28.0 to 40.5) and 21.1% (95% CI, 16.2 to 27.1; 1-sided P = .0019) for the TARE and chemotherapy groups, respectively. Median overall survival was 14.0 (95% CI, 11.8 to 15.5) and 14.4 months (95% CI, 12.8 to 16.4; 1-sided P = .7229) with a HR of 1.07 (95% CI, 0.86 to 1.32) for TARE and chemotherapy groups, respectively. Grade 3 adverse events were reported more frequently with TARE (68.4% v 49.3%). Both groups received full chemotherapy dose intensity.

CONCLUSION

The addition of TARE to systemic therapy for second-line CLM led to longer PFS and hPFS. Further subset analyses are needed to better define the ideal patient population that would benefit from TARE.