Colorectal cancer (CRC) is a significant global health issue, especially due to the high rate of liver metastases [1]. While surgical resection is the preferred curative treatment, many patients are ineligible due to unresectable disease or recurrences, leading to limited options and poor prognoses. Recently, liver transplantation (LT) has emerged as a promising curative alternative for select patients with advanced CRC and liver metastases. Although traditionally used for end-stage liver disease, LT’s expanding role in transplant oncology now includes cases like CRC with liver metastases. However, due to the scarcity of donor organs, careful patient selection and ongoing evaluation of outcomes are critical [2,3].

This case report highlights the clinical outcomes of two CRC patients with multiple liver metastases who successfully underwent living donor liver transplantation (LDLT) in the year 2023. Both had complex medical histories and pre-transplant liver dysfunction, demonstrating the challenges and potential benefits of LT for advanced CRC. By examining these cases, we aim to underscore the feasibility and advantages of LDLT in complex CRC scenarios, inform pre- and post-transplant care strategies, and emphasize the importance of long-term follow-up. This report is a key reference for clinicians considering LT for CRC patients with liver metastases, offering practical insights to improve decision-making and patient care.

Case 1

Case details

A 56-year-old male was diagnosed with colon cancer with multiple liver metastases in 2007. Initial treatment consisted of palliative chemotherapy, which yielded a partial response, evidenced by a decrease in size and number of hepatic metastases on subsequent computed tomography scans. A near-complete response was observed on subsequent imaging, with no obvious metastatic lesions. This positive response prompted a surgical intervention in April 2008, including anterior resection of the primary sigmoid mass and radiofrequency ablation (RFA) of the remaining hepatic metastases. Post-operatively, the patient received adjuvant chemotherapy to reduce the risk of recurrence further.

Despite the initial positive response to treatment, the patient experienced disease progression. A magnetic resonance imaging (MRI) in July 2008 revealed the development of multiple small metastatic nodules in the right hepatic lobe. A follow-up MRI in July 2009 demonstrated stable RFA zones but no change in the size of metastatic lesions in other segments. This prompted multiple RFA sessions from March 2011 to September 2014. In 2014, lung metastases developed, requiring video-assisted thoracic surgery wedge resection. A subsequent mini-thoracotomy wedge resection was performed in 2015. In 2016, a S7 segmentectomy of the liver was undertaken. Palliative proton beam therapy (PBT) was delivered in 2017, 2018 and 2019, and a re-irradiation with PBT in 2023. The patient’s history included six sessions of RFA, one surgery related to cancer treatment, and radiation therapy, highlighting the extensive and challenging nature of his prior treatment regimen.

On May 30, 2023, the patient underwent a LDLT because of frequent tumor recurrence. Fig. 1 depicts the patient’s liver appearance.

Figure 1. The recipient 1’s metastasized liver. (A) Anterior surface. (B) Posterior surface.

Donor details

The spouse donated for a patient. The donor for patient 1 was a 55-year-old female with blood type AB-positive. She had a history of hypertension but no other reported illnesses. Her liver was deemed healthy and suitable for donation, with anticipating liver volume of 1,205 mL in preoperative imaging. The right lobe was chosen for transplantation, as shown in Fig. 2. The donor experienced no complications and was discharged after 7 days.

Figure 2. The liver of case 1’s donor. (A, B) Gross appearance of the right lobe of the donor’s liver.

Surgical details

The LT utilized a right lobe graft with expected graft volume 808 mL in preoperative image. The recipient underwent a 381-minute surgical procedure under anesthesia for a total of 448 minutes. The patient remained hospitalized for 29 days post-transplantation. No complications were reported during this period. The patient’s current status and long-term survival, crucial for evaluating the success of the transplant, should be discussed and monitored closely.

Case 2

Case details

A 49-year-old male was diagnosed with colon cancer that had metastasized to the liver in 2022. The initial treatment involved low anterior resection for rectal cancer, which was staged as pT3, N1b. Following surgery, the patient completed an entire course of chemotherapy (FOLFIRI+Avastin) to reduce the risk of cancer recurrence further. Due to the complications arising from liver metastasis, the patient was subjected to a LDLT on August 22, 2023. This procedure was aimed at replacing the compromised liver with a healthy one from a compatible LD, offering a potentially life-saving intervention for the patient. The metastasized illustration of the liver is shown in Fig. 3.

Figure 3. The recipient 2’s metastasized liver.

Donor details

The living liver donor is the patient’s friend. The donor for patient 2 was a 49-year-old male with blood type O-positive. He had no reported history of hypertension, diabetes, tuberculosis, or other diseases. His expected total liver volume of 1,482 mL according to preoperative liver images. The left lobe was chosen for transplantation, as illustrated in Fig. 4. The donor experienced no complications and was discharged after 8 days.

Figure 4. The liver of case 2’s donor. (A) The left lobe of the donor’s liver. (B) The LHV. LHV, left hepatic vein.

Surgery details

The LT utilized a left lobe graft from a LD with expected graft volume 542 mL in preoperative image. The recipient underwent a 304-minute surgical procedure under anesthesia for a total of 387 minutes. The patient remained hospitalized for 14 days post-transplantation. No complications were reported during this period. The patient’s status and long-term survival, crucial for evaluating the success of the transplant, should be discussed and monitored closely. The demographic details of patient 1 and 2 and their surgical details are given in Table 1.

Table 1 . Demographic and surgical details of case 1 and 2.

Detail	Case 1	Case 2
Patient detail
Diagnosis	CRLM	CRLM
Progress	Cirrhosis	Cirrhosis
Sex	Male	Male
Age (yr)	56	49
Height (cm)	173.0	172.0
Weight (kg)	82.6	62.0
BMI (kg/m2)	27.6	21.0
Donor detail
Sex	Female	Male
Age (yr)	55	49
Height (cm)	162.5	175.0
Weight (kg)	68.6	82.2
BMI (kg/m2)	26.0	26.8
Surgery detail
Whole liver (mL)	1,205	1,492
GRWR	0.94	1.53
Graft type	Rt. lobe	Lt. lobe
Warm ischemia time (sec)	370	350
Cold ischemia time (min)	97	50

CRLM, colorectal liver metastasis; BMI, body mass index; GRWR, graft-to-recipient weight ratio; Rt, right; Lt, left..

The management of colorectal liver metastasis (CRLM) is evolving, with LT emerging as a viable option for select patients. Advances in systemic therapies, surgical techniques, and tumor biology understanding drive this shift [1]. While surgical resection remains the gold standard for resectable CRLM, most patients present with unresectable disease and face poor outcomes with conventional treatments. The Oslo group pioneered LT for unresectable CRLM, demonstrating significant survival benefits compared to chemotherapy alone in carefully selected patients [3-5].

Meticulous patient selection is key for successful outcomes in LT for CRLM. Prognostic tools like the Oslo score and the Fong Clinical Risk score, along with tumor subtypes and response to therapy, guide decision-making in multidisciplinary settings [3-6]. However, organ availability remains a major challenge. Strategies like extended criteria donor livers, LDLT, and advanced machine perfusion technologies are being explored to expand the donor pool [7]. The role of technical resectability in LT selection is debated. Some studies suggest LT may be more beneficial even in technically resectable cases with high tumor burden, while others stress the importance of resectability. Understanding tumor biology is crucial, as CRLM is dynamic and risks occult disease. Advances in circulating tumor DNA analysis offer insights into disease progression and recurrence, aiding in better monitoring and treatment strategies [3,8].

Immunotherapy adds both challenges and opportunities. While immune checkpoint inhibitors (ICIs) show promise in CRLM treatment, their impact on transplant outcomes, particularly graft rejection, is still unclear. Research is ongoing to optimize timing, ICI type, and management strategies for CRLM patients undergoing LT. Establishing registries is essential for robust data collection, outcome assessment, and evidence-based guideline development [9,10].

In conclusion, LT for unresectable CRLM offers significant survival benefits and potential long-term disease control in selected patients. Continued research on refining patient selection criteria and expanding donor availability is critical for advancing the field. LDLT is especially promising for treating CRC with liver metastasis in unresectable or recurrent cases. However, stringent selection, comprehensive assessments, and careful post-transplant monitoring are crucial to maximizing success and minimizing risks. Further research is needed to establish clear guidelines for patient selection and treatment.

This research was supported by the Basic Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF-2023R1A2C2005946). However, Korean NRF did not influence study design, data analysis, data interpretation, or drafting of the manuscript.

Jongman Kim is a chief editor of the journal but was not involved in the review process of this manuscript. Any other authors have no conflict of interest.

Conceptualization: JK. Data curation: All. Formal analysis: AA, JK. Funding acquisition: JK. Investigation: JK. Methodology: AA, JK. Project administration: EL, YR, JK. Resources: JK. Software: SJ, NO, JK. Supervision: JK. Validation: JK. Visualization: AA, JK. Writing – original draft: AA. Writing – review & editing: JK.