Find out which factors increase a woman’s risk of ovarian cancer from the Singapore General Hospital (SGH) Department of Obstetrics & Gynaecology.
Ovarian cancer refers to a malignant growth, which arises from different parts of the ovary. Although it usually occurs in postmenopausal women over the age of 50, it can be diagnosed at a younger age, sometimes even during infancy.
How common is ovarian cancer in Singaporean women?
“Ovarian cancer is usually termed ‘a silent killer’ because it presents few, if any, symptoms,” says
Dr Ravichandran Nadarajah,Consultant,
Department of Obstetrics & Gynaecology,
Singapore General Hospital (SGH), a member of the
SingHealth group, of the disease that is the fifth most common cancer in Singapore affecting over 1,719 women.
According to the Singapore Cancer Registry Interim Annual Report 'Trends in Cancer Incidence 2010-2014’, ovarian cancer is the fourth most common cancer among Indian women, while it is the fifth most common among Chinese and Malay women.
It is the second most common female genital tract cancer, just after uterine cancer. There are over 344 new cases of ovarian cancer diagnosed yearly – majority of the ovarian cancer cases were stages 1 and 3, and in women aged 54 or lower.
Risk factors of ovarian cancer
You are at a higher risk of ovarian cancer if you can tick off one or more of the following factors:
This is considered the greatest risk factor of ovarian cancer. Positive history in one relative raises lifetime risk (the probability of developing or dying from cancer during one’s lifespan) to 5 per cent, while positive history in two relatives raises lifetime risk to 7 per cent.
Associated genetic syndromes
- Lifetime risk of ovarian cancer in those with who carry hereditary non-polyposis colorectal cancer syndrome (or HNPCC, which is a type of inherited cancer of the digestive tract) is 12 per cent.
- Hereditary breast and ovarian cancer syndrome increases the risk of breast, ovarian, pancreatic, and prostate cancers, and is associated with a 23 per cent to 54 per cent lifetime risk of ovarian cancer. Overall, hereditary breast and ovarian cancer syndrome accounts for 12 per cent of ovarian cancers.
Inherited gene mutations (of the BRCA1 or BRCA2, which are breast cancer genes 1 and 2) increase the lifetime risk of ovarian cancer to between 10 per cent and 26 per cent.
Other risk factors associated with ovarian cancer
|Increased risk||Decreased risk|
|Early menarche (start of menstruation)||Late menarche|
|Late menopause||Early menopause|
|Low parity (no. of times a woman has carried pregnancies to a viable gestational age)||Multiparity (risk decreases with each pregnancy)|
|Estrogen replacement therapy for more than 5 years||Oral contraceptive use|
|High-fat diet||High-fat diet|
|Family history suggesting genetic predisposition||Tubal ligation*|
|Genetic syndromes||Tubal ligation*|
* Hysterectomy and ligation are likely associated with lower risk because of decreased utero-ovarian blood flow, which limits local exposure to hormonal or potentially carcinogenic factors.