This protocol describes the laparoscopic resection of colorectal cancer liver metastases combined with ultrasound-guided microwave ablation. This technique can safely, effectively, and accurately treat refractory liver metastases <3 cm, reduce postoperative complications, and accelerate the postoperative rehabilitation of patients.
Laparoscopic hepatectomy is a common treatment for colorectal cancer liver metastasis. Previously, a sufficient number of functional liver masses had to be maintained during laparoscopic hepatectomy, with a residual liver volume of >40% in cirrhotic patients and >30% in non-cirrhotic patients. The high incidence of complications such as bleeding, bile leakage, or liver failure due to the exposure and difficulty of the resection of specific liver segments such as S2 and S7 reduces the success rate of liver resection. At present, microwave ablation is mainly applied in the treatment of liver metastasis using a percutaneous approach, which makes it difficult to identify hidden parts or small lesions. For some liver segments, the percutaneous puncture of liver segment 7 (S7) is likely to pass through the thoracic cavity, and the percutaneous puncture of liver segment 2 (S2) adjacent to the diaphragm is likely to injure the diaphragm and heart; these issues restrict the application of percutaneous ablation in colorectal cancer liver metastasis. Considering multiple lesions, laparoscopic microwave ablation combined with hepatectomy was performed in this study. The location of the lesions was determined by contrast-enhanced ultrasound under laparoscopy, and small lesions that were difficult to detect before the operation were identified. For the scattered lesions, which had diameters less than 3 cm and were difficult to resect, ablation was adopted to substitute hepatectomy. This technique helped to more explicitly locate the tumors, simplified the operation procedures, reduced the risk of complications such as bleeding and bile leakage, shortened the operation time, accelerated the postoperative recovery, significantly improved the success rate of operation, and enhanced the clinical prognosis of colorectal cancer liver metastasis by surgical resection.
Colorectal cancer is the third most common cause of cancer-related death worldwide1, and the most common site of hematogenous metastases from colorectal cancer is the liver; this metastasis occurs in up to 50% of colorectal patients and is the leading cause of death in colorectal cancer patients2. For colorectal cancer patients without liver metastases, survival can be prolonged by surgical resection and postoperative adjuvant chemotherapy, and interventional techniques. In the case of resectable liver metastases, those with a diameter of less than 3 cm can be treated by surgical local excision, radiological intervention, cryotherapy, radiofrequency ablation, and microwave ablation to improve the survival rate of patients3. For unresectable colorectal cancer liver metastases, conventional chemotherapy, interventional therapy, and other treatment strategies have limited survival benefits for the vast majority of patients.
Surgery is the gold standard for liver metastases from colorectal cancer, with a 5 year survival rate of 40%. Only 20%-30% of patients with colorectal liver metastases can benefit from surgical treatment, and most patients with unresectable colorectal liver metastases experience limited benefit from traditional conservative treatment4. An important method in the treatment of colorectal cancer liver metastases is thermal ablation, including microwave ablation and radiofrequency ablation; these two techniques induce cell death through coagulation necrosis caused by local hyperthermia. The main indications of thermal ablation include (i) unresectable liver lesions; (ii) combination with hepatectomy; (iii) patients with severe comorbidities or poor performance status (PS); (iv) small (<3 cm) solitary lesions otherwise requiring segmentectomy; and (v) patient preference5. Among them, microwave ablation (MWA) is a safe and effective treatment that can prolong the survival of patients. It has a wide range of active heating areas and does not depend on electrical conduction in the tumor tissue. This energy transfer is not limited by tissue scorching. Compared with radiofrequency ablation, microwave ablation has a higher temperature in the tumor tissue, shorter treatment time, and larger treatment range6.
Multiple intrahepatic metastases often occur in colorectal cancer liver metastases. In conventional treatment, chemotherapy, immunotherapy, interventional therapy, microwave therapy, radiofrequency ablation, and other methods can improve the survival rate of patients. The 5 year survival rate is 50%, but the survival rate is still low7. Surgical resection is still an important method for the treatment of liver metastases. Due to multiple liver metastases, small residual liver volume, postoperative bleeding, bile leakage, and inflow or outflow tract obstruction, which lead to the risk of liver failure, the surgical resection of multiple liver metastases is difficult. Three-quarters of patients are diagnosed with unresectable liver metastases8. Laparoscopic hepatectomy combined with microwave ablation in the treatment of colorectal cancer liver metastases can avoid the small amount of residual liver limiting the operation, reduce the adverse reactions of systemic chemotherapy, and overcome the electrical conduction barrier of radiofrequency ablation, thereby improving the success rate of surgery, prolonging the survival time of patients, and achieving a better prognosis of colorectal cancer liver metastases3,9.
This protocol describes the precision treatment of laparoscopic hepatectomy combined with microwave ablation for tumors <3 cm, occult liver metastases, and multiple liver metastases with positioning using laparoscopic ultrasound.
This study was approved by the Ethics Committee of the Sixth Affiliated Hospital, Sun Yat-sen University. The diagnostic criteria and treatment strategies refer to Chinese guidelines for the diagnosis and comprehensive treatment of colorectal liver metastases (version 2018) and the Shanghai International Consensus on Diagnosis and Comprehensive Treatment of Colorectal Liver Metastases (Version 2019). The patient had clinical symptoms such as hematochezia, intestinal obstruction, liver pain, and weight loss. Patients with unresectable multiple liver metastases diagnosed by CT, MR, B-ultrasound, liver function, CEA, AFP, and other tumor markers were included in the study. The representative patient and their family have been informed of the contents of this agreement, the video shooting, and other relevant content; a signed informed consent form and authorization have been obtained from the patient.
1. Instruments for operation
2. Preparation for operation
3. Laparoscopic hepatectomy combined with intraoperative microwave ablation for colorectal cancer liver metastases
4. Postoperative care
For patients with liver metastases from past colorectal cancer, patients with unilateral liver metastases, or patients with few liver metastases can undergo surgical resection and obtain a good prognosis. Nevertheless, in patients with unresectable colorectal cancer with multiple liver metastases in both lobes, conservative treatment has a poor prognosis and a low 5 year survival rate. However, hepatectomy combined with microwave ablation can further improve the survival rate of patients and achieve a good prognosis compared with single or unilateral liver metastases from colorectal cancer after surgical resection. With patients with a similar prognosis, Tanaka et al. compared 16 patients with colorectal cancer liver multiple metastases who underwent hepatectomy and microwave ablation with 37 patients with colorectal cancer unilateral or isolated liver metastases who underwent hepatectomy, microwave ablation, and surgical resection. The study results showed that liver resection combined with microwave ablation for unresectable colorectal cancer liver metastases could prolong the survival of patients10.
The surgical technique was successful in this case. The operation time was 130 min. During the operation, the microwave ablation of liver metastases was successful under a power of 55 W for 5 min. The intraoperative blood loss was low at about 50 mL. The patient had no postoperative complications such as biliary leakage and liver failure and was discharged 8 days after surgery using the ERAS rehabilitation philosophy (Table 1).
Figure 1: Intraoperative placement of the trocars. A 10 cm trocar was inserted into the navel, and the abdominal cavity was aerated. The abdominal pressure was maintained at 12-15 mmHg. Trocars of 12 cm were placed under the xiphoid process, and three more 5 cm trocars were placed on the left and right sides. Please click here to view a larger version of this figure.
Figure 2: Laparoscopic abdominal exploration. (A) Exploration of the abdominal cavity and liver surface. (B) Dissection of the round ligament and falciform ligament. Please click here to view a larger version of this figure.
Figure 3: Determination of the location of colorectal cancer liver metastases. (A) Contrast-enhanced ultrasound. (B) Laparoscopic ultrasound whole liver scan. Please click here to view a larger version of this figure.
Figure 4: Anatomical lobectomy or segmental resection. (A) Determination of the parenchymal resection line. (B) Dissection of the umbilical fissure vein. (C) The pedicles of segment II and segment III of the liver were exposed. (D) The section II and section III hepatic pedicles were cut off. Please click here to view a larger version of this figure.
Figure 5: Laparoscopic ultrasound localization of colorectal cancer liver metastases and local resection. (A) Ultrasound localization of metastases in the S8 segment of the liver. (B) The distance between the resection margin and the tumor was more than 1 cm, and local resection of the S8 segment of the liver was performed. Please click here to view a larger version of this figure.
Figure 6: Ultrasound-guided microwave ablation of metastases in the S5 segment of the liver. (A) Ultrasound localization of metastases in the S5 segment of the liver and the extent of their ablation. (B) If the puncture path avoids the thoracic cavity and surrounding organs, direct ultrasound-guided ablation of liver S5 segment metastases can be performed. Please click here to view a larger version of this figure.
Figure 7: Dissociation of the right perihepatic ligament was dissociated and ultrasound-guided microwave ablation of the metastases in the S7 segment of the liver. (A) Separating the right perihepatic ligament. (B) Descending rotation of the liver. (C) Ultrasound localization of liver metastases in the S7 segment. (D) Ultrasound-guided microwave ablation of metastases in the S7 segment of the liver. Please click here to view a larger version of this figure.
Figure 8: Intraoperative hemostasis and placement of the drainage tubes. (A) Hemostasis of the liver parenchyma wound. (B) Placement of a drainage tube under the liver section. Please click here to view a larger version of this figure.
Operational parameters | Values |
Operation time | 130 min |
Microwave ablation time | 5 min |
Blood loss | 50 mL |
Duration of stay | 1 week |
Table 1: Results for the case study presented here.
The main metastatic site of colorectal cancer metastasis is the liver. Liver resection is the treatment for colorectal cancer liver metastases, and liver resection can improve the survival rate of patients11. As colorectal cancer metastasizes to the liver through the blood, resulting in multiple liver metastases in both lobes, and the remaining liver volume is small, about 75% of liver metastases in colorectal cancer patients cannot be surgically removed12. Systemic chemotherapy, interventional therapy, and immunotherapy can improve the survival rate of patients with liver metastases from colorectal cancer, but they are prone to adverse reactions such as nausea and vomiting, alopecia, bone marrow suppression, and even tumor recurrence in a short period of time. Radiofrequency ablation and microwave ablation have good controllability, high repeatability, fewer complications, and prolonged survival of patients with liver metastases.5 Gavriilidis et al. retrospectively analyzed radiofrequency ablation and microwave ablation in the treatment of colorectal cancer liver metastases smaller than 3 cm and showed that there was no significant difference in the treatment effects between the two13. Over the past decade, thermal ablation techniques (radiofrequency or microwave ablation) have been increasingly used to improve patient survival while expanding the number of potentially curative patients14.
Compared with radiofrequency ablation (RFA), although the therapeutic effect of microwave ablation in the treatment of colorectal cancer liver metastases is similar, microwave ablation (MWA) has more advantages, including a wide ablation range, short ablation time, high thermal efficiency, good ablation sensitivity, and reduced heat dissipation, which avoids skin burns15. Microwave ablation is a recognized multimodal treatment technique for hepatocellular carcinoma and colorectal cancer liver metastases. Abreu de Carvalho et al. analyzed laparoscopic microwave ablation (MWA) in 17 cases of colorectal cancer liver metastases (CRLM) and 30 cases of hepatocellular carcinoma (HCC). Compared to percutaneous microwave liver ablation (MWA), laparoscopic microwave ablation (MWA) for colorectal cancer liver metastases (CRLM) had higher local recurrence (LR) of hepatocellular carcinoma (HCC) and lower local recurrence of colorectal cancer liver metastases (CRLM)16. It was shown that laparoscopic microwave ablation (MWA) in the treatment of colorectal cancer liver metastases (CRLM) could reduce the recurrence rate of colorectal cancer liver metastases. In addition, microwave ablation is currently used for percutaneous liver puncture for liver metastases. For some occult liver metastases with a diameter of less than 3 cm, microwave ablation can achieve a good therapeutic effect. Due to the occult location of liver metastases, percutaneous liver puncture is limited and prone to damaging important tissues and organs adjacent to the liver. For example, an external puncture of the S7 segment can easily pass through the chest cavity, and an external puncture of the S2 segment is close to the diaphragm and prone to damaging the diaphragm and/or the heart3,14. These blind areas limit the application of percutaneous ablation in colorectal liver metastases.
Laparoscopic hepatectomy for colorectal liver metastases is a routine treatment, and the surgical resection of liver metastases is the only chance for long-term survival17. Laparoscopic hepatectomy requires the removal of tumors with negative histological margins while preserving adequate liver parenchyma. For liver metastases in certain locations, the liver resection is difficult to expose, and postoperative complications such as bleeding, bile leakage, infection, and liver failure are likely to occur. Colorectal cancer liver metastases are often multi-lobular metastases, meaning simple liver resection is difficult. In the past, neoadjuvant chemotherapy was feasible before liver resection to make liver metastases smaller. After evaluation, the residual liver volume was enough to maintain the daily life needs of the body, and laparoscopic hepatectomy was feasible. However, the tumor recurred rapidly after the operation because of some scattered and hidden small metastases that could not be resected. Therefore, laparoscopic hepatectomy combined with systemic chemotherapy, interventional therapy, microwave ablation, and radiofrequency ablation is generally required. Laparoscopic liver resection combined with ultrasound localization microwave ablation can better treat colorectal cancer liver metastases and can avoid the systemic adverse reactions of chemotherapy, interventional bleeding, liver function damage, and the poor heat conduction of radiofrequency ablation11,18,19. Wada et al.20 divided 82 patients with colorectal cancer liver metastases into a Y group and an N group. In group Y, 16 cases received microwave ablation (MWA), 9 cases received hepatectomy combined with microwave ablation, and 4 cases received simple hepatectomy. In group N, 28 patients underwent percutaneous microwave ablation, and 25 patients underwent liver resection combined with microwave ablation. The results showed that the survival rates of group Y and group N were similar, and the survival rate of patients with unresectable colorectal cancer liver metastases who underwent hepatectomy combined with microwave ablation was similar to that of patients with resectable colorectal cancer liver metastases. Hepatectomy combined with microwave ablation can prolong the survival of patients with unresectable colorectal liver metastases20. In laparoscopic liver resection combined with ultrasound-positioning microwave ablation technology, laparoscopic ultrasound can accurately locate small liver metastases and avoid damage to important tissues and organs around the liver, such as the diaphragm and myocardium. Due to its heat conduction, microwave therapy can better treat liver metastases with a tumor diameter of less than 3 cm. For tiny metastases that are hidden and difficult to expose, microwave ablation can also be used under the guidance of laparoscopic ultrasound positioning to accurately treat liver metastases and benefit patients21.
Laparoscopic hepatectomy combined with laparoscopic ultrasonic localization microwave ablation has brought benefits in treating the liver metastasis of colorectal cancer, but it also has some shortcomings. The thermal ablation conduction range of laparoscopic hepatectomy combined with laparoscopic ultrasonic localization microwave ablation is small, and the treatment effect for metastases larger than 3 cm is not good. In the ablation process, it is difficult to control the ablation degree of the tumor margins, and the tumor ablation is incomplete. If the metastatic tumor recurs after surgery, microwave ablation or hepatic artery chemoembolization should be performed again. The heat transfer range of microwave ablation instruments should be further improved. For metastases located near large blood vessels, the “heat dissipation effect” of passive heating from the radiofrequency ablation is limited due to the cooling effect of blood flow. The active heating effect of microwave ablation can effectively avoid this drawback of radiofrequency ablation, but there is a risk of damage to large vessels adjacent to the metastases. Therefore, it is necessary to locate the large vessels and the position of the microwave ablation needle under the laparoscopic ultrasound probe. Since the effective range of microwave ablation is 3 cm, the distance between the microwave ablation needle and the large vessel should be less than 1.5 cm. If there are irregular metastases near large vessels, multiple microwave ablation can be performed under laparoscopic ultrasound localization. This can prolong the treatment time of microwave ablation, further improve the heat conduction induction system of microwave ablation, and improve the efficiency of microwave ablation.
We have mainly described the application of laparoscopic hepatectomy combined with ultrasonic localization and microwave ablation in the treatment of colorectal cancer liver metastases, but our unit has only recently carried out this treatment mode, and the number of patients collected is still relatively small. This technique has been introduced in this paper, and more patient cases will be provided for statistical analysis in the future to further demonstrate the benefits of laparoscopic hepatectomy combined with microwave ablation in the treatment of colorectal cancer liver metastases in patients.
Laparoscopic liver resection combined with ultrasound positioning microwave ablation for difficult liver resection can shorten the method time, reduce the risk of bleeding, bile leakage, and other risks, speed up the postoperative recovery, and also improve the success rate of surgery and prolong the survival of patients.
The authors have nothing to disclose.
This work does not have any funding sources.
0.9% sodium chloride solution | Foshan Shuanghe Commercial Co., Ltd | H20013095 | Dilute antibiotics, irrigate. |
2-0 polyglactin 910 sutures | Johnson & Johnson Medical Devices | W8400 | Close the Trocar hole. |
3 D laparoscopic | STORZ | 26605BA | Surgical treatment under direct vision, minimally invasive |
Absorbable Hemostat | ETHICON | 1962 | wound hemostasis |
BiClamp E Lap | ERBE Elektromedizin GmbH | 20195-136 | Intraoperative wound hemostasis |
Cefoperazone Sulbactam Sodium | Pfizer Pharmaceuticals Ltd | H20020597 | infection prevention |
Laparoscopic ultrasound probe | HITACHI | ALOKA-UST5418 | Intraoperative localization of liver metastases |
LIGACLIP Multiple Clip Applier and Ligating Clips | Ethicon Endo – Surgery, LLC | ER320 | Clamp tiny blood vessels and bile ducts |
Microwave ablation System | Nanjing Yigao Microwave System Engineering Co., Ltd, China | ECO-100A110 | Microwave ablation of liver metastases |
Polymer ligation clips | Teleflex Medical, USA | Hem-lock544233 | Clipping of broken ends of blood vessels and bile ducts |
Silica gel drainage tube | BAINUS MEDICAL | YY-Fr16 | Drainage of peritoneal fluid |
Ultrasonic knife | Johnson & Johnson Medical Devices | HAR36 | Tissue cutting, microvascular hemostasis |