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Q&A : 2. Breast Biology

Breast cancer types

What are the types of breast cancer?
In-situ breast cancer means that the tumor is completely self-contained; in other words, it hasn't spread beyond the tissue where it started. Some physicians don't even consider these in-situ tumors to be true cancers (therefore, some women with in-situ cancer may have been told that their tumor was benign). However, women who have had in-situ disease are at greatly increased risk of developing a second breast cancer.

The number of in-situ cancers being detected now is increasing greatly, possibly because of the use of mammography.

Invasive disease refers to a cancer that has spread to surrounding tissue or other areas of the body. This is a more serious type.

Is breast cancer always a lump?
While breast cancer usually presents as a lump in the breast or armpit, it can have other appearances. These include a discharge or bleeding from the nipple, a persistent rash on the surface of the breast or nipple, overall enlargement or swelling of the breast, or dimpling (puckering) of the breast tissue. Of course, just as all lumps are not cancerous, these other symptoms do not always indicate cancer. However, they should always prompt a careful examination by a skilled health care provider. Breast pain is not a typical symptom of early cancers, and usually has another cause.

What does "estrogen-induced" cancer mean?
The clearest example of an estrogen-induced cancer is cancer of the endometrium (the lining of the uterus). Continuous exposure of the endometrium to estrogen, in the absence of a second hormone called progesterone, greatly increases the risk of developing cancer. Before this was recognized, many of these cancers developed in women taking an early form of birth control pills (called sequential OCPs, which are no longer used) and in women taking high doses of estrogen for menopause symptoms. For unclear reasons, women who develop endometrial cancer while taking estrogen seem to do a little better than those whose cancer occurred spontaneously.

The direct role of estrogen in the development of breast cancer is a little less clear. Women who take estrogen replacement therapy may be at a slightly increased risk (this is still being argued), but this is nowhere near the extra risk seen for endometrial cancer.

Is pre-menopausal breast cancer more likely to be fatal than post-menopausal breast cancer?
Is pre-menopausal breast cancer a different kind of cancer than post-menopausal breast cancer? There is no evidence at this point that pre-menopausal disease is different in nature from post-menopausal disease. But, among all the different breast cancers, some are more aggressive than others. As with many other cancers, the likelihood of having an aggressive cancer is higher with cancers diagnosed at young ages as compared with those diagnosed at older ages. For example, there is evidence that ON AVERAGE tumor doubling size is significantly faster in breast cancer diagnosed before age 50 than in breast cancer diagnosed after age 50. Still, in both age groups, some breast cancers have a fairly benign course after initial treatment and others metastasize aggressively. There simply are better odds of having the less aggressive kind of breast cancer as one gets older.

Anatomy & Breast Cancer

Is there an area in the breast that breast cancer is more likely to occur?
Yes 50% of breast cancer is found in women's upper -outer breast quadrant.

Are there more ligaments in the lower breast?

Are there lymph nodes actually in the breast?

Not in the breast tissue itself. They're in the chest under the ribs in the center and also under the arms. But the breast does drain into these lymph nodes, especially under the arm.

Is breast cancer of the left breast more common than breast cancer of the right breast?

A study published by the NIH in 1996 examined 250,000 cases of breast cancer which were collected by the national registry that records cancer cases (called the Surveillance, Epidemiology, and End Results, or SEER, program) to address this question. The results confirmed data from some earlier studies that there is an overall five percent excess of left-sided disease in women. This excess occurs for all races and stages of disease. For invasive breast cancer, the excess increases with age. (There is no excess of left-sided breast cancer observed among men who have male breast cancer.) Although the left breast is slightly larger on average than the right breast, there is little evidence that breast size is associated with breast cancer risk. The reason for the left-sided excess among women remains unclear (73).


Does breast cancer ever hurt?
Some kinds of breast cancer can hurt but most do not.

Do you have any more information about painful breast cancer? When breast cancer hurts does it hurt all the time, or only when touched?
Breast cancer is a collection of over 50 diseases affecting the breast tissue in which cells divide without control or order. Because of this, there is no way to give one answer for all different kinds of breast cancer. If a woman is having persistent pain that is unusual for her she should seek the advice of her health care provider.

Metastasis and lump growth

If I did find a cancerous lump, how fast could it be expected to grow?
The growth rate is an individualized thing. It would depend on the type and stage of the breast cancer found. There are also other factors that may be associated with tumor growth rate (e.g., antioxidants). Although breast self-examination and clinical breast examination can sometimes pick up tumors missed on a mammogram, the minimum size of a tumor that can be detected on a mammogram is smaller than the minimum size of a tumor that can be detected by breast self-examination (i.e. if done regularly mammography usually detects tumors at an earlier stage of growth than breast self-examination does). Note that younger women have a higher risk of having fast-growing types of breast cancer than do older women.

Is it true that a lump large enough to feel has probably been there for at least two years?
No - some tumors grow very fast (months) and some are very slow (years). It is very hard to determine how long a tumor has been present and undetected.

Does breast cancer have a "typical" pattern of metastasis? Is there a certain progression that is typical in breast cancer metastasis (i.e. lymph to lung to liver to bone, etc.)?
The first metastasis is usually to a lymph node. However, breast cancer can spread or disseminate via the blood stream. Since cancerous cells can be carried by lymph fluid or blood, the metastases can show up anywhere. The most common metastases are liver, lung, or bone - not in an order or progression.

If a woman has breast cancer and later she is diagnosed with lung cancer, how can a doctor tell that the lung cancer is the same cancer that has spread to a new site? Does the cancer have a "fingerprint"?
The doctor would take a sample of the cancer in the lungs (a biopsy with a long needle) and get some cells. A pathologist looks at the cells under a microscope and can tell if the cells are breast cancer cells or lung cancer cells or from some other site (like liver cancer cells or bone cancer cells). By doing this the pathologist can tell whether the cancer in the lung is a new cancer that is unrelated to the breast cancer or whether the cancer in the lung is breast cancer that has spread (or metastasized) from the breast to the lung.

Do other cancers metastasize to the breast?

Cancers originating outside of the breast can metastasize to the breast, although this is a relatively uncommon occurrence. When this does happen, the cancer is still classified by its site of origin, and is not considered to be a breast cancer. Some of the cancers for which breast metastases have been reported include melanoma, prostate, leukemia, lymphoma, and retinoblastoma.

Atypical Hyperplasia

What is Atypical Hyperplasia of the Breast?
Atypical means "not ordinary" and Hyperplasia means "excessive growth of normal cells in the tissues of an organ". So in simplistic terms atypical hyperplasia of the breast means that there is an unnatural growth or proliferation of cells in the breast tissue. Most often this occurs in the milk ducts. The cluster of cells in the duct looks like a small tumor by mammography. Although atypical hyperplasia is not cancerous itself, it has been associated with a moderately increased risk of breast cancer. A doctor will most likely remove the cluster of cells or collect a sample of the cells and run tests to determine what might be causing this growth.

What percentage of cases of atypical hyperplasia go on to become breast cancer?
There is not a simple numerical answer to this question. First, atypical hyperplasia is a type of benign breast disease. There are two types of atypical hyperplasia: atypical ductal hyperplasia and atypical lobular hyperplasia. Furthermore, pathologists categorize atypical hyperplasia by varying degrees from minimal to well-developed. There are also other types of benign breast disease such as proliferative disease without atypia, nonproliferative disease, fibroadenoma and others which can influence the risk for breast cancer. Some studies suggest that women with atypical hyperplasia can have an elevated risk for breast cancer upwards of 1.5 -3 times higher than the average for her age (9-12).

Is atypical hyperplasia the same as calcifications? No. There are two types of calcification:
1. Microcalcifications - These calcium deposits appear as numerous very fine white specks with various shapes (rods, branches, teardrops) on a mammogram. A radiologist carefully studies the shape and size of the calcium deposits to determine if they require further study. Most often, microcalcifications have nothing to do with cancer. However, sometimes they can be related to an early breast cancer and need follow up by mammogram or biopsy.

2. Coarse calcifications - On mammogram, these calcium deposits appear as single large white dots, few in number, widely dispersed, and round. They are usually benign (not cancer).


What are breast cysts?
Cysts develop when the normal glands in the breast enlarge and become filled with fluid. They can vary in size from too small to easily feel, to an inch or more in diameter. Cysts can be quite tender, particularly if they are growing rapidly. Changes in size are often associated with the menstrual cycle. Some people think cysts are related to caffeine intake, but this has not been clearly proven.

Cysts are the most common cause of breast lumps in young women. They are not breast cancers, and usually do not need to be removed.

Is aspiration of a breast cyst a treatment or diagnostic procedure?
Aspiration of a breast cyst can be both a diagnostic and a therapeutic procedure. If a breast lump is felt that seems probably to be a cyst, aspiration is often attempted. If fluid is removed and the lump shrinks in size, then the diagnosis of a cyst is confirmed. If the fluid is straw-colored and clear, it usually is not sent for further study. It if is grossly bloody, then it may be sent to a lab to be examined for cancerous cells. However, this is not a very sensitive test, and many doctors will instead opt to have the lump removed (for biopsy).

A breast cyst that is causing pain or tenderness can be treated with aspiration to relieve symptoms of discomfort. The cyst can recur unless the whole cyst is removed; for most women this is not necessary, however.

Benign breast disease

What is benign breast disease?
Benign breast disease describes a variety of non-cancerous breast abnormalities. These include several types of breast lumps, or tumors, such as the breast cysts. Unlike breast cancers, benign tumors do not invade the surrounding breast tissue, and do not metastasize (spread to other parts of the body). Doctors often will remove these growths by doing a breast biopsy, in order to determine for sure whether they are benign or cancerous.

One type of benign breast disease, called atypical hyperplasia, increases the risk of developing breast cancer by between 4 and 10 times. This is almost the same risk that is seen in women who have had in-situ breast cancer. Other types of benign breast disease, except for cysts (which don't seem to be related to increased breast cancer risk) may increase risk by one and a half to two times.

Fibrocystic disease

What is fibrocystic disease? Does it increase the risk of developing breast cancer?
Fibrocystic breast disease is a term which refers to a variety of changes in the breast tissue resulting from abnormal responses to hormonal stimulation. It is a very common condition which can appear as early as adolescence, but seldom develops after menopause. Many scientists do not like the label fibrocystic breast disease, because it can include a number of conditions which look and behave quite differently. They prefer to use the categories of non-proliferative and proliferative breast disease.

Non-proliferative breast disease includes simple breast cysts as well as fibrosis. One study did find an increased incidence of breast cancer in women with breast cysts larger than 1 cm, but only if they also had a positive family history of breast cancer in a first degree relative. However, most experts agree that non-proliferative breast disease (including cysts and fibrous changes) is not associated with any increased risk for the development of breast cancer.

Proliferative benign breast disease doubles a woman's risk for breast cancer, while atypical proliferative disease increases her risk 5-fold.

Lipoma (Fatty Tumors)

What is a fatty tumor (or lipoma)?
Fatty tumors are very common. They are benign tumors made up of fat cells that can occur in many parts of the body. They are most commonly noticed as rather soft, painless lumps under the skin. They can range in size from smaller than a pea to larger than a grapefruit. They are not usually removed, except for cosmetic reasons or if they appear to be growing rapidly.

Calcium Deposits

What does calcification signify, and why do calcium deposits in the breast occur?
Calcifications can represent many different biologic processes. Certain types of very small calcifications, called "micro-calcifications" can be associated with cancer, while others are not.

Do calcifications in the breast increase risk for cancer?
This is a question that needs to be fully discussed with a woman's physician. There are many different types of breast calcifications, and only the persons directly involved in her care will be able to answer a woman's questions.

Breast Feeding
If a woman is breastfeeding while she's pregnant, does her estrogen level affect the baby's health?
No, we do not believe serum estrogen levels relate very well to estrogen levels in breast milk, unless the woman is taking exogenous estrogens. We are currently unaware of an effect on the breastfed baby or a medical contraindication related to breastfeeding while pregnant as long as the mother is relatively fit and healthy (e.g., good nutritional status, low fatigue). Breastfed babies may wean during pregnancy because the breast milk may change qualitatively (e.g., changes in volume, changes in "taste").

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