HTB South

Outcomes from screening study for anal cancer in HIV-positive compared to HIV-negative patients

Simon Collins, HIV i-Base

A recent paper in the September 2009 issue of Gut reported significantly poorer diagnostic results from colonoscopy screening in HIV-positive compared to HIV-negative controls. This included higher prevalence of lesions, larger and more advanced lesions and that these were occuring at a younger age in the HIV-positive group.

Bini and colleagues from New York performed coloscopy screening for colonic neoplasms in 136 asymtomatic HIV-positve men older than 50 years and 272 HIV-negative controls matched for age, sex and family history. All participants were patients at a single VA site, with screening performed from 2002-2004. Exclusion criteria included previous screening (5-10 years) or positive faecal occult blood test.

The median duration of infection in the HIV-positive groups was 11 years (IQR 7-14), median CD4 count was 346 cells/mm3 (IQR, 236-707) and around 90% were on HAART, 73% of who had had undetectable viral load.

The study found a significantly higher prevalence in HIV-positive patients (62.5% vs 41.2% (p<0.001). This remained highly significant after adjustment for potential confounding variables, including age, sex, race/ethnicity, current alcohol use, current smoking, use of NSAIDs and aspirin, family history of colorectal cancer and history of screening.

Compared with control subjects, HIV-positive patients had significantly increased odds of having a neoplastic lesion (OR = 2.38; 95% CI, 1.56 to 3.63). This association remained highly significant after adjustment baseline characteristics (OR = 3.00; 95% CI, 1.83 to 4.93) and after further adjustment for tobacco, alcohol, aspirin and NSAIDs (OR = 2.84; 95% CI, 1.74 to 4.62).

Compared with controls, HIV-infected patients were significantly less likely to have hyperplastic (benign) polyps and were more likely to have adenomas 6-9 mm in diameter. More HIV-infected subjects than control subjects had two or more adenomas detected (41.2% vs 30.9%, p = 0.04).

Among the 11 adenocarcinomas that were diagnosed, HIV-positive patients were significantly younger than those without HIV (52.4 (SD 1.3) vs 60.3 (SD 4.0) years, p = 0.002), a difference of 7.9 (95% CI, 3.6 to 12.2) years. Late-stage adenocarcinoma of the colon (stage III or IV) was more common in HIV-positive subjects (3/5 (60.0%)) than in controls (1/6 (16.7%)), although this difference was not statistically significant (p = 0.24).

The study found no association between neoplastic lesions of the colon and duration of HIV infection, CD4 count, or viral load, but a protective effect was reported in HIV-positive people on HAART (OR = 0.13; 95% CI, 0.02 to 1.02).

The authors concluded that their findings suggest that screening colonoscopy should be offered to HIV-positive patients, although the age of initiation and the optimal frequency of screening require further study.

comment

These add to the growing evidence supporting a screening programme for HIV-positive people as a targeted high risk group. See coverage in the EACS conference report earlier in this issue of HTB. [2]

References:

  1. Bini EJ et al. Screening colonoscopy for the detection of neoplastic lesions in asymptomatic HIV-infected subjects: more colon lesions in HIV+. Gut Sept 2009;58:1129-1134.
    http://www.natap.org/2009/HIV/100809_03.htm
  2. Bower M. Screening for non-AIDS malignancies: if and how? 12th EACS, 11-14 November 2009, Cologne. Webcast:
    http://www.multiwebcast.com/eacs/2009/12th/4149

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