Most of the tumors that involve the liver are liver metastases, that is, they are secondary locations of a tumor originating in another organ, which are produced by blood dissemination.
Tumors that produce liver metastases are, in order of frequency, the following:
- bronchogenic carcinoma
- prostatic carcinoma
- Colorectal cancer
- mammary carcinoma
- pancreatic cancer
- stomach cancer
- Kidney cancer
- uterine cancer
About 40% of patients who die from solid organ cancer have liver metastases.
Of these, the primary tumor that most frequently undergoes hepatic treatment is that of colorectal origin: more than 50% of patients who have had colorectal cancer subsequently receive treatment for hepatic secondary cancer. Of these, 15-25% of patients present liver metastases at the time of diagnosis (synchronous metastases), while the remainder develop them later in variable periods of time (metachronous metastases). In the case of synchronous liver metastases, only 10-20% of these patients present a disease that is potentially treatable with surgery (resectable).
Diagnosis
The vast majority of patients do not present symptoms until they reach an advanced stage of the disease. When they do occur, the most common are:
- vague, nonspecific abdominal pain
- jaundice: yellowing of the skin, mucous membranes and eyes
- palpable abdominal mass on the right side, only identifiable when large
- ascites: accumulation of serous fluid in the abdomen, which occurs when there is increased pressure in the portal venous system
- weight loss and anorexia
- fever
- vague gastrointestinal discomfort, caused by compression of the tumor on the stomach and intestine
Based on these manifestations alone, the diagnosis of early liver metastasis is unlikely. Many resectable lesions can be diagnosed earlier, even in the absence of symptoms, through complementary tests performed for another cause (incidental diagnosis).
Colorectal metastases: treatment
Treatment modalities for liver metastases are varied and multiple: their choice depends on the intrinsic characteristics of the disease and the clinical conditions of the patient. Treatment modalities should be used to increase the possibility of resection of the lesion, and not to replace another, since today surgical treatment is the best possible option. The natural history of each patient with liver metastases is highly variable.
Regarding liver metastases from colorectal cancer, in the absence of treatment 60-70% of these patients die within one year, and 100% within 3 years. Resection of a single metastatic lesion secondary to colorectal cancer may have a 5-year survival of greater than 60%.
When a synchronous liver metastasis is identified during a resection of colorectal cancer, it can be resected immediately (combined surgical resection) or in a second surgical stage (delayed liver resection), depending on colon preparation, the importance of the surgical procedure the primary disease, the expected extent of liver resection, the general conditions of the patient, and the experience of the surgical team.
In general, contraindications to major liver resection for the treatment of metastatic disease include global involvement of the liver, advanced cirrhosis, jaundice (except in the case of extrinsic bile duct obstruction), vena cava or portal vein invasion and involvement of extrahepatic organs.
Metastatic liver disease is generally a contraindication for liver transplantation, except for cases of selected tumors, such as carcinoid tumor.
Survival after resection of liver metastases from colorectal cancer depends on multiple factors, including the size and number of metastases and the presence of residual localized disease after the intervention.
A wide variety of other treatments have been proposed for the management of liver metastatic disease from colorectal cancer. Chemotherapy with 5-fluorouracil and platinum compounds seems to give some results, although only 20% of patients truly benefit from systemic intravenous administration of chemotherapeutics. Pump infusion directly into the hepatic artery (infusaid) is performed at various centers and appears to be more effective, with comparably lower toxicity rates. Locoregional adjuvant chemotherapy after resection has limited effect.
Colorectal metastases: follow-up
Given the frequency in which colon cancer produces liver metastases, strict follow-up is indicated in these patients, with regular laboratory tests to identify possible liver involvement as early as possible. This includes the following:
- CEA and CEA 19-9: these are tumor markers that, when elevated, are highly specific for the presence of liver metastases (on the other hand, they are not very specific for the diagnosis of the primary tumor). Despite this, they are not sufficient for the diagnosis of disease, since they can be elevated due to other causes such as alcoholic cirrhosis, intestinal polyps, pancreatitis, inflammatory bowel disease, and diabetes mellitus. In these cases, tumor markers are moderately elevated. A markedly elevated value may indicate disease recurrence or tumor persistence, but not tumor location. Conversely, markers may not be elevated even in the presence of liver metastases.
- Liver enzymes (AST, ALT, GGT), are not very specific but indicate compromised liver function
- Ultrasound of the upper abdomen
- Contrast-enhanced CT of the abdomen, generally considered the best imaging method due to its availability and accuracy
- MRI (magnetic resonance imaging) of the abdomen, also very useful for the possibility of performing a cholangiorhaphy
- PET-18-FDG ( fluorodeoxyglucoside ): a labeled glycoside is injected that is mainly taken up by tumor cells, which have a more active metabolism. It is a useful study for evaluating the response to chemotherapy, radiotherapy, and chemoembolization of liver metastases.
Normal values, associated with negative imaging studies, allow us to exclude the presence of metastases with a sensitivity of approximately 95%.
Resections of non-colorectal metastases
Neuroendocrine neoplasms, including metastatic carcinoids, represent the second most frequent indication for resection of hepatic secondary disease, mainly for palliative purposes, after failure of pharmacological therapy for the syndrome, as well as the use of octreotide or chemotherapy. Hepatic metastases from neoplasms other than colorectal cancer and neuroendocrine neoplasms (primaries of the lung, breast, stomach, pancreas, melanoma, and the rest of the gastrointestinal tract) are characterized by a worse prognosis. Long-term survival after liver resection for a primary tumor of the pancreas and melanoma has not been reported, except for those performed for single lesions and at a considerable distance from the resection of the primary tumor.