Breast CancerEpidemiology & Factors Influencing The Risk factors

*Normal BreastTo understand breast cancer, it helps to have some basic

knowledge about the normal structure of the breast :

The female breast is made up mainly of lobules

(milk-producing glands), ducts (tiny tubes that

carry the milk from the lobules to the nipple),

and stroma (fatty tissue and connective tissue

surrounding the ducts and lobules, blood

vessels, and lymphatic vessels).

*Breast cancer

Breast cancer is a type of cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk.

The first noticeable symptom of breast cancer is typically a lump that feels different from the rest of the breast tissue.

More than 80% of breast cancer cases are discovered when the woman feels a lump. The earliest breast cancers are detected by a mammogram. Lumps found in lymph nodes located in the armpits can also indicate breast cancer.

*Types of breast cancers

There are several types of breast cancer,

but some of them are quite rare. In some

cases a single breast tumor can be a

combination of these

:-Ductal carcinoma in situDuctal carcinoma in situ . DCIS is the most common type of

non-invasive breast cancer. DCIS means that the cancer cells

are inside the ducts but have not spread through the walls of

the ducts into the surrounding breast tissue.

:Invasive (or infiltrating) ductal carcinoma

This is the most common type of breast cancer. (IDC)

starts in a milk duct of the breast, breaks through the

wall of the duct, and grows into the fatty tissue of the

breast.

-Invasive (or infiltrating) lobular carcinomaInvasive lobular carcinoma (ILC) starts in the milk-

producing glands (lobules). Like IDC,it can spread

(metastasize) to other parts of the body.

:Less common types of breast cancer

-Inflammatory breast cancer: This uncommon type of invasive breast cancer

accounts for about 1% to 3% of all breast cancers.

Usually there is no single lump or tumor. Instead,

inflammatory breast cancer (IBC) makes the skin on

the breast look red and feel warm.

type -Paget disease of the nipple:

This of breast cancer starts in the breast ducts

and spreads to the skin of the nipple and then

to the areola, the dark circle around the

nipple. It is rare, accounting for only about

1% of all cases of breast cancer.

:Epidemiology of Breast Cancer

Breast cancer is the second most prevalent cancer in

the world and the most common cancer among women.

Breast cancer still persists as an international health

burden despite advances in its early diagnosis,

treatment and also increased knowledge of its

established risk factors. Although North American and

Northern European countries have the highest rates of

breast cancer incidence, the incidence of this disease is

increasing in developing countries. Asia, the largest

continent in the world.

Numerous epidemiological studies on risk factors

of breast cancer have produced evidence on

international variations. Many studies in the

literature have reported that breast cancer is

related to the reproductive life of women; such as

early menarche, late menopause, nulliparity, late

age at first birth, diet, physical exercise and

hormone usage

The American Cancer Society's most recent

estimates for breast cancer in the United States

are for 2012:

•About 226,870 new cases of invasive breast

cancer will be diagnosed in women.

•About 63,300 new cases of carcinoma in situ

(CIS) will be diagnosed (CIS is noninvasive and

is the earliest form of breast cancer).

About 39,510 women will die

The chance that breast cancer will be responsible for a woman's death is about 1 in 36 (about 3%). Death rates from breast cancer have been declining since about 1990, with larger decreases in women younger than 50. These decreases are believed to be the result of earlier detection through screening and increased awareness, as well as improved treatment

RISK FACTORS OF THE BREAST CANCER

RISK FACTORS YOU CAN NOT CHANGE

FACTORS WITH CONTROVERSIAL,OR UNPROVEN EFFECT

LIFE-STYLE RELATED RISK FACTORS

ENVIROMENTAL FACTORS

Risk factors you can not

changeGender

Aging

Genetic risk factor

Family history of breast cancer

Personal history of breast cancer

Certain benign breast conditions

Menstural periods

Gender

• Simply being a woman , is the main risk factor for developing breast cancer.

Aging

The older the women is , the more likely she is to get breast cancer.

• Why does age increase the risk of breast cancer?

Genetic risk factor

About 5% to 10% of breast cancer cases are thought to be hereditary.

• Inherited gene that may cause breast cancer include:BRCA1,BRCA2,tp53.

Family & Personal history of breast cancer

• Breast cancer risk is higher among women whose close blood relative have this disease.

• Less than 15% of women with breast cancer have a family member with this disease.

Certain benign breast conditions

Women diagnosed with certain benign breast conditions might have an increased risk of breast cancer.

certain benign breast conditions are divided into 3 groups, depending on how they affect this risk:

A)Non-proliferative lesions: These conditions are not associated with overgrowth of breast tissue.

B)Proliferative lesions without atypia:Theyseem to raise a woman's risk of breast cancer slightly (1½ to 2 times normal).

• C)Proliferative lesions with atypia: They have a stronger effect on breast cancer risk, raising it 3 1/2 to 5 times higher than normal.

Menstural periods

• Women who have had more menstrual cycles because they started menstruating early(before age 12) and/or went through menopause later (after age 55) have a slightly higher risk of breast cancer.

Factors with controversial ,or

unproven effect

Diet and vitamin intake

Antiperspirants

Abortion

Fertility drugs

Hair dyes

Trauma to the breast

Diet and vitamin intake

Most studies have found that breast cancer is less common in countries where the typical diet is low in total fat, low in polyunsaturated fat, and low in saturated fat.

Antiperspirants

• large study of breast cancer causes found no increase in breast cancer in women who used underarm antiperspirants and/or shaved their underarms.

Abortion

• Research clearly shows no link between abortion and breast cancer.

Fertility drugs

• Fertility drugs stimulate the ovaries, causing estrogen levels in the body to increase. Because high estrogen levels are linked to breast cancer risk, it has been suggested that the use of fertility drugs might also increase risk.

Hair dyes

Trauma to the breast

Life-style related risk factors

Giving birth(pregnancy)

Number of children(number of birth)

Breast feeding

Blood estrogen level

Alcohol

Weight gain and exercise

Giving birth(pregnancy)

• women who have had no children or who had their first child after age 30 have a slightly higher breast cancer risk.

-Why dose age matter?

There are a few possible reasons, One reason relates to breast cells. During pregnancy, breast cells grow rapidly .

Number of children(number of birth)

-In general, the more children a woman has given birth to, the lower her risk of breast cancer .

Breast feeding

• the longer a woman breast feeds, the greater the reduction in risk, with a 4.3% decrease in cancer for every 12 months of breast feeding.

Blood estrogen level

• estrogen is produced in a woman’s body (in the ovaries) and is essential for the development of the breast.

• paradoxically estrogen is also involved in the development of breast cancer via the stimulation and proliferation of breast cancer cells

Estrogen in pharmaceutical products The Pill and HRT

*Established risk factors for breast cancer - all of which increase a woman’s estrogen exposure:

• Starting periods early.

• Late onset of the menopause.

• Not having children or having them later in life.

• Not breastfeeding or breast feeding for only a short time.

• Use of oral contraceptives.

• Use of hormone replacement therapy.

• Obesity.

• Regular intake of alcohol

Alcohol

• Drinking alcohol has consistently been shown to increase breast cancer risk, in both pre- and post-menopausal women.

Weight gain and exercise

• Being overweight or obese after menopause increases breast cancer risk.

• Physical activity reduces a woman’s breast cancer risk, so regular exercise is advisable.

Environmental factors

• It is factors in our environment i.e. the world around us, that are thought to be responsible for at least some of the unexplained proportion (50%) of cases .

• Exposure to certain man-made chemicals that can mimic hormones.

• Our reliance on synthetic chemicals has increased dramatically over the last 50 years, and they are an integral part of our everyday 21st century lives, providing many lifestyle benefits.

Some chemicals found in our environment that have estrogen-

disrupting properties:

Several pesticides : DTT, some pyrethroidinsecticides , methoxychlor..

Polychlorinated biphenyls (PCBs)

• Used in capacitors and transformers, and some building materials.

• Marked under trade name arocol , pyranol,clophen.

Dioxins

• Are by-products which are not produced intentionally .

• PLASTICS have been identified as one of the most common causes of high levels of dioxins. in the tissues.

Bisphenol A (BPA)

- used in plastics and resins

to make water and food storage containers.

Parabens

- preservatives and antioxidants used in toiletries and cosmetics .

Alkylphenols

-nonyl phenol (NP) and octyl phenol (OP) – from plastics, paints, inks and detergents, and used in textile processing.

Conclusion

• Breast cancer is a disease of

premenopausal women as a whole, but

it's also affecting younger ages due to

underlying risk factors of life-style

changes and more exposure to man-

made chemicals that has became a

part of our daily life .The most cause of

the cancer may be due to risk factors

of age, family history, estrogen level

and environmental factors.