- Category: Cancer/Malignancies
- Published on Thursday, 14 April 2011 22:58
- Written by Liz Highleyman
AIDS-related cancers are now less common, but people with HIV are at higher risk for some non-AIDS cancers, especially those linked to infectious viruses.
Since the advent of effective antiretroviral therapy (ART), rates of AIDS-defining malignancies -- Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer -- have decreased dramatically. But as people with HIV live longer, they have more time to develop progressive cancers that are not considered to be AIDS-related.
As described in the April 11, 2011, advance online edition of the Journal of the National Cancer Institute, Meredith Shiels and colleagues from the National Cancer Institute and Centers for Disease Control and Prevention (CDC) estimated the yearly number of cancer cases in the HIV positive population -- both with and without AIDS -- in the U.S.
The researchers obtained incidence rates for specific cancer types from the HIV/AIDS Cancer Match Study by linking data from 15 U.S. HIV and cancer registries. Estimated numbers of people living with HIV or having a diagnosis of AIDS were gathered from CDC surveillance data. Data on people with HIV but not AIDS came from 34 states with name-based HIV reporting during 2004-2007.
The study authors then calculated estimated numbers of AIDS-defining and non-AIDS-defining cancer cases during 1991-2005 by multiplying cancer incidence rates and HIV/AIDS population counts, stratified by year, age, sex, race/ethnicity, and HIV transmission risk category.
- The number of people with AIDS in the U.S. grew 4-fold from 1991 to 2005, increasing from 96,179 to 413,080.
- This increase was largely due to a growing number of people age 40 and older in this population.
- During 1991-2005, an estimated 79,656 total cases of cancer occurred among people with AIDS.
- Between 1991-1995 and 2001-2005, the estimated number of AIDS-defining cancers decreased by more than 3-fold, from 34,587 to 10,325 cases.
- In contrast, non-AIDS-defining cancers increased by approximately 3-fold, from 3193 to 10,059 cases.
- From 1991-1995 to 2001-2005, estimated case numbers increased for several specific types of non-AIDS cancer:
- Anal cancer: 206 to 1564 cases;
- Liver cancer: 116 to 583 cases;
- Prostate cancer: 87 to 759 cases;
- Lung cancer: 875 to 1882 cases;
- Hodgkin lymphoma: 426 to 897 cases.
- Anal cancer, liver cancer, lung cancer, and Hodgkin lymphoma together comprised nearly half of all cancers diagnosed in this population during 2001-2005.
- Among people with HIV but not AIDS, an estimated 2191 non-AIDS-defining cancers occurred during 2004-2007, the most common being:
- Lung cancer: 454 cases;
- Breast cancer: 166 cases;
- Anal cancer: 154 cases.
Based on these findings, the study authors concluded, "Over a 15-year period (1991-2005), increases in non-AIDS-defining cancers were mainly driven by growth and aging of the AIDS population."
"Our study observed striking increases for a number of malignancies related to cancer risk factors that are known to be prevalent in this population, such as smoking and infection with cancer-causing viruses," said Shiels in a press release issued by the National Cancer Institute. "We also observed increases for nearly all other cancers, which is what one might expect for an aging population."
Several other studies have shown that not only have non-AIDS cancer rates increased over time among people with HIV/AIDS, but HIV positive people are also more likely to develop certain types of non-AIDS cancer than HIV negative people.
It is notable that the types of cancer that rose the most in this study, and that have the greatest increased risk for people with HIV, are generally those linked to infectious viruses. Hepatitis B and C viruses can cause liver cancer, Epstein-Barr virus can cause Hodgkin lymphoma, and prostate cancer has been linked to xenotropic murine leukemia virus-related virus (XMRV).
The same high-risk types of human papillomavirus (HPV) cause both cervical and anal cancer, although one is considered AIDS-defining and the other is not (due to pressure from activists in the 1980s-90s to include HIV/AIDS manifestations in women). HPV also causes mouth and throat cancers.
Lung cancer has not traditionally been considered an infectious cancer, but an intriguing study presented at the recent American Association for Cancer Research meeting in Orlando showed that people with lung cancer were significantly more likely to have antibodies against several high-risk HPV types. This link was seen in smokers and non-smokers alike. "We know that HPV can reach the lung, but whether HPV can cause frank malignancies is a question we hope to answer," said lead investigator Devasena Anantharaman.
The fact that people with HIV are at increased risk for cancers with an infectious cause indicates that compromised immune function -- even among individuals on ART with relatively high CD4 counts -- may be less able to control oncogenic viruses.
Investigator affiliations: Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD; Infections and Immunoepidemiology Branch and Biostatistics Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA; Office of HIV and AIDS Malignancy and Center for Cancer Research, National Cancer Institute, Bethesda, MD.
MS Shiels, RM Pfeiffer, MH Gail, et al. Cancer Burden in the HIV-Infected Population in the United States. Journal of the National Cancer Institute (abstract). April 11, 2011 (Epub ahead of print).
D Anantharaman, M Pawlita, T Waterboer, et al. Human papillomavirus serology and the risk of lung cancer. 102nd Annual Meeting of the American Association for Cancer Research. Orlando. April 2-6, 2011. Abstract 1890.
National Cancer Institute. Distribution of cancers in the HIV/AIDS population is shifting. NIH News. April 11, 2011.
CDC. Lung Cancer Patients More Likely to Have High-Risk Human Papillomavirus. CDC HIV/Hepatitis/STD/TB Prevention News Update. April 12, 2011.