Breast cancer is cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas.
Prognosis and survival rate varies greatly depending on cancer type and staging. Computerized models are available to predict survival.  With best treatment and dependent on staging, 10-year disease-free survival varies from 98% to 10%. Treatment includes surgery, drugs (hormonal therapy and chemotherapy), and radiation.

Worldwide, breast cancer comprises 10.4% of all cancer incidence among women, making it the most common type of non-skin cancer in women and the fifth most common cause of cancer death.  In 2004, breast cancer caused 519,000 deaths worldwide (7% of cancer deaths; almost 1% of all deaths).  Breast cancer is about 100 times more common in women than in men, although males tend to have poorer outcomes due to delays in diagnosis.

Some breast cancers are sensitive to hormones such as estrogen and/or progesterone which makes it possible to treat them by blocking the effects of this hormones in the target tissues. These have better prognosis and require less aggressive treatment than hormone negative cancers.

Breast cancers without hormone receptors, or which have spread to the lymph nodes in the armpits, or which express certain genetic characteristics, are higher-risk, and are treated more aggressively. One standard regimen, popular in the U.S., is cyclophosphamide plus doxorubicin (Adriamycin), known as CA; these drugs damage DNA in the cancer, but also in fast-growing normal cells where they cause serious side effects.

Sometimes a taxane drug, such as docetaxel, is added, and the regime is then known as CAT; taxane attacks the microtubules in cancer cells. An equivalent treatment, popular in Europe, is cyclophosphamide,  methotrexate, and fluorouracil (CMF).  Monoclonal antibodies, such as trastuzumab  (Herceptin), are used for cancer cells that have the HER2 mutation.

Radiation is usually added to the surgical bed to control cancer cells that were missed by the surgery, which usually extends survival, although radiation exposure to the heart may cause damage and heart failure in the following years.

Causes of Breast Cancer

• You're over 50 There's nothing strange about this – cancers are caused by cell mutation, and the older you are, the more chance there is of a cell mutation occurring.

• Someone in your family has had breast cancer This slightly increases your risk. In most cases there's no family association. But scientists have identified certain genes that are responsible for some cases of breast cancer, and these can be transmitted to offspring. In these cases the cancer tends to occur at a younger age.

• The big ONo, not the late Roy Orbison, we're talking about the hormone oestrogen. High levels of oestrogen for long periods of time increase the likelihood of breast cancer. So do early puberty, late menopause, having your first child at a later age (over 35), not breast feeding, and never having children at all. The oral contraceptive pill is thought to increase the risk slightly, as does hormone replacement therapy (HRT) if taken for more than five years.

• Previous breast cancer Having had breast cancer in the past means you're three to four times more likely to get it again (not a recurrence, but an entirely new cancer somewhere else in either breast).

• Too much booze The link between alcohol consumption and breast cancer has been controversial, but the best available research suggests there is a link. Low levels of consumption – one standard drink a day or less – probably aren't a problem, but three drinks a day definitely increases your risk, maybe fewer if there are other risk factors. A standard drink is 10g alcohol, or about 100ml wine (a small glass).

• Smoking Again, research results have been mixed, partly because some studies take into account passive smoking while others don't. Those that do are more likely to find that exposure to tobacco smoke – passive or active – is a risk factor. Smoking is also an important risk factor for other cancers, including cervical and vulval cancers. There is NO evidence that underarm antiperspirants, underwire bras, or breast implants affect your risk of breast cancer.

Breast Cancer Symptoms

These signs don't necessarily mean cancer. But if any of these things happen to you, you should get it checked out.
In a rare type of breast cancer called inflammatory breast cancer, the whole breast can look red and inflamed and can be very sore. Another rare type of breast cancer shows up as a rash on and around the nipple. It is called Paget’s Disease. It looks a bit like eczema and is sometimes mistaken for that at first.

Breast Cancer Diagnosis

If you notice a breast lump you should see your GP. There is nothing to be gained from waiting; although some people do, often out of an unconscious (and ungrounded) fear that it's cancer. It's usually not, and if it is, the earlier you seek treatment, the better the chance of a cure.

Your GP will feel the lump in the breast and the lymph nodes under the arm, and do a general physical examination of the body. However, it's difficult to be 100 per cent sure whether a lump is benign just by clinical examination, so if there's any doubt, the GP will order further tests.

The simplest tests are imaging tests like mammography (a low-dose X-ray of the breast) and ultrasound (a picture formed by sound waves directed into the breast tissue).

If the lump looks and feels benign to the doctor and these imaging tests don't show anything suspicious, the GP may be content to keep an eye on the lump and ask the patient to come back in three months for a check-up.

If there's still doubt, the GP will usually refer the patient to a surgeon at this point. If the surgeon thinks the lump could be malignant, the next step is to do a breast biopsy. There are several different types:

• Fine needle biopsy Easiest to do and the least painful, this is performed in the surgeon's rooms or at a hospital outpatient clinic. The surgeon guides a needle into the lump and extracts a sample of cells (and/or from the fluid, if the lump is a fluid-filled cyst). These cells are then examined by a pathology laboratory and the result is usually available in one to three days.

• Core biopsy This is the same procedure, but uses a wide-gauge needle in order to extract breast tissue, not just cells, making it more accurate. It is done under local anaesthetic by a radiologist who uses an ultrasound to help guide the needle.

• Open biopsy A sample of breast tissue is taken from the lump via an incision into the breast under general anaesthetic.

If physical examination, imaging and biopsy all fail to show cancer, the condition is diagnosed as benign. This three-pronged approach is accurate in 99.95 per cent of cases.

Staging and treatment for Breast Cancer

In about one person in 20, the lump does turn out to be malignant.

Before treatment starts, breast cancers are 'staged' according to how advanced they are. Staging takes into account the size of the tumour, whether and where the cancer has spread, what the cells look like under the microscope, and what sort of breast tissue they've originated from.

Staging helps with prognosis (predicting how the disease will take its course) and also helps determine the most suitable treatment. Stage I or II signifies early breast cancer; Stage III or IV more advanced disease.

There are many treatment approaches, depending not just on the stage of the cancer but on the person's health, age and lifestyle. Treatment decisions involve not just a GP and a surgeon but a team of health professionals, and most importantly of all, the woman herself.

Almost all women – certainly those with early-stage breast cancer – will have some form of surgery recommended to remove the cancer. The chain of lymph nodes under the arm on the side of the affected breast is often also removed. In a new technique called sentinel node biopsy, the affected nodes can be biopsied and removed if cancer is found.

There are basically two options:

• Breast preservation treatment The surgeon removes the cancer, plus some tissue around it, leaving the rest of the breast intact – hence the name. It can also be called lumpectomy, wide excision, partial mastectomy, and quadrantectomy. Afterwards, the breast is always treated with radiotherapy. The treated breast will probably be slightly smaller and the nipple a little higher or lower than before.

• Mastectomy The entire breast, including the cancer, is removed. After surgery, the side of the chest that was operated on is flat and covered with skin with a scar across it. A prosthesis (an artificial breast worn in the bra) can be used if desired, or the breast can be surgically reconstructed using tissue from another part of the body like the abdomen, or a saline-filled bag.

Which is best? Well according to the experts, there's no difference between the two in terms of survival outcomes (though with breast conservation, there's a small chance of later recurrence of cancer in that breast, and it has to be removed by mastectomy). Most women prefer breast preservation treatment because it's less disfiguring. If the cancer is large or involves the nipple, however, breast preservation treatment may not be feasible, so it has to be mastectomy.

In many cases other than very early breast cancer, surgery is followed by a course of chemotherapy or hormone therapy lasting several months.
Regardless of which treatment is chosen, the process is often traumatic. So strong emotional support from partner, family and friends is important. Joining a patient group and using counselling services is also a good idea.