Introduction
Liver cancer is a devastating disease. The liver is the main metabolic organ in the body, involved in the carbohydrate, fat and protein metabolism.
The liver is one of the major detoxification organs, it is responsible to produce clotting factors, manufactures half of all cholesterol in the body and has important functions regarding the immune recognition and the mounting of inflammatory responses in the body. When liver cells turn cancerous these cell functions are missing and when the majority of cells are affected, the metabolism and the other functions just mentioned derail. The result is a decompensation and worsening of the patient’s condition in addition to the effect of the cancer. In the last few decades a solution has been developed for this problem: liver transplantation.
The liver happens to be one of the organs in the body that has very few surface antigens on its cells and this makes liver transplants easier than for transplants of other organs.
The first transplant was done in 1963 and thousands of liver transplants have been done since then. It took some time before this surgical procedure became relatively safe in the hands of the transplantation surgeon.
Only specialized transplantation teams offer this service and there is a rigid routine of repeat ongoing testing that has to be followed after the procedure. However, as we shall see later the 5-year survival data speaks for itself and transplantation is now done at a much earlier stage of liver cancer to improve the outcome of this otherwise dismal disease.
Some carcinogens that cause liver cancer
| nitrosamines (from nitrate and nitrite treated foods) | DDT, heptachlor, aldrin and other pesticides |
| chloroform | vinyl chloride |
| dioxane (solvent) | diallate (herbicide) |
| hydrazine (rocket fuel) | trichloroethylene (solvent used with dry-cleaning) |
| aminoazobenzene (industrial dye) | anabolic steroids |
| aflatoxins (moldy peanuts) | luteoskyrin and others (rice toxins) |
| sassafras oil | tannic acid, tannins (leather industry) |
| carbon tetrachloride | griseofulvin |
| cigarette smoking | thorotrast (old X-ray dye) |
| hepatitis B and C | alcohol (dose dependent) |
The table above lists some of the chemicals that are known to cause liver cancer in man. The food born causes can be eliminated by watching expiry dates on food packages and proper refrigeration. However, environmental pollutants such as vinyl chloride, chloroform, herbicides, rocket fuel and insecticides need intervention from governments to achieve a safe environment.
This is a problem as it often interferes with direct interests of industry. However, much has already been achieved. Just to give an example: decades ago it became known that aflatoxins are highly toxic to the liver and produce liver cancer. The aflatoxins are produced in the mold found from improper storage of peanuts in farms. These toxic substances ended up in peanut butter, which was eaten by everyone. Through new legislation strict storage and manufacturer guidelines were introduced, which resulted in a significant drop of the liver cancer rate in the US. Nobody in the US is now exposed to aflatoxin contaminated peanut butter. However, there are many places elsewhere in the world, where even today moldy food is a major source of liver cancer!
References:
1. Cancer: Principles &Practice of Oncology.4th edition. Edited by Vincent T. DeVita, Jr. et al. Lippincott, Philadelphia,PA, 1993. Chapter on Hepatobiliary Neoplasms.
2. Cancer: Principles&Practice of Oncology. 5th edition, volume 1. Edited by Vincent T. DeVita, Jr. et al. Lippincott-Raven Publ., Philadelphia,PA, 1997. Chapter on Hepatobiliary Neoplasms.
3. SA Hussain et al. Ann Oncol 2001 Feb;12(2):161-172.
4. M Nakamura et al. J Cell Physiol 2001 Jun;187(3):392-401.
