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Invasive Anal Cancer Seen With Relatively High CD4s and Low HIV Loads
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Download the PDF here
18th Conference on Retroviruses and Opportunistic Infections, February 27-March 2, 2011, Boston
Mark Mascolini
Most cases of invasive anal cancer in a study of 121 HIV-positive Germans arose in people with only moderately low CD4 counts and often with undetectable viral loads.1 But half of these people had a nadir CD4 count under 100, and half had a history of Condylomata acuminata, genital warts caused by human papillomavirus (HPV).
Because research suggests a rising incidence of invasive anal cancer (a non-AIDS cancer) in people with HIV, collaborators from several German centers retrospectively analyzed all cases of biopsy-proved invasive anal cancer seen at these clinics from January 2000 to December 2010. They excluded cases of in situ anal cancer and calculated overall survival according to use of antiretroviral therapy, anal cancer therapies, and prognostic factors.
Of the 121 cases, only 4 (3%) affected women. Age of the study group averaged 48.2 years, and an average of 11.9 years had passed since these people tested positive for HIV. Fifty-four of 117 people (46%) had an AIDS diagnosis, and 68 of 88 (77%) were active or former smokers. Squamous cell carcinoma was the most common type of anal cancer, affecting 101 people (83%). Fifty-two of 102 people (51%) had a history of Condylomata acuminata, and 17 of 93 people (18%) had a history of dysplasia (precancerous cells).
Among 111 people whose anal cancer was staged, 35 (32%) had stage 1, 47 (42%) had stage 2, 27 (24%) had stage 3, and 2 (2%) had stage 4. Among 120 people analyzed for antiretroviral use, 12 (10%) had never taken antiretrovirals, 10 (8%) had taken antiretrovirals earlier, and 98 (82%) were currently taking antiretrovirals. Among 94 people with viral load data available, 86 (91%) had fewer than 500 HIV RNA copies/mL and 66 (70%) had fewer than 50.
Current CD4 count averaged 397 (range 15 to 1210), and 20% of these people had a current CD4 count under 200. CD4 percent averaged 19 (range 4 to 40). Lowest-ever (nadir) CD4 count averaged 125 (range 3 to 462). Half of these people had a nadir CD4 count below 100.
Through an average 3.78 years of follow-up, 26 people with invasive anal cancer (21%) died. Clinicians considered anal cancer the main cause of death in 18 of these people. Multivariate analysis to identify predictors of anal cancer death eliminated people with no therapy or only surgical therapy for anal cancer, or with incomplete data on anal cancer therapy. In this analysis, having stage 1 or 2 cancer lowered the risk of anal cancer death about 75% (hazard ratio 0.23, 95% confidence interval 0.07 to 0.77, P = 0.02). Performance score, chemotherapy plus radiation, and a CD4 nadir above 100 did not independently affect the risk of anal cancer death.
The investigators concluded that "currently, most cases of invasive anal cancer occur in the setting of only limited immune deficiency and viral suppression." They believe their findings "emphasize the need for validated screening methods in all HIV-infected patients." This poster is online at the link provided in the reference.
In the United States, Gardasil, an HPV vaccine, has been licensed to prevent anal, cervical, and other cancers in 9- to 26-year-olds of both genders (http://www.gardasil.com/). The National Institutes of Health lists the following risk factors for genital warts: (1) having multiple sex partners, (2) not knowing whether someone you had sex with had sexually transmitted infections, (3) becoming sexually active at an early age, (4) using tobacco and alcohol, (5) having stress and other viral infections (such as herpes) at the same time, (6) being pregnant, (7) having an immune system that does not work well, such as during cancer treatment or AIDS.2
References
1. Hoffmann C, Sabranski M, Wyen C, et al. Clinical characteristics and outcome of HIV+ patients with invasive anal cancer. 18th Conference on Retroviruses and Opportunistic Infections. February 27-March 2, 2011. Boston. Abstract 870.
http://www.retroconference.org/2011/PDFs/870.pdf.
2. PedMed Health. National Institutes of Health. Genital warts.
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001889/.
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