Infections that cause cancer
Submitted by Dr.Kattlove’s Cancer Blog
Recently I learned my college roommate died of liver cancer. It was caused by an infection, in his case, the Hepatitis C virus. Several viruses can cause cancer, years after they first invaded us. That’s what happened to Mannie. After college, he also went to medical school and became an anesthesiologist. Sometime during the course of his career, he stuck himself with a needle that had been used on a patient with Hepatitis C and became infected with this virus.
The infection caused his liver to become inflamed and eventually scarred. After many years, cancer developed in his liver. This happens commonly with this infection. The only treatment is liver transplantation – that is removing his entire liver and replacing it with a new one from a person who has just died. Mannie had the transplant, but it didn’t help. The cancer came back in other places and he quickly succumbed.
Another liver cancer-causing virus is hepatitis B. This is actually a very common infection, particularly in Asia. It often causes liver cancer, one of the most common cancer-related causes of death in Asia. And, because many people in the last 20-30 years have been infected with either hepatitis B or C in the U.S., liver cancer is one of the few cancers that is increasing in frequency in the U.S. The viruses are typically spread by blood transfusions, sexual contact and shared needles by drug users. In 2008, nearly 20,000 people will die of liver cancer in the U.S.
Another common cancer-causing virus is HPV – Human Papilloma Virus. This virus often causes warts, but many forms of the virus cause cervical cancer. HPV can also cause other cancers, but cancer of the cervix is the most common.
But not only do virus infections cause cancer, a bacterial infection can also lead to cancer. The bacteria known as H. Pylori, is the major cause of stomach cancer. It also can cause lymphomas of the stomach, but these are less common.
But there is good news in all this. We can prevent many of these infections. A vaccine for Hepatitis B has been developed and is routinely given during childhood. This will eventually lead to the elimination of this virus and the liver cancer it causes. So far, sad to say, there is no vaccine for Hepatitis C. This virus is harder to produce in the laboratory.
Many have heard of the vaccine for HPV, perhaps because of its controversy. It will prevent about 70% of cancers of the cervix and is now recommended for young girls before they become sexually active (the virus is spread through sexual intercourse). This has become controversial as many worry that immunization condones early sexual activity. And, to tell the truth, cervical cancer isn’t a big problem in the U.S. Routine pap smears can find it before it becomes dangerous. But, world wide, cervical cancer is a big killer of women, so if the vaccine becomes available in developing countries where routine pap smears are rare, many lives will be saved.
And, now there is interest in getting rid of H. Pylori infections. The bug is easily killed with antibiotics. Doctors in countries where stomach cancer is a big problem, like Japan, are beginning to talk about screening everyone for this infection and giving them antibiotics.
So infections do cause cancer, but the future is bright as we are more able to prevent them, either with vaccines or antibiotics. That will be the easy part of cancer prevention. The heavy lifting will be in eliminating tobacco use and getting people to eat better and exercise more.
