Cancers Associated with HIV/AIDS
The Financial Gazette
August 04, 2000
CANCERS associated with AIDS are not new diseases. They occur with
low frequency in the ordinary population. Their frequency has,
however, markedly increased in HIV/AIDS patients.
These
cancers are not only associated with HIV/AIDS but studies now show
that the natural history of these cancers is altered in HIV-infected
patients.
Patients
tend to present more advanced disease that is more rapidly
progressive and respond less well to therapy/treatment than in
HIV-negative people.
Cancers
develop in approximately 40 percent of AIDS patients. Cancers arise
from cells that have lost control of their division process. Of the
10 or so types of cancers associated with AIDS, the first three are
the most common and these will be discussed further in this article.
1.
Kaposi's sarcoma
2.
B-cell lymphoma
3.
Invasive cervical carcinoma
4.
Hodgkin's disease
5.
Carcinoma of the orophanynx
6.
Hepatocellular carcinoma
7.
Carcinoma of the lung
8.
Testicular tumor
9.
Melanoma
Kaposi's
sarcoma
Kaposi's
sarcoma (KS), once a rarely reported cancer worldwide before the HIV
epidemic, is the most commonly reported cancer affecting
HIV-infected individuals.
The
exact cause of KS is still unknown. Some studies have implicated a
sexually transmitted agent. Evidence continues to accumulate
implicating the Human Herpes Virus (HHV-8).
Others
have implicated certain chemicals found in the body while others
doubt whether KS is really a cancer because unlike other cancers
which arise from a single cell type, KS arises from several cell
types.
KS
lesions are made up of an overgrowth of blood vessels. The highest
prevalence in HIV patients occurs in homosexual men, followed by
heterosexual men and lastly women.
Moritz
Kaposi first described KS in the 1800s, prior to the AIDS epidemic,
as a cancer of muscle and skin. KS was relatively uncommon and three
forms of the disease were recognised.
-
Classic KS a chronic skin disease affecting the legs of elderly men
of Mediterranean, Eastern European or Jewish descent.
-
KS that occurred endemically in parts of Central Africa and consists
of benign nodular lesions.
-
Iatrogenic KS (that is, caused by medical treatment) occurring in a
wide spectrum of patients receiving immune suppressive agents for
organ transplants, etc.
A
fourth form of KS epidemic KS, which is AIDS-related was recognised
in 1981. The incidence of KS continues to rise in patients with HIV
infection. In AIDS patients KS is more virulent and progressive. The
exact cause of KS is not known.
Clinical
presentation
Lesions
of KS vary with the colour of the patient. They start off small,
painless and flat. They become enlarged, raised, pink to purplish
plagues on the skin and mucous surfaces, especially in the mouth.
Spread
occurs to the lungs, liver, spleen, lymph nodes, digestive tract and
other internal organs. In its advanced stage it may affect any area
from the skull to the feet. In the mouth, the hard palate is the
most common site of the KS but it may also occur on the gum line,
tongue and tonsils.
KS
does not usually cause death directly in HIV patients. However,
bulky cutaneous lesions may become painful and can restrict
movement. Lymphatic obstruction is common and can result in severe
edema of the legs and face.
Rare
cases of obstruction, perforation and GI bleeding have been
reported. Pulmonary KS results in cough and other respiratory
symptoms, including death from respiratory failure.
Finally,
KS can have enormous psychological problems due to disfiguring,
particularly swelling of the face and lower limbs. Diagnosis
Careful
examination of the skin and mouth at each clinic visit is the key to
early diagnosis. Once lesions are identified, a biopsy for
histological confirmation should be taken.
Therapy
for KS is palliative, particularly because most patients do not die
as a direct result of KS. Specific therapeutic goals include
cosmetic improvement, relief of local symptoms — for example pain
and edema — or relief of systemic complications of visceral KS.
Lymphoma
Lymphoma,
a cancer of lymphoid immune cells, is the second most common cancer
in HIV/AIDS and is now the seventh most common cause of death in
people with AIDS. It is common in patients with swollen lymph nodes.
Some cancers arise from T-cells of the immune system but the
majority 95 percent originates from B-cells (B-lymphocytes).
The
cause of lymphoma in patients with HIV is not know for sure but
scientists link it to the presence of both Epstein-Barr virus (EBV)
and Human herpes virus 8 (HHV8). This does not, however, exclude
other viruses as causative agents.
Clinical
presentation
The
commonest sites of cancer growth are the heart and rectal area but
particularly the brain, resulting in symptoms such as memory loss
and confusion, fits, lethargy, headache and weakness of one side of
the face. Lymphomas have however been reported in almost all other
parts of the body in HIV/AIDS patients.
Approximately
75 percent of patients with AIDS-related lymphomas also present
non-specific symptoms of unexplained fever, weight loss and
drenching night sweats.
Diagnosis
Procedures
that assist in the diagnosis of lymphomas are CT scan of the brain
and abdomen, surgical biopsy and needle aspiration of tissues and
fluids from suspected organs of the body. The diagnosis is then
reached when the typical histologic picture is detected on
examination of the specimen.
Treatment
of brain lymphoma is with radiotherapy. Cancers often respond but
survival is very poor beyond three months. Slight improvement has
been reported with combined radiotherapy and chemotherapy.
Disease
outside the brain is generally treated with chemotherapy, which
again gives limited success. In fact, chemotherapy has been found to
be detrimental to the immune system, resulting incidentally in
accelerated progression of the HIV disease. There was a progressive
decline in CD4 cell and a two-fold increase in opportunistic
infections during chemotherapy. Invasive cancer of the cervix
Cervical
intraepithelial neoplasia (CIN), also referred to as
cervical dysplasia, are pre-cancerous lesions that lead to cancer
of the cervix in females.
In
normal people, the progression of CIN to invasive cancer is a slow
process taking many years, affecting women between the ages of 45
and50 years. Treatment outcome in normal female patients is very
favourable once detected.
However
in HIV/AIDS female patients, CIN progresses more rapidly and occurs
early between the ages of 16 and 40 years. It is also less
responsive to treatment and has a poor prognosis (forecast). The
risk of developing cancer of the cervix is greatly increased by:
-
Early age at first sexual intercourse.
-
History of sexually transmitted diseases.
-
Multiple sexual partners.
-
Immuno suppression especially infection with Human papilloma virus (HPV).
-
Use of oral contraceptives.
-
Cigarette smoking.
-
Dietary deficiencies.
-
Low socio-economic status.
-
A lack of access to health care.
HPV
is detected in 95 percent of all cancers of the cervix. Cancer of
the cervix is considered a preventable disease; it is therefore
recommend that women with HIV infection have a Pap smear more
frequently than HIV-negative women.
Clinical
presentation
Vaginal
bleeding, especially during and after sexual intercourse, is the
most common symptom of cancer of the cervix. Other symptoms include
heavy bleeding, blood-stained discharge, abdominal pain, pelvic,
back and leg pain, anorexia, weight loss and anaemia.
A
complete diagnostic study should be performed by a gynaecologist.
Treatment depends on the stage of the disease and includes single or
combination strategies of radiotherapy and chemotherapy.
Summary
Patients
with HIV infection are at a higher risk of developing many cancers
such as Kaposis sarcoma (KS), lymphomas and invasive cervical
cancer. Many of the cancers that occur in HIV-infected patients have
a more aggressive course resulting in a shorter survival time.
©2000 The Financial
Gazette, All Rights Reserved.
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