The epidemiology of conjunctival squamous cell carcinoma in Uganda

Abstract

As part of a larger investigation of cancer in Uganda, we conducted a case -control study of conjunctival squamous cell carcinoma in adults presenting at hospitals in Kampala. Participants were interviewed about social and lifestyle factors and had blood tested for antibodies to HIV, . The odds of each factor among 60 people with conjunctival cancer was compared to that among 1214 controls with other cancer sites or types, using odds ratios, estimated with unconditional logistic regression. Conjunctival cancer was associated with HIV infection (OR 10.1, 95% confidence intervals [CI] 5.2 -19.4; P50.001), and was less common in those with a higher personal income (OR 0.4, 95% CI 0.3 -1.2; P50.001). The risk of conjunctival cancer increased with increasing time spent in cultivation and therefore in direct sunlight (w 2 trend=3.9, P=0.05), but decreased with decreasing age at leaving home (w 2 trend=3.9, P=0.05), perhaps reflecting less exposure to sunlight consequent to working in towns, although both results were of borderline statistical significance. To reduce confounding, sexual and reproductive variables were examined among HIV seropositive individuals only. Cases were more likely than controls to report that they had given or received gifts for sex (OR 3.5, 95% CI 1.2 -10.4; P=0.03), but this may have been a chance finding as no other sexual or reproductive variable was associated with conjunctival cancer, including the number of self-reported lifetime sexual partners (P=0.4). The seroprevalence of antibodies against HPV-18 and -45 was too low to make reliable conclusions. The presence of anti-HPV-16 antibodies was not significantly associated with squamous cell carcinoma of the conjunctiva (OR 1.5, 95% CI 0.5 -4.3; P=0.5) and nor were anti-KSHV antibodies (OR 0.9, 95% CI 0.4 -2.1; P=0.8). The 10-fold increased risk of conjunctival cancer in HIV infected individuals is similar to results from other studies. Squamous cell carcinoma of the conjunctiva is thought to be an extreme form of a spectrum of clinical conditions, collectively known as 'ocular surface squamous neoplasias', which range in severity from mild dysplasia, to carcinoma in situ and, ultimately, to invasive carcinoma. Symptoms can range from none, to severe pain and visual loss. Lesions generally arise on exposed areas of the eye, particularly on the nasal side, and treatment involves local excision, or in more severe cases, orbital clearance. Metastases are rare and the prognosis is usually favourable.Although relatively rare everywhere, conjunctival carcinoma is more frequent in parts of sub-Saharan Africa. Uganda offers a good setting in which to investigate the epidemiology of squamous cell carcinoma of the conjunctiva, because the tumour was relatively frequent there, even before the onset of the HIV epidemic (Templeton, 1973;Wabinga et al, 2000). In this report, we examine the association of conjunctival tumours with over 50 possible risk factors, including evidence of infection with HIV-1, HPV-16, -18 and -45 and Kaposi's sarcoma-associa...

Evaluating the role of human papillomaviruses in conjunctival neoplasia

“…Although rare in Europe and USA, conjunctival neoplasia has been reported to be relatively common in regions of sub-Saharan Africa since the 1960s (Templeton, 1973). An emerging miniepidemic of conjunctival tumours has been described in Rwanda, Uganda and Tanzania in association with the epidemic of HIV infection since the 1980s (AteenyiAgaba, 1995;Waddell et al, 1996;Newton et al, 2002). The spread of HIV in Uganda, indeed, probably accounts for much of the approximately eight-fold increase in the incidence of conjunctival carcinoma observed during the last 20 years (Wabinga et al, 2000).…”

Spectrum of cancers among HIV‐infected persons in Africa: The Uganda AIDS‐Cancer Registry Match Study

“…13,18 However, these studies have observed a novel association of HIV infection with conjunctival cancer. 19 Cohort studies have not been used to study risk of cancer among persons with HIV/AIDS in Africa.…”

The Viral Etiology of AIDS‐Associated Malignancies

“…HPVs are most commonly associated with cervical cancer, although, it is now known that many cancers are induced by HPV, including penile, anal, oral, and conjunctival cancers (Durst et al, 1983;Koutsky, 1997;Newton et al, 2002;Syrjanen, 2003;Waddell et al, 1996). High-risk HPVs have also been implicated recently in ~30% of oral cancers (Gillison et al, 2000).…”

“…HPV infections of the conjunctiva of the eye are more common than previously appreciated, although resulting HPV-induced tumors of the conjunctiva are very rare (Mincione et al, 1992(Mincione et al, , 2006Reszec and Sulkowski, 2005;Tabrizi et al, 1997;Waddell et al, 2003). Though the incidence of eye or eye-orbit tumors in the United States is extremely low (<1/100,000) (Gloeckler Ries et al, 2003), in African countries, conjunctival tumors are more common and are undoubtedly influenced by nutrition, additional disease burdens, but most obviously by the relatively high impact of HIV in Africa (Ateenyi- Agaba et al, 2006;Frisch et al, 2000;Goedert, 2000;Newton et al, 2002;Waddell et al, 1996Waddell et al, , 2003.…”