Michael Carter for Aidsmap (6 September 2010 )
Recurrent bacterial pneumonia is associated with an increased risk of lung cancer in patients with AIDS, US investigators report in the online edition of the Journal of Acquired Immune Deficiency Syndromes. The association between pneumonia and lung cancer was especially strong amongst patients below 50.
The investigators believe that recurrent pneumonia could be causing inflammation, which in turn increases the risk of lung cancer.
Amongst people with AIDS in the US, lung cancer is the third most common cancer. Cigarette smoking has been identified as the only factor significantly associated with lung cancer risk for people with HIV in a number of studies. However, a team of US investigators found that even after adjusting for cigarette smoking, lung cancer risk was still elevated amongst people with HIV.
People with HIV, especially if they have a weak immune system, are more likely to develop serious lung disease. Three types of pulmonary disease are classified as AIDS-defining: PCP pneumonia; tuberculosis (TB); and recurrent bacterial pneumonia.
Investigators hypothesized that individuals with AIDS who developed these diseases would be at increased risk of lung cancer, because of the inflammation that they cause in the lungs.
They therefore looked at the records of 322,675 individuals who were diagnosed with AIDS between 1977 and 2002 and linked these to cancer registries. They monitored the patients’ risk of lung cancer in the ten years after their diagnosis with AIDS.
The investigators comment: “We found that individuals with recurrent pneumonia had a significantly increased risk of lung cancer…our current observation that recurrent pneumonia was associated with increased lung cancer risk among younger, but not older PWA supports the conclusion that pulmonary infections might explain the high lung cancer risk among young PWA.”