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Rates of 2 Non-AIDS Cancers Higher With HIV in British Columbia Women
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7th IAS Conference on HIV Pathogenesis, Treatment and Prevention, June 30-July 3, 2013, Kuala Lumpur
Mark Mascolini
A province-wide analysis of new cancer diagnoses in HIV-positive women of British Columbia determined that two non-AIDS cancers arose significantly more often in these women than in the general population [1]. Higher viral load and lower CD4 count correlated with cancer risk in women with HIV. Mortality was 2.6 times higher in HIV-positive women with than without cancer.
Cancer rates and risks are being thoroughly studied in people with HIV, but few studies have focused solely on HIV-positive women. Researchers in British Columbia (BC) addressed that lack by creating a retrospective population-based 1994-2008 database. To do so, they linked two province-wide databases--the BC Cancer Registry and the BC Centre for Excellence in HIV/AIDS. They aimed to identify new cancer diagnoses in HIV-positive women at least 19 years old from the time they started HIV care in BC. The analysis eliminated 32 cases of cervical intraepithelial neoplasia, a cervical cancer precursor.
The investigators used bivariate analysis to compare HIV-positive women with and without cancer according to several clinical or sociodemographic variables. They calculated standardized incidence ratios for selected cancers to compare age-standardized rates in women with HIV and the general population.
This analysis identified 78 new cancers in 2211 women (3.5%) with HIV--46 AIDS cancers (59%) and 32 non-AIDS malignancies. Among AIDS cancers, there were 22 cervical cancers, 19 non-Hodgkin lymphomas, and 5 cases of Kaposi sarcoma. Non-AIDS cancers included 7 lung/bronchial cancers, 7 breast cancers, 3 Hodgkin lymphomas, 2 cases each of urinary, vulvar, or rectal/anal cancer, and 1 case each of mesothelioma or cancer of the gum/mouth, soft tissue, corpus uteri, thyroid, skin, or liver, and 2 other or unknown cancers.
Overall cancer incidence was 0.62 per 100 person-years, meaning about 6 in 1000 women with HIV got diagnosed with cancer every year. Median age and CD4 count at cancer diagnosis were 40 years (interquartile range [IQR] 32 to 48) and 150 (IQR 40 to 259).
Six clinical variables differed significantly between HIV-positive women with and without a new cancer diagnosis: baseline AIDS-defining illness (16.7% versus 5.9%, P < 0.001), median baseline CD4 count (140 versus 350, P < 0.001), median nadir CD4 count (50 versus 150, P < 0.001), median baseline viral load (100,010 versus 54,000 copies, P = 0.001), median peak viral load (100,010 versus 69,000, P = 0.023), and mortality (46.2% versus 17.5%, P < 0.001). Factors that did not correlate with cancer incidence in this analysis were age, ethnicity, injection drug use history, or hepatitis C virus positivity.
Standardized incidence ratios (SIRs) indicated that two non-AIDS cancers and two AIDS cancers were significantly more likely in women with HIV than in the general population--genital tract cancer (SIR 4.2, 95% confidence interval [CI] 2.7 to 6.2), Hodgkin lymphoma (SIR 11.5, 95% CI 2.4 to 33.7), non-Hodgkin lymphoma (SIR 9.1, 95% CI 5.5 to 14.1), and Kaposi sarcoma (SIR 500.0, 95% CI 162.4 to 1166.8). One non-AIDS cancer, breast cancer, was half as likely in women with HIV as in the general population (SIR 0.5, 95% CI 0.2 to 0.9).
The researchers noted that their analysis is limited by lack of information on cancer risk factors such as family history, smoking, and alcohol use. With that caveat in mind, they concluded that the higher risk for certain cancers in HIV-positive women than in the general population suggests "the need to prospectively monitor women living with HIV for cancer and ensure careful attention to existing cancer screening guidelines." Because low CD4 count and high viral load emerged as important cancer risk correlates, the BC team proposed that "improved HIV treatment" may have a positive impact on cancer risk.
Reference
1. Cescon A, Salters KA, Zhang W, et al. Increased risk of cancer among HIV-positive women in British Columbia, Canada: importance of targeted screening and detection programs. 7th IAS Conference on HIV Pathogenesis, Treatment and Prevention, June 30-July 3, 2013, Kuala Lumpur. Abstract WEPE506.
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