Biology of Cancer

Biology 207 Fall 2005 Biology of Cancer

Lecture 29 "Breast Cancer"

Readings: King p. 278, Bazell (1998) Her-2

Outline: 1. Breast cancer statistics 2. Major types of breast cancer 3. Risk factors 4. Detection of breast cancer 5. Treatments

Lecture:

1. Breast cancer statistics

--1:8 chance of breast cancer for women in their lifetimes --Leading cause of cancer death in women aged 40-55 --Male breast cancer about 1% of cases

2. Major types of breast cancer

Breast--specialized gland that produces milk to nourish infants.

Glands--epithelia that secrete substances.

Anatomy--lobules=site of milk production --ducts=carry milk to nipple

80% of cases: invasive ductal carcinoma (IDC) 10-15% of cases: invasive lobular carcinoma (ILC)

3. Risk factors for breast cancer

--age --previous cancer in one breast --family history 5-10% of breast cancers BRCA1 BRCA2 p53 --benign breast disease (fibrocystic disease) cysts--fluid filled sacs fibrosis--scar tissue (connective tissue) formation --early menstruation

1 --late menopause --no children or birth of first child after age 30

Reduce risk by

--low fat diet --exercise? --stop smoking --limit alcohol --not taking the pill? --limited use of estrogen replacement therapy --avoid pesticides, environmental chemicals

Recommendations for women with family history of breast cancer --gene testing (and counseling)? --tamoxifen (anti-estrogen therapy) or raloxifen (trial) --prophylactic (preventative) mastectomy?

4. Detection of breast cancer --breast self exam (BSE), monthly after age 20 --clinical breast exam --mammogram after age 40, every 1-2 yrs --confirmation by mammogram, ultrasound, &/or biopsy

Breast cancer staging: TNM system, simplified to stages 0-IV

Stage 5 year survival rate

O 100% I 98% IIA 88% IIB 76% IIIA 56% IIIB 49% IV 16% metastatic breast cancer

5. Treatments --surgery (type depends on stage of cancer) lumpectomy partial mastectomy total mastectomy modified radical mastectomy radical mastectomy

--radiation therapy --hormone therapy (anti-estrogen therapy, such as tamoxifen)

2 --chemotherapy --rarely, bone marrow transplant --for Her-2/neu positive tumors, antibody therapy