Lung cancer

Lung cancer is not an AIDS-defining illness. However, people with HIV have a greater chance of developing lung cancer than non-infected people, and as people with HIV live longer due to antiretroviral therapy, more cases of lung cancer are likely to occur in the presence of HIV infection.

A number of studies have shown that lung cancer is more common in HIV-positive patients, and that it tends to occur at a younger age. For example, American researchers reviewed cancer and HIV registers in Texas between 1990 and 1995, and found that people with HIV had a 6.5-fold greater risk of lung cancer than non-infected people and a 13.6-fold greater risk of any lung malignancy. In New York, an HIV cohort had three times the risk of lung cancer compared to the general American population.1 Further evidence of an increased risk of lung cancer among HIV-infected people was produced by a meta-analysis of cancer incidence studies in HIV-positive people, which found a higher incidence compared to the general population.2

These trends have also been demonstrated in American women,3 in US male veterans,4 and in three large US HIV cohorts.5 6 The only anomalous finding, from the Women's Interagency HIV Study (WIHS), was that HIV status had no effect on lung cancer risk in a cohort of HIV-positive and HIV-negative women, many of whom were heavy smokers: smoking was the sole risk factor identified.7

HIV was found to increase the risk of lung cancer by 80% in a large study of US veterans.8 Some studies have also found low nadir CD4 cell count to be a risk factor in HIV-positive people,9 and a history of recurrent pneumonia has been linked to increased risk of lung cancer in people diagnosed with AIDS.10 However, the most important risk factor for lung cancer is smoking, which the US veterans study found greatly outweighed the risk due to HIV. 

There is also evidence that lung cancer is more aggressive among people with weakened immune systems. There are a number of theories to explain this observation: low numbers of natural killer cells may lead to the proliferation of abnormal cells, or abnormal growth factors may be stimulated by HIV. Regardless of the cause, studies have shown that people with HIV have a worse prognosis than non-infected people, with an average survival time of five months in HIV-positive people, and ten months in the general population.11

In the United Kingdom, the incidence of lung cancer among HIV-infected people in south-east England appears to be well above the rate for the general population when matched by age and sex.12 Since the introduction of combination therapy, the incidence of lung cancer among HIV-infected people in England has risen significantly.

See also Cancer.

References

  1. Ricaurte JC et al. Lung cancer in HIV-infected patients: a one-year experience. International Journal of STDs and AIDS 12(2): 100-102, 2001
  2. Grulich A Incidence of cancers in people with HIV/AIDS compared with immunosuppressed transplant recipients: a meta-analysis. The Lancet 370: 59-67, 2007
  3. Phelps R et al. Cancer incidence in women with or at risk for HIV. International Journal of Cancer 94(5): 753-757, 2001
  4. Bedimo RJ et al. Incidence of non-AIDS-defining malignancies in HIV-infected vs. non-infected veterans in the HAART era: impact of immunosuppression. 47th Interscience Conference on Antimicrobial Agents and Chemotherapy, abstract H-1721, Chicago, 2007
  5. Patel P et al. Trends in cancer incidence among HIV-infected persons in the United States in the HAART era. Fourth International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention, abstract MOPEB082, Sydney, 2007
  6. Kirk GD et al. HIV infection is associated with an increased risk for lung cancer, independent of smoking. Clin Inf Dis 45(1):103-10, 2007
  7. Levine AM et al. HIV as a risk factor for lung cancer in women: data from the Women’s Interagency HIV Study. Journal of Clinical Oncology (online edition), 2010
  8. Sigel K et al. HIV infection is an independent risk factor for lung cancer. Seventeenth Conference on Retroviruses and Opportunistic Infections, abstract 30, San Francisco, 2010
  9. Patel P et al. Incidence of non-AIDS-defining malignancies in the HIV Outpatient Study. Eleventh Conference on Retroviruses and Opportunistic Infections, San Francisco, abstract 81, 2004
  10. Shebl FM et al. Pulmonary infections and risk of lung cancer among persons with AIDS. J Acquir Immune Defic Syndr, advance online publication, August 23, 2010., 2010
  11. Tirelli U et al. Impact of HAART on the clinical management of AIDS-related cancers. European Journal of Cancer 37(10): 1320-1324, 2001
  12. Powles T et al. Incidence and outcome of HIV-related lung cancer in the HAART era. Second International AIDS Society Conference on HIV Pathogenesis and Treatment, Paris (Antiviral Therapy 8:1), abstract 946, 2003