Familial cancer syndromes

Question 1

What is BRCA1 and 2?

Answer 1

autosomal dominant inherited tumor suppressor gene
incr risk breast, ovarian fallopian tube and peritoneal cancer
- tumor suppressor genes that encode proteins on DNA repair
- need genetic testing, increased surveillance and risk-reducing surgery and/or chemoprophylaxis

gyn cancers usually advanced high grade serous cancers.

Question 2

What is breast cancer surveillance in BRCA positive patients?

Answer 2

• age 25-29: breast exam q6-12 mo and annual MRI w/ contrast
• age 30+: annual mammogram and MRI, alternating q6mo. annual breast exam.

BRCA2 more associated with hormonal + breast cancer.

Question 3

What is ovarian cancer surveillance in BRCA positive patients?

Answer 3

TVUS or CA-125 at age 30-35 until undergo risk-reducing procedure.

Question 4

What is chemoprophylaxis in BRCA+?

Answer 4

Combined hormonal contraception (OCPs) decrease ovarian cancer risk.

Tamoxifen decreases breast cancer risk in BRCA2.

Question 5

When do you do risk-reducing BSO?

Answer 5

BRCA1: age 35-40
BRCA2: age 40-45
- need visual inspection of peritoneal cavity and washings. remove all ovarian and fallopian tube tissue
- ligate ovarian vessels 2cm proximal to end of identifiable tissue. If no hyst, fallopian tube divided at insertion to cornua.
- remove ovary at utero-ovarian ligament as close to uterus as possible.

After risk-reducing BSO, if NO breast cancer, can offer HRT to mitigate menopause effects.

Question 6

What is Lynch syndrome (HNPCC)?
What are lifetime risks of colon, endometrial and ovarian cancers?

Answer 6

AD, defects in mismatch repair system (multiple mutations)
- genetic testing available.
Possible cancers: colon, endometrial, ovarian, gastric, small bowel, renal, ureter, skin.

LIFETIME RISKS:
- colon cancer: risk 75%
- endometrial cancer: 40% (vs 2-3% in general population
- ovarian cancer: 15%

Question 7

What are screening recommendations for Lynch syndrome?
What is chemoprevention?

Answer 7

• Colon cancer screening: colonoscopy q1-2 yrs at age 20-25 or 2-5 years before earliest cancer diagnosis in family, whichever earlier.
• Endometrial cancer: EMB q1-2 yrs at 30-35. monitor signs of AUB.
• Ovarian cancer: TVUS/Ca-125 not effective (different biology than BRCA). if do screen, do 5-10 yrs before earliest diagnosis. continue until TAH/BSO.
• Breast cancer: normal screening recommendations.

Chemoprevention: 500mg ASAx2yr to decrease risk colorectal cancer
- progestin based contraception (including OCPs) for endometrial cancer.

• risk reducing hyst/bso in early to mid 40s.

Question 8

What is the risk of ovarian cancer w/ Lynch syndrome?

Answer 8

15%
1.8% in general population