A large and well-conducted study on the risk of developing cancer has just been published. In recent years, cancer has become more common among people living with HIV (PLWH) – partly because PLWH are living longer. HIV’s impact on the immune system also contributes to high cancer rates. The researchers looked at data on 86,620 people living with HIV in the US and Canada, comparing them with almost 200,000 people who don’t have HIV. The data come from 1996 to 2009, so include some people taking older and less effective HIV treatments. The researchers give figures for the proportion of people who have different cancers by the age of 75. The two cancers which most commonly affect people with HIV are:
- Non-Hodgkin lymphoma (a cancer of the lymph nodes and lymphatic system) – 4.5% of PLWH have this by the age of 75, versus 0.7% of HIV-negative people.
- Kaposi’s sarcoma (a cancer which can cause skin lesions) – 4.4%, versus 0.01% of HIV-negative people.
PLWH are vulnerable to the infections which cause these cancers when their immune system is weakened. Beginning HIV treatment early is the best way to avoid them – and helps with other cancers too. The risk of these two cancers has declined since the earlier years of the epidemic, but rates are still far higher than in the general population.
The third most common cancer is:
- Lung cancer – 3.4% in PLWH, versus 2.8% in HIV-negative people.
The main cause of lung cancer is smoking. Surveys show that more PLWH smoke than in the general population – the researchers say that services to help people with HIV stop smoking are a priority. They also recommend lung cancer screening.
The next two cancers are:
The risk of these has increased in recent years. This is because PLWH are living longer and so have a greater risk of developing diseases other than HIV. Also, PLWH have high rates of the infections which cause these cancers – human papillomavirus (HPV), hepatitis B and hepatitis C. Vaccination and treatment for these infections can help prevent cancer.
Rates of other cancers were not always higher in PLWH:
- Bowel cancer – 1.0% versus 1.5%.
- Hodgkin lymphoma (another cancer of the lymph nodes and lymphatic system) – 0.9% versus 0.09%.
- Mouth and throat cancer – 0.8% versus 0.8%.
- Melanoma skin cancer – 0.5% versus 0.6%.
The researchers think that three things need to be prioritised so that fewer people with HIV develop cancers – early HIV treatment, smoking cessation and lung cancer screening.