Ovarian Cancer

Epidemiology of Cancers: Ovarian Cancer

Description
Ovarian tumours are classified according to their tissue of origin1.
Epithelial (90% of cases)
Sex cord stromal (6%)
Germ cell (3%)

Symptoms
Onset of symptoms is usually insidious, with most patients presenting at an advanced stage.
Symptoms inlude1:

Abdominal pain or discomfort
Abdominal swelling
Pelvic pressure such as urinary frequency.
Abdominal mass usually present on examination
Weight loss

Epidemiology

  • Worldwide and estimated 190,000 new cases of ovarian cancer are diagnosed each year.
  • The highest incidence rates occur in the United States and Northern Europe and the lowest rates in Africa and Asia.
  • Ovarian cancer is the fourth commonest cause of death from cancer amongst women in the UK.  The majority of women who develop this cancer have few symptoms until it has spread outside the ovaries.
  • In 2002 there were 6,959 cases of ovarian cancer diagnosed in the UK.
  • Ovarian cancer incidence increases with age. There is a marked increase in incidence among women after the age of menopause, with over 85% of cases diagnosed in women aged over 50 years2.
  • The highest incidence rates are for women aged over 70 years.
  • Ovarian cancer causes 4,600 deaths in the UK each year.
  • Five-year survival rates for all stages are only 25-30%.

Risk Factors

  • Age - incidence increases with increasing age
  • Family history
  • Nulliparity
  • Mutations in BRCA1, and BRCA2 and hereditary nonpolypous colorectal cancer (HNPCC) genes are associated with an increased risk of ovarian cancer, although only about 10% of ovarian carcinomas occur in those know to carry the recognised mutations2.

Potential protective factors

  • Oral contraceptive use
  • Parity
  • Breast feeding
  • Tubal ligation

Screening and Prevention
There is currently no national screening programme for ovarian cancer in the UK.

The UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) is currently being conducted in the UK. This large randomized control trial (of 200,00 post-menopausal women)  is aimed at assessing whether screening will detect ovarian cancer at an early stage when treatment is more effective and therefore reduce mortality.

The primary screening modalities being tested are:

Transvaginal ultrasound

CA125 testing - Most women who develop ovarian cancer have high levels of the protein CA125 in their blood. Elevated levels of CA125 have also been found among women in the early stages of many ovarian cancers.

References

  1. Adami, HO, Hunter D, Trichopoulos D, eds. Textbook of Cancer Epidemiology, Oxford University Press: New York, 2002.
     
  2. Cancer Research UK: http://info.cancerresearchuk.org:8000/cancerstats/

© CM Kirwan 2006