Risk factors

Question 1

Risk factors for ovarian cancer

Answer 1

- Increases the risk:
 Asbestos
HRT (oestrogen-only)
Tobacco smoking
- May increase the risk:
Talc-based body powder (perineal use)
X-radiation, gamma radiation
Adult-attained height
- Decreases the risk:
Oral contraceptives  25-28% lower in women who have ever used OCs compared with never-users; Risk reduces further with longer duration of OC use; it is more than halved with 10+ years' use
- May decrease the risk:
Breastfeeding (24% decresed risk)
Non-starchy vegetables (not salted or pickled)

Question 2

Ovarian Cancer and HRT

Answer 2

• Current use of HRT is a cause of ovarian cancer An estimated 1% of ovarian cancer cases in the UK are linked to HRT use.
• Ovarian cancer risk is 53% higher in long-term (5+ years) current oestrogen-only HRT users, compared with never users, a cohort study showed.
• Ovarian cancer risk is 17% higher in long-term (5+ years) oestrogen-progesterone HRT users, compared with never users.

Question 3

Ovarian cancer and smoking

Answer 3

• An estimated 3% of ovarian cancer cases in the UK are linked to smoking tobacco.
• Ovarian mucinous cancer risk is 31-49% higher in current smokers compared with never-smokers
• Risk increases with smoking duration.
• Ovarian mucinous borderline malignant tumour risk is 83-125% higher in current versus never-smokers.
• Ovarian clear cell and ovarian endometrioid cancer risk may be lower in current versus never-smokers.
• Other ovarian cancer types are not associated smoking.

Question 4

Ovarian Cancer and family history

Answer 4

• Around 3% of ovarian cancer cases occur in women with a family history of ovarian cancer.
• Ovarian cancer risk is 2.7-3.5 times higher in women whose mother or sister has/had ovarian cancer.
• Risk may be higher if the affected relative was diagnosed at a younger age.
• Ovarian cancer risk is higher in women whose sibling has/had stomach, liver, breast, prostate, or connective tissue cancer, or melanoma; or whose parent has/had breast or liver cancer
• Ovarian cancer risk is higher in families with a history of breast cancer compared with the general population, even when when BRCA1 or BRCA2 Open a glossary item mutations are not present.

Question 5

Ovarian cancer and BRCA genes

Answer 5

• Inherited conditions account for 5-15% of ovarian cancer cases
• Ovarian cancer risk is up to 65% higher in women with BRCA1 mutation, and up to 35% higher in women with BRCA2 mutation.
• Ovarian cancer risk among BRCA1 mutation carriers is lower in those who have given birth to 4+ children, those who have used oral contraceptives for a year or more, and those who have had tubal ligation.
• Ovarian cancer risk among BRCA2 mutation carriers is lower in oral contraceptives users but is not associated with reproductive factors or HRT use.

Question 6

Ovarian cancer and Lynch syndrome

Answer 6

• Around 7% of women with Lynch syndrome develop ovarian cancer by age 70.
• Around 21% of women with Peutz-Jeghers syndrome develop ovarian cancer aged 15-64.

Question 7

Ovarian cancer and endometriosis

Answer 7

• Ovarian cancer risk is 27-80% higher in women with endometriosis
• The association may differ by tumour type.

Question 8

Ovarian cancer and diabetes

Answer 8

• Ovarian cancer risk is 20-55% higher in diabetics

Question 9

Ovarian cancer and breast cancer

Answer 9

• Ovarian cancer risk is 24% higher in breast cancer survivors
• Ovarian cancer risk among breast cancer survivors is higher in those diagnosed with breast cancer at a younger age versus those diagnosed older, and higher risk is limited to oestrogen-receptor (ER)-negative or ER-unknown breast cancer