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Facts about Ovarian Cancer
The exact cause of ovarian
cancer is unknown. Ovarian cancer represents the 9th most common cancer
diagnosed in Australian women, but the 6th most common cause of cancer deaths
in this group1. The symptoms of ovarian cancer are often vague and
non-specific and can be confused with common symptoms of other disorders.
Often, by the time the cancer is diagnosed, the tumour may have spread beyond
the ovaries and into the uterus, bladder, bowel, and omentum. These cells can
begin forming new tumour growths before cancer is even suspected.
In Australia, 1 in 77 women will
be diagnosed with ovarian cancer before the age of 851. Similarly,
in the United States, the lifetime risk for a woman developing ovarian cancer
is 1 in 71, while the lifetime risk of death is 1 in 952. More than
half of the deaths from ovarian cancer occur in women between 55 and 74 years
of age. Approximately one quarter of ovarian cancer deaths occur in women
between 35 and 54 years of age.
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Stage 1

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Stage 2

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Stage 3

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Stage 4

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(From:
www.medscape.com)
Background
and Literature Review
Epithelial ovarian cancer is a
major cause of cancer mortality in women. The cancer is usually asymptomatic in
early stage and thus is often first diagnosed at late stage. Despite advances
in surgery, chemotherapy and radiotherapy techniques over the last few decades,
epidemiological studies indicate these advances have had a marginal impact on
the course of ovarian cancer. It is universally agreed that current therapy is
inadequate because of the advanced stage at which most ovarian cancer cases
present clinically. The vast majority of patients present with Stage 3/4
disease and have an extremely poor prognosis (~15-20% survive 5 years). Those
patients who present with properly staged, well-differentiated Stage 1 disease
have much better rates of survival (>90%). The development of an effective
community-based screening programme for early detection of ovarian cancer,
especially in high-risk women, is undoubtedly the number one priority for
long-term reduction of the mortality due to ovarian cancer.
While no ovarian cancer test has
been developed that is suitable for community-based screening, evidence
supports the hypothesis that certain epithelial ovarian cancers may be
detectable up to two years prior to their clinical presentation3,4.
Should it become possible to screen for Stage 1 disease with an accuracy of 80%
an overall ovarian cancer death reduction of the order of 50% should be
achieved.
Contemporary screening
approaches have focused on plasma/serum biomarkers (including the current gold
standard CA125 for monitoring disease treatment) and imaging techniques.
While a significant
proportion of asymptomatic ovarian cancers can be identified by measurement of
plasma CA1255, by real time ultrasonography6 and by
colour-flow Doppler7, these screening modalities, even when applied in combination, have an unacceptably low
positive predictive value and to date no effective population-based screening
strategy for ovarian cancer exists. Some further advantages have been suggested
by more recent studies employing annual CA125 screening with transvaginal
ultrasound as a second line test although it will still be several years until
definitive data on the effects of this screen on mortality can be determined.
1. National Breast and Ovarian
Cancer Centre, http://nbocc.org.au
2. Ovarian Cancer National Alliance, http://www.ovariancancer.org/
3. Jacobs I J; Rivera H; Oram D H; Bast R C, Differential diagnosis of ovarian
cancer with tumour markers CA 125, CA 15-3 and TAG 72.3., British journal of
obstetrics and gynaecology 1993;100(12):1120-4.
4. Jacobs I J; Skates S; Davies A P; Woolas R P; Jeyerajah A; Weidemann P;
Sibley K; Oram D H, Risk of diagnosis of ovarian cancer after raised serum CA
125 concentration: a prospective cohort study,.BMJ (Clinical research ed.)
1996;313(7069):1355-8.
5. Skates S J; Xu F J; Yu Y H; Sjövall K; Einhorn N; Chang Y; Bast R C; Knapp R
C, Toward an optimal algorithm for ovarian cancer screening with longitudinal
tumor markers. Cancer 1995;76(10 Suppl):2004-10.
6. Karlan B Y; Platt L D, Ovarian cancer screening. The role of ultrasound in
early detection. Cancer 1995;76(10 Suppl):2011-5.
7. Bourne T; Campbell S; Steer C; Whitehead M I; Collins W P, Transvaginal
colour flow imaging: a possible new screening technique for ovarian cancer. BMJ
(Clinical research ed.) 1989;299(6712):1367-70.
8. Menon et al (2009) Sensitivity and specificity of multimodal and ultrasound
screening for ovarian cancer, and stage distribution of detected cancers:
results of the prevalence screen of the UK Collaborative Trial of Ovarian
Cancer Screening (UKCTOCS), The Lancet Oncology 10(4): 327-40.
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