LIVER METASTASES

DEFINITION/INTRODUCTION

Liver metastases is malignancy of the hepatic cells following a  spreads from other malignant organs or tissues and this is more often than not due to  its size, increase rate of blood flow, double  perfusion by both the hepatic artery and portal vein. Also due to the Kupffer cell filtration ability combine to make it is much more common than primary liver cancers. This feature  of being a major site of metastatic growth is second only to lymph nodes in the body. Except for malignant tumors primarily in the brain any other cancer may spread to the liver but the most common source tumor that produce a liver metastases include the colon, breast, lung, pancreas as well as melanomas are very common. Less commonly cancers could spread are from the thyroid, prostate, and skin.

 The symptoms as at the time of presentation will reflect more of the primary cancer and metastases to the liver is usually discovered during investigations, though liver involvement may be shown by constitutional symptoms some of which are reduced appetite,fever, weight loss and sweating. patients with advanced hepatic involvement shows features suggestive of malignancy and hepatic enlargement. Others maybe abdominal pain and  jaundice. The risk factors mainly due to the size of the tumor, blood supply and position of the primary tumor furthermore spaces in the endothelial wall of liver blood vessels allow cancer cells to reach the functional hepatic cells.

  INVESTIGATIONS

Some form of clinical assessment will give a clue of liver involvement before the major investigation and every patient with any form of primary malignancy should be fully screened for metastases to various sites including the liver,except for brain tumors that are not expected to metastasis to the liver,common investigation showing a raised level of alkaline phosphatase or a mass apparent on ultrasound, CT, or MRI examination of the liver may provide a presumptive diagnosis,more reliable diagnosis is got from biopsy taken under ultrasound,CT guided or during laparoscopic procedure. Commonly, multiple nodular metastases are found that often cause striking hepatomegaly and may replace over 80% of existent hepatic parenchyma.in some cases the primary tumor may give a rise to some enzymes in the liver for example carcinoembyronic antigen is released by the primary tumor into the serum in about 70% of patients with colorectal cancer, there is usually a fall in serum levels after primary tumor removal.other investigations include PET scan,liver function test,full blood count,serum bilurbin.

MANAGEMENT

 Management of metastatic liver malignancy is multi-factorial based, including the primary site of the tumor , the percentage of tumor in the liver parenchyma , the presence of other site of metastasis (such as, to the spleen), and any other coexisting health condition. A combination of all the above factors are of huge  importance when the management plans is considered .

 Surgical: Surgical management with the goal of curing the malignancy is an option in some type of tumors. If the site of metastasis is the part of the liver without any form metastasis to any other organ in the body then technically a cure can be achieved when the part of the liver containing the metastatic cells is removed. On  a general note , patients  who  had the whole tumor removed have the best chance of surviving. In most cases when surgery is the treatment plan, it is done in with chemotherapy as an adjunct. Examples of lesions where surgical treatment could be considered include: large intestine and rectum, anus, neuroendocrine, breast and lungs . Surgical options include: Partial liver resection (the portion of the liver with metastatic cells is removed) or hemi-hepatectomy (one half of the liver is resected).

Microwave ablation: In this treatment modality heat therapy is applied to destroy the metastatic cells. The treatment is done under ultrasound guidance with a special probe inserted. The probe then “heats up” the tumor to kill it. Not all tumors responds to this treatment and sometimes, microwave might be used in combination with liver resection.  Radiofrequency ablation is  a heat therapy, with some  similarity to microwave.

 Chemotherapy :Patients with metastatic malignancy of the liver can have their lives prolonged by chemotherapy especially in patients that cannot with stand surgery, although chemotherapy may not be curative cure on its own. Chemotherapy is a treatment  option that uses anti-neoplastic medications to destroy malignant cells, or to stop their multiplication. though it is not likely to bring about a cure, but may reduce size of  the tumor down to slow the growth rate of the malignancy. Chemotherapy is more efficient when used in combination with other treatment modalities for example:Surgical. Chemotherapy is mainly given systemically through the vein of either the arm or, more oftenly, through a specially-implanted port in the chest. Metastatic pancreatic tumor to the liver is an example of cancer that would be typically managed with systemic chemotherapy. Another means of administering chemotherapeutic agents is Chemoembolisation. In  this treatment modality, medications utilized in chemotherapy is given directly into branches of the hepatic vessel  which  supply  the tumor and it is combined with a substance that blocks the  blood vessel and obstruct the blood supply and to starve the tumor of nourishment. This form of treatment might be utilized in cases of  neuroendocrine or renal malignancies . Not all metastatic cancers are responsive to this type of treatment. Furthermore hepatic arterial infusion is  another management plan with some similarities with chemoembolisation but no special substance is given  to deprive the cells of  blood supply and a commonly used drug is  floxuridine(FUDR).

Radiation therapy: This is a treatment which utilizes high energy beams of radiation which are focused on cancerous tissue. This kills cancer cells, or stops cancer cells from multiplying. This is currently not a commonly used treatment option for metastatic liver malignancy, and not all malignant cell types or tumors are amenable to this treatment option.

Radioembolisation:This is a newer form of treatment where radiation is attached to small beads  called microspheres which are then injected into the blood vessels supplying the liver malignancy.

Stereotactic body radiation therapy:this is a type of external beam that deliver high dose of radiation directly to a tumor when there are 1-3 small liver metastases .It avoids radiation to normal tissues.

Liver transplant

This normally available to only a small number of patients with liver metastasis are candidates for a liver transplant because of the strict criteria they have to meet.

COMPLICATIONS

Complications are mainly due to tumor occupying a large proportion of the liver .they include:

Obstruction of bile flow

Reduced appetite

Liver failure

Pains

Weight loss

CAN YOU LIVE WITH LIVER CANCER?

 Liver cancer is a chronic disease that is debilitating  and requires long term management especially with the high rate of reoccurrence making it is a difficult condition to live with.

SURVIVAL RATE

Survival rates are estimates, the outcome varies depending on  various  factors peculiar

to each patient.

Localized tumors: In this stage the cancer is still restricted to the hepatic parenchyma, and this includes stages I, II, and some stage III cancers. This includes different type of liver cancers, some might be  easier to manage than others. The 5-year survival rate for people with localized liver cancer is around 30.5%.though some patients may survive longer than that.

 Regional  liver cancers :This means the cancer has spread into nearby organs like the spleen or has spread to nearby lymph nodes, and includes stages IIIC and IVA cancers. For regional stage liver cancer, the 5-year survival rate is about 10.7%.

Distant metastatic liver: This means that the cancer has spread to distant organs or tissues and is this is equivalent to stage IVB. The 5-year relative survival rate for distant stage liver cancer is about 3.1%.

In general, survival rates are higher for people who can have surgery to remove their cancer,

regardless of the stage. For example, studies have shown that patients with small, resectable

tumors who do not have cirrhosis or other serious health problems are likely to do well if their

cancers are removed. Their overall 5-year survival is over 50%. For people with early-stage liver

cancers who have a liver transplant, the 5-year survival rate is in the range of 60% to 70%.

PREVENTION

Prevention of liver cancer can be mainly be by lifestyle modifications which will minimize risk factors for cancer.

Reduce consumption of alcohol

Prevent risk factors for hepatitis B and C e.g sharing sharps

Early management of other cancers to prevent metastases to the liver

Vaccination against hepatitis B

Avoid unprotected sex

Avoid exposure to arsenic  

Transfusion of only properly screened blood.

Limiting liver metabolized drugs

Eating healthy diet rich in fresh vegetable and grains

PROGNOSIS

Prognosis is generally very poor but with better chances  in patients with surgically amenable tumors and without spread to other organs and tissues.