Thirty Years of AIDS -- Cancer Trends in HIV, Then and Now
January 16, 2009
Until the mid-to-late 1970s, Kaposi's sarcoma (KS) was a rare form of cancer in high-income countries. When it did occur, it was mostly older men who were affected, with tumours appearing on their feet and legs. KS in these men caused mild disease. But in about 1979 that began to change. Doctors in Western Europe and the United States started to see the occasional young man who also developed KS. What made the new cases of KS particularly troubling was that tumours could appear almost anywhere on the body and spread aggressively. Over the next two years, dermatologists and cancer specialists noted that more and more young men were seeking care for this aggressive form of KS. These men often had swollen lymph nodes and some also had unexpected and unexplained weight loss, fever and fatigue.
Doctors in New York and San Francisco who monitored these men were deeply puzzled that some of their patients subsequently developed life-threatening complications with unusual infections -- pneumonia and brain infections caused by fungi and parasites, diarrhea and terrible skin, mouth and throat ulcers caused by out-of-control herpes viruses. These all suggested a significantly weakened immune system.
Sex and Germs
By 1981, doctors had found many cases of this strange new immune deficiency in the United States. In reviewing 41 such cases, New York dermatologist Dr. Alvin Friedman-Kein was astonished by the sudden appearance of fatal cancers associated with immune-deficient young men. He was able to check with cancer registries and found that until about 1979 no cases of KS in young men had been noted in New York City. What all his young patients had in common was that they had been highly sexually active with other men and many had repeated bouts of sexually transmitted infections, including gonorrhea, herpes viruses, hepatitis A or B, intestinal parasites and syphilis. Such high rates of sexual activity with many partners increased the risk that these men could have been exposed to a new sexually transmitted germ. Suspecting that these tumour-burdened, immune-suppressed men might be the harbinger of a new and terrible syndrome, Friedman-Kein wrote in 1981 that the 41 patients were probably "the tip of the iceberg." How right he was.
A few years later, the syndrome would be called AIDS and its cause -- a sexually transmitted virus that we now call HIV -- would be identified in 1983. But Friedman-Kein was correct in other ways as well. KS was merely the first of several cancers associated with HIV disease. In the early 1980s another cancer of the immune system, non-Hodgkin's lymphoma, was increasingly seen in people with AIDS. Along with KS, these two forms of cancer were initially so commonly associated with AIDS that they were called AIDS-defining cancers. And, so, as Friedman-Kein suspected, the giant iceberg of AIDS appeared and cases increased dramatically. Although AIDS cases in the late 1970s and early 1980s in North America were mostly male, the disease swiftly spread to women and children in a worldwide pandemic. As the population affected by AIDS broadened, invasive cervical cancer was added to the list of AIDS-defining cancers.
Death Takes a Holiday
In 1996, highly active antiretroviral therapy (HAART) was made available in high-income countries, and deaths from AIDS-related life-threatening infections and cancers began their steep decline. Such infections are now uncommon in people with HIV/AIDS who are engaged in their health care and treatment, at least in high-income countries. By suppressing HIV, HAART allows the immune system to begin repairing itself. However, HAART does not cure HIV infection and the repairs to the immune system are only partial. This means that HAART users have enough immunity to easily fight off AIDS-related infections, but they continue to have some degree of immune deficiency. Over the long term, this immune deficit may increase the risk of developing cancer.
In the 21st century a troubling trend appeared: Cancers unrelated to AIDS became more common in HIV positive people in North America and Western Europe. The range of cancers that were increasing varied from one country or region to another but generally included some of the following:
The reason(s) for an increase in these cancers is not clear but may be due to many factors. Here are some that we know about:
This is caused by exposure to the sexually transmitted humanpapilloma virus (HPV). Although HPV-related tumours are generally slow growing, enrolling in an HPV anal cancer/dysplasia screening program is a good way to keep track of any abnormal growths in the anus. Abnormal growths can be removed or killed before they become cancerous. Having protected anal intercourse helps prevent further exposure to HPV.
People who have had mono (mononucleosis) in the past are at increased risk for this cancer of the immune system. Hodgkin's disease appears to be triggered by infection with a herpes virus called EBV (Epstein Barr-Virus). So far, there is no simple test to predict who will get this virus but the appearance of any unusual signs/symptoms such as fever, unexpected weight loss and fatigue, night sweats and swollen lymph nodes should be investigated right away.
Although there are high rates of tobacco smoking among some people with HIV/AIDS, not everyone who is HIV positive and who gets lung cancer has smoked. Researchers are puzzled by this and suspect that there must be additional risk factors, but they have not found them so far.
This cancer is caused by exposure to hepatitis B and C viruses. Monitoring liver health and taking treatment for these infections can help keep this cancer from developing. Getting vaccinated for hepatitis B as well as engaging in safer sex and not sharing needles and other equipment for substance use will reduce the risk of acquiring hepatitis and many other germs.
In several upcoming CATIE News stories we will begin to explore trends in some of these cancers that are unrelated to AIDS.
This article was provided by Canadian AIDS Treatment Information Exchange. Visit CATIE's Web site to find out more about their activities, publications and services.
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