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Cervical cancer is a
malignancy of the cervix.
Worldwide,
cervical cancer is
the second most common cancer of women.
Cervical cancer
may present with vaginal bleeding but
symptoms of cervical cancer may be absent until the
cancer is
in advanced stages, which has made cervical
cancer the focus of intense screening
efforts utilizing the Pap smear.
Signs
and Symptoms of Cervical Cancer
The early stages of
cervical cancer symptoms may be completely
asymptomatic (Canavan & Doshi, 2000).
Vaginal bleeding, contact bleeding or
(rarely) a vaginal mass may indicate the
presence of malignancy. In advanced
cervical cancer,
metastasis may be present in the abdomen,
lungs or elsewhere.
Early Signs of
Cervical Cancer
The
possibility to identify premalignant changes on a
cervical smear has made screening the major cause
for referral of women with possible cervical
neoplasia. In many countries, women are advised to
have a regular Pap smear to check for premalignant
changes. Recommendations for how often a Pap smear
should be done vary from once a year to once every
five years. If cervical cancer is detected early, it
can be treated without impairing fertility.
Consistently abnormal smears may be a reason for
further diagnosis despite complete absence of
symptoms.
Diagnosis of Cervical Cancer
Diagnosis of cervical
cancer is made by doing a biopsy of
the cervix, which often involves colposcopy,
or a magnified visual inspection of the
cervix aided by using an acetic acid
solution to produce color changes in
precancerous or cancerous areas.
A Pap smear
is insufficient for the diagnosis of
cervical cancer. Many
researchers recommend that since more than
99% of invasive cervical cancers
worldwide
contain human papillomavirus, HPV testing
should be carried out together with routine
cervical screening (Walboomers et al, 1999).
Further diagnostic procedures
for cervical cancer are loop
electrical excision procedure (LEEP) and
conisation, in which the inner lining of the
cervix is removed to be examined
pathologically. These are carried out if the
biopsy confirms severe dysplasia.
Staging of
Cervical
Cancer
Cervical cancer is staged by the FIGO
staging system, which is based on clinical
examination, rather than surgical findings.
It allows only the following diagnostic
tests to be used in determining the stage:
palpation, inspection, colposcopy,
endocervical curettage, hysteroscopy,
cystoscopy, proctoscopy, intravenous
urography, and X-ray examination of the
lungs and skeleton, and cervical conization.
The TNM staging system for
cervical
cancer is analagous to the FIGO stage.
- Stage 0 -
full-thickness involvement of the
epithelium without invasion into the
stroma (carcinoma in situ)
- Stage I - limited to
the uterus
- IA - diagnosed only by
microscopy; no visible lesions
- IA1 - stromal invasion
less than 3 mm in depth and 7 mm or less
in horizontal spread
- IA2 - stromal invasion
between 3 and 5 mm with horizonal spread
of 7 mm or less
- IB - visible lesion or
a microscopic lesion with more than 5 mm
of depth or horizonal spread of more than
7 mm
- IB1 - visible lesion 4
cm or less in greatest dimension
- IB2 - visible lesion
more than 4 cm
- Stage II - invades
beyond uterus
- IIA - without
parametrial invasion
- IIB - with parametrial
invasion
- Stage III - extends to
pelvic wall or lower 1/3 of the vagina
- IIIA - involves lower
1/3 of vagina
- IIIB - extends to
pelvic wall and/or causes hydronephrosis
or non-functioning kidney
- IVA - invades mucosa of
bladder or rectum and/or extends beyond
true pelvis
- IVB - distant
metastasis
Note that the FIGO stage
does not incorporate
lymph node involvement
in contrast to the TNM staging for most
other cancers.
For cases treated
surgically, information obtained from the
pathologist can be used in assigning a
separate pathologic stage but is not to
replace the original clinical stage.
For premalignant
dysplastic changes, the CIN (cervical
intraepithelial neoplasia) grading is used.
Pathophysiology of Cervical Cancer
The American Cancer
Society provides the following list of risk
factors for cervical cancer: human papillomavirus infection, smoking,
HIV
infection, chlamydia infection, dietary
factors, oral contraceptives, multiple
pregnancies, low socioeconomic status, use
of the hormonal drug diethylstilbestrol
(DES) and a family history of cervical
cancer.
The presence of strains
16, 18 and 31 of human papillomavirus (HPV)
is the prime risk factor for cervical
cancer, and Walboomers et al. (1999)
reported that the presence of HPV is a
necessary condition for the development of
cervical cancer.
A virus cancer link with HPV has been found to trigger alterations in
the cells of the cervix, leading to the
development of cancer. The E6 gene
introduced by the virus inhibits the p53
gene, the central cellular switch for
apoptosis (the process by which damaged
cells kill themselves). The mitosis rate
accelerates, and the cell accumulates more
DNA damage that makes it capable of invading
other tissues.
Genital warts are caused
by different HPV types, and are not related
to cervical cancer.
The medically accepted
paradigm is that HPV can be considered a
sexually transmitted disease and that use of
condoms could prevent transmission. It is
thought to grow preferentially in the
epithelium of the glans penis, and
scrupulous washing and cleaning of this area
may be preventative. The position
on circumcision is controversial: some
researchers argue that routine neonatal
circumcision is an acceptable way of
preventing various diseases (which include
cervical carcinoma); others maintain that
the benefits do not outweigh the risks.
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