Cancer comes from the uncontrolled growth of abnormal cells in the body. These cells do not respond to regular cell signals that would normally tell them not to grow, replicate, or move to different areas of the body. Sometimes, these cells can join together and form a solid mass, or tumor, in a particular area of the body. An example of this would be abnormal cell growth in the liver that leads to a liver tumor (liver cancer). In other cases, these cells can replicate and travel throughout the bloodstream, causing a blood cancer like leukemia.
Cancer can be caused by a variety of things. Cells can become abnormal after being exposed to damage or toxins, such as radiation or cigarette smoke. Cells may also become abnormal due to mutations in their genes or older age. The type of cancer an individual has depends on the type of cells that originally became abnormal and where they are located. The severity of a cancer is often based on how fast it has spread or other characteristics of the abnormal cells.
How is cancer related to HIV?
There are several factors that may contribute to the relationship between HIV and cancer. First, general immune suppression may increase an individual’s risk of getting cancer. HIV infects human T cells (CD4 cells), which are important in the immune system response. These cells help keep us from getting sick from infections and cancers. If T cell numbers decrease as a result of HIV (or untreated HIV), the normal monitoring function of the immune system can be impaired. This allows cancers to develop and grow.1
Additionally, being immunosuppressed (having a weakened immune system) allows individuals with HIV to be more susceptible to viruses, including cancer-causing viruses. Viral infections including human herpes virus 8 (HHV-8), human papillomavirus (HPV), Epstein-Barr virus, hepatitis C virus, and more, can lead to (or increase the risk of) various cancers. For example, if an individual with HIV has a weakened immune system, they are more likely to get HHV-8, which can then become severe and progress to a cancer called Kaposi sarcoma. Positively, rates of developing these immunosuppression-related cancers are declining with the regular use of antiretroviral therapy (ART), which helps suppress HIV and keeps the immune system stronger for longer.1,2
Additionally, there are other theories that suggest that HIV itself or its treatment may interact with normal cell functioning and may increase a person’s risk of developing certain cancers or make an individual more susceptible to cancer-causing damage like tobacco smoke, however, more information is needed on these topics.1
Specific cancers related to HIV
Cancers related to HIV can be divided into two categories. AIDS-defining cancers and non-AIDS-defining cancers. If an individual is diagnosed with an AIDS-defining cancer, they are considered to have AIDS (Acquired immunodeficiency syndrome), the most advanced stage of HIV. These conditions can occur regardless of an individual’s CD4 (or T cell) count. Non-AIDS-defining cancers can be present in an individual with HIV and do not signify that they have progressed to AIDS.
AIDS-defining cancers include:
- Kaposi sarcoma: Cancer of the cells that line the blood vessels or lymph vessels. Caused by human herpesvirus 8 (HHV-8) which can be found in the saliva and passed from person to person. Kaposi sarcoma causes brown or dark purple spots on the mouth or skin. It can also be found inside the body in areas like the liver, spleen, lymph nodes, and digestive tract.
- Non-Hodgkin lymphoma (NHL): Cancer that starts in the tissues of our immune system (lymphoid tissue) and can spread to other organs or parts of the body. A common NHL found in individuals with AIDS is primary central nervous system (CNS) lymphoma, which involves the brain and/or spinal cord. Symptoms of CNS lymphoma include confusion, tiredness, memory loss, seizures, and facial paralysis. Other NHLs include Burkitt lymphoma and diffuse large B-cell lymphoma.
- Invasive cervical cancer: Cancer of the lower uterus (cervix) in women. A common cause of cervical cancer is the human papilloma virus (HPV) that can be spread during sex or through rough skin-to-skin contact. An early warning sign of cervical cancer may be detected and treated before an individual progresses to invasive cervical cancer. This early abnormal growth stage is called cervical intraepithelial neoplasia (CIN) and can be detected on a Pap smear or Pap test, a commonly performed screening test.1-3
Non-AIDS-defining cancers include:
- Lung cancer
- Liver cancer
- Mouth or throat cancers
- Hodgkin lymphoma (Hodgkin disease)
- Anal cancer
- Melanoma, squamous cell, or basal cell skin cancers
- Testicular cancer1-3
Prevention of cancer
The development of cancer is multifactorial, meaning that it happens due to a variety of issues that can all be occurring at the same time. In many cases, we may not know the exact cause of an individual’s cancer. Because of this, there is no guaranteed way to prevent cancer; however, there are steps that can be taken to reduce the chances of developing it.
Several of these include taking ART exactly as prescribed (every day) in order to keep the immune system as strong as possible and keep cancer-causing viruses away, avoiding behaviors that may increase an individual’s risk of getting a cancer-causing virus (such as avoiding unprotected sex or sex with multiple partners), avoiding common cancer-causing agents such as tobacco products and excessive alcohol intake, regularly checking in with a healthcare provider for necessary screening tests, and practicing positive health behaviors like healthy eating and exercise.2
Cancer treatment
Cancer treatment is complex and requires its own medical specialty (oncology). The treatment of an individual’s cancer depends on the type of cancer they have, its location or severity, specific features of the cancer cells present (such as what genes the cancer cells have), other medical conditions the person has, other medications they’re taking, personal preferences, and more.
Common treatment options for cancers include chemotherapy (medications used to target cancer cells), radiation therapy, and surgery. If you or a loved one is facing a cancer diagnosis, a healthcare team can help determine what treatment options are the most appropriate and beneficial in your situation.4