HIV increases the risk of lung cancer, independent of smoking status
2 April 2010. Related: Conference reports, Cancer and HIV, CROI 17 (Retrovirus) 2010.
Simon Collins, HIV i-Base
Keith Sigel and colleagues presented an analysis from the US Veterans Ageing Cohort Study Virtual Cohort (VC) on the relationship between HIV and lung cancer. [1]
The advantages of this database included size, smoking status data from a related health survey and a matched HIV-negative control group, although this was an almost exclusively (98%) male study. Median age was 47 years and ethnicity was approximately 40% white, 40% black. 10% Hispanic and 10% other. Approximately 30% were current smokers, 15% recently quit (< 1 year), 25-50% distantly quit (> 1 year) and 20% of HIV-positive compared to 25% of HIV-negative had never smoked.
The analysis compared over 3,700 HIV-positive and nearly 10,000 HIV negative patients (contributing 28,500 and 76,800 person-years of follow-up respectively).
Lung cancer was defined using International Classification of Diseases (ICD-9) codes and Incidence Rate Ratios (IRR) were adjusted for age, race, smoking exposure, and Chronic Obstructive Pulmonary Disease (COPD).
The overall incidence of lung cancer per 100 person years was 0.26 compared to 0.16 in the HIV positive vs HIV negative groups (unadjusted IRR 1.5, 95%CI 1.2–2.0). Results from the adjusted analysis are detailed in Table 1.
Table 1: Adjusted IRR for lung cancer multivariate model including all covariates
| Variable | IRR | 95% CI |
| HIV infection | 1.8 | 1.3–2.4 |
| Age | 1.1 | 1.1–1.1 |
| Race/ethnicity: *African-American
Hispanic Other |
0.9
0.4 0.9 |
0.7–1.2
0.2–0.8 0.5–1.6 |
| COPD | 1.5 | 1.1–2.1 |
| Smoking exposure: **Current daily smoker
Current occasional smoker Recently quit smoking (<1 yr) Distantly quit smoking (>1 yr) |
9.8
3.4 9.9 5.1 |
4.4–21.4
1.0–11.6 4.4–22.3 2.4–11.2 |
* Reference = white race; ** Reference = never smoked.
The authors concluded that the incidence of lung cancer was significantly increased in HIV-positive men in their group, even after adjusting for smoking exposure.
comment
This study reported slightly lower rates of increased risk of lung cancers in HIV positive individuals compared to rates that were 2- to 6-fold higher in earlier studies, that also adjusted for smoking status. [2, 3, 4]
While the approximate 2-fold increased risk associated with HIV was significant and is important, the presenter emphasised the 10-fold higher risk for current smokers (that was halved to around 5-fold for former smokers who had quit more than one year earlier).
References
Unless stated otherwise, all references are to the Programme and Abstracts of the 17th Conference on Retroviruses and Opportunistic Infections. 16-10 February 2010, San Francisco. All oral abstracts are available as webcasts.
http://www.retroconference.org
- Sigel K et al. HIV infection is an independent risk factor for lung cancer. 17th CROI, 2010. Oral Abstract 30.
http://www.retroconference.org/2010/Abstracts/38365.htm - Cadranel J et al. Lung cancer in HIV infected patients: facts, questions and challenges. Thorax 2006; 61:1000-1008.
http://thorax.bmj.com/content/61/11/1000.abstract - Engels EA et al. Elevated incidence of lung cancer among HIV-infected individuals. J Clin Oncol 2006; 24 (9); 1383-1388. (March 2006).
http://jco.ascopubs.org/cgi/content/abstract/24/9/1383 - Kirk GD et al. HIV infection is associated with an increased risk for lung cancer, independent of smoking. Clin Inf Dis 2007; 45:103-110.
http://www.journals.uchicago.edu/doi/abs/10.1086/518606