Page 136 - AIDSBK23C

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Particularly among males having anal intercourse, there is an increased incidence of
anorectal epithelial dysplasias and anorectal squamous carcinomas. Penile cancer is more
frequent in AIDS, but the association is not strong.[544] Human papillomavirus (HPV) infection
plays a major role in development of these lesions in males and females. Squamous epithelial
carcinomas in AIDS are more likely to be multifocal and extensive and more difficult to
treat.[591]
The risk for development of skin cancers appears to be increased in HIV-infected
individuals. Persons with AIDS tend to have a higher risk for development of basal cell
carcinoma than the general population, and basal cell carcinoma is the second most common skin
cancer in AIDS patients, with an incidence of 1.8%, compared to an overall incidence of
cutaneous Kaposi’s sarcoma of 6.2%. In HIV-infected persons, basal cell carcinomas tend to be
superficial, multicentric, and located on the trunk. The degree of immunosuppression does not
appear to play a role in the appearance of this neoplasm.[591,592]
Dysplastic nevi and melanoma have been reported in HIV-infected patients with no prior
family history of melanocytic lesions. The median age appears to be lower, and there is a greater
tendency for thicker lesions with early metastasis, compared to non-HIV-infected persons,
particularly when the CD4 lymphocyte count is lower.[591,592]
Lung cancers are seen with increased frequency in association with HIV infection,
accounting for 5% of all deaths, and 15% of cancer-related deaths. HIV-infected persons get
lung cancers at a younger median age, and they are most likely to have an adenocarcinoma, and
overall non-small cell carcinomas account for 67 to 86% of cases, while small cell anaplastic
carcinomas in this population are much less common than in the general population. The most
important risk factor is smoking, but lung cancer risk does not appear to be associated with a
reduction in CD4 lymphocyte count or antiretroviral therapy. Over 80% of HIV-infected
patients with lung cancer present with advanced stage III or IV lesions that are
inoperable.[592,593] Chronic and recurrent pulmonary infections, including those with
Mycobacterium and Pneumocystis, may contribute to lung carcinogenesis.[594]
Colonic adenocarcinoma in HIV-infected persons tends to be more aggressive. The
average age at diagnosis is 43 years (range 25-67). Most of these cancers arose in males and
most involved the right colon. Half were TNM stage 4. Half of affected persons died within 1-
26 months.[595]
The relative preponderance of young males infected with HIV increases the likelihood for
appearance of testicular neoplasms, since this is the most common solid malignant neoplasm in
young males. There is a relative risk of 2 in HIV-infected males compared with matched
controls.[544] Most cases of testicular cancer occur before the stage of clinical AIDS has been
reached. The stage at diagnosis is similar to non-HIV-infected persons, and response to therapy
is also similar.[592,596].
Non-AIDS malignancies seen in association with HIV infection are likely to be
coincidental, and longer survival of HIV-infected patients increases the likelihood for appearance
of neoplasms. Benign neoplasms are not seen with increased frequency in patients with AIDS.
The overall incidence of non-AIDS-defining neoplasms (those not part of criteria for AIDS) does
not appear to be high, with an incidence of 2% in a study of over 11,000 patients followed from
1996. About half are related to infections. No significant effect of viremia was seen. Cumulative
exposure to CD4+ cell counts <200 cells/microliter during antiretroviral therapy was associated
with an increased risk of infection-related non-AIDS-defining malignancies.[597]