Immunosuppression And Cancer

Perhaps the greatest change in the nature and frequency of some orbital disorders has been in those that occur more frequently in the immunosuppressed patient. The treatment of many disorders, especially for those of an autoimmune type and for the immuno-suppression required for solid organ transplants, has involved general suppression of the immune system at the expense of an increased risk and incidence of formerly rare disorders.

Immunodeficiency may be congenital, therapeutic, or infectious [human immunodeficiency viruses (HIV)]. We have seen increases in the latter two, and in some parts of the world, HIV is the most prevalent and serious infectious disease in the community. Immunodeficiency increases the risk of some but not all cancers. The common feature of these cancers is that specific infectious agents may be important in their etiology; this may extend to a lesser extent beyond the immunodeficient population to the normal population. People with acquired immune deficiency syndrome (HIV/AIDS) are more susceptible to a variety of malignant neoplasms (see Table 3.1). These include

TABLE 3.1. Malignant Neoplasms of the Orbit and Ocular Adnexa Associated with AIDS.

Lymphoma

Small, non-cleaved cell (Burkitt) lymphoma

Large non-cleaved-cell immunoblastic

lymphoma

Hodgkin's lymphoma (rare)

Kaposi's sarcoma

Eyelid

Conjunctiva

Orbit (rare)

Squamous cell

Eyelid

carcinoma

Conjunctiva (common especially in Africa)

Kaposi sarcoma (which is associated with human herpes virus type 8 (HHV-8)), non-Hodgkin's lymphoma of the Burkitt type (associated with another herpesvirus, the Epstein-Barr virus (EBV)), and conjunctival squamous cell carcinoma (associated with human papilloma virus (HPV)). In some studies, however, HIV/AIDS has not been shown to lead to an increase in cervical cancer, which has a known association with HPV infection. This requires further study, as does the apparent lack of certain other cancers that might be expected to be increased in HIV/AIDS.8

Despite the worldwide epidemic of HIV/AIDS and the increased incidence of these cancers, there has been a relative paucity of cases of orbital non-Hodgkin's lymphoma. NHL in AIDS is typically higher grade, is extranodal, and has a poorer outcome. The first case of orbital involvement was reported in 19829 and the second as late as 1990.10 Since that time, a handful of other cases has been reported.11-13

Here then is a paradox. We have a worldwide epidemic of HIV/AIDS. There has been a documented increase in the incidence of NHL and, in particular, NHL of the orbit; but there have been very few cases of NHL of the orbit reported to be associated with AIDS. Our own experience has mirrored this. In a survey of 73 cases of orbital and ocular adnexal lymphoma from our institution, not one was known to be associated with HIV/AIDS.14 Other large series also show no cases of HIV/AIDS-associated NHL. NHL of the ocular adnexa typically occurs in the older population (median age 65 in our series),14 whereas NHL in association with HIV/AIDS occurs most commonly in the third decade, coinciding with the median decade in which AIDS is found.15 From a practical perspective, a younger patient with a higher grade lymphoma of the orbit probably should be tested for HIV, although the likelihood of a positive result is fairly low, and most cases reported have been in patients already known to have HIV/AIDS. Another large group of im-munodeficient patients are those receiving solid organ transplants. It is well recognized that this group is also more susceptible to a range of cancers and infections. Many of these are associated with particular viruses and may occur in the orbit or ocular adnexa.

Infection by HPV is well documented to increase after organ transplantation and the concomitant immunosuppression. The incidence of warts increases after transplantation, and at a later date, the incidence of squamous cell cancers of the skin also increases. Within these tumors can be found evidence of HPV of various types, often more than one type in each tumor.16

Within the first 5 years of immunosuppression, 40% of transplant recipients experience premalignant skin tumors such as actinic keratoses and Bowen's disease, as well as squamous cell carcinoma (SCC) and basal cell carcinoma (BCC).17 These tumors often have a more aggressive pattern of growth and atypical morphology.18 Sun exposure is a clear risk factor, and the presence of skin cancers or premalignant skin lesions may be a contraindication to organ transplantation because of the increased mortality associated with organ transplantation from cancer, including skin cancer. In addition to the association between immune suppression and HPV infection and the development of non-melanoma skin cancer, there is evidence of a link with herpes-like virus infection and skin cancers other than Kaposi sarcoma in transplant patients.19 In a group of non-AIDS immunocompromised patients, 82% of 33 skin lesions (BCC, SCC, actinic keratoses, etc.) demonstrated herpes virus-like sequences of DNA.

The incidence of skin cancers (other than Kaposi sarcoma) is also increased in patients whose immune system is compromised by the HIV/AIDS virus. A study from Italy found a threefold increase in non-melanoma skin cancer (mostly BCC) in AIDS patients.20 This increase in nonmelanoma skin cancer was noted to be less than that occurring in transplant patients. Cutaneous SCC is often more aggressive when it occurs in patients with HIV/AIDS,21 and such lesions should be managed aggressively rather than palliatively because they may be fatal, particularly with antiretroviral therapies now prolonging survival in HIV-infected patients for many years.22 Basal cell carcinoma may behave more aggressively in AIDS patients also. Although metastasis from BCC is extremely rare, it is documented to occur when cellular immunity is compromised, as occurs in AIDS.23 The commonest mucocutaneous malignancy associated with AIDS is Kaposi sarcoma, which is associated with infection with HHV-8. The condition may occur in the eyelids or conjunctiva but rarely affects the orbit.24 Conjunctival Kaposi sarcoma may be the presenting feature of AIDS, but by far the commonest conjunctival tumor associated with AIDS is SCC. This is particularly true for AIDS occurring in Africa, where conjunctival SCC is one of the commonest AIDS-associated cancers. In African HIV patients, non-Hodgkin's lymphoma may be less frequent than in the West.25 It is unclear whether this represents differences in prevalence of other associated viral infec tions. Because of the dramatic rise in incidence of AIDS, Kaposi sarcoma has emerged as the most common cancer in parts of Africa.26 Conjunctival SCC has dramatically increased in incidence in areas of Africa where AIDS is prevalent, and it behaves in a particularly aggressive manner.27 This dramatic rise in SCC of the conjunctiva has not been mirrored in the West, although SCC of the conjunctiva has certainly been seen28 and may be the presenting sign in AIDS.29

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