Breast cancer

Every year, around 5000 women in Austria are newly diagnosed with breast cancer (breast carcinoma). Taking into account the age distribution, this corresponds to around 76 cases of breast cancer per 100,000 inhabitants. In Germany, the German Cancer Aid estimates that there are around 69,000 new cases per year. This makes breast cancer one of the most common cancers in women, followed by bowel and lung cancer. Almost one in three cancers in the population as a whole affects the breast and around one in 13 women will develop breast cancer in her lifetime. The medical term breast cancer is derived from the Latin word "mamma" (breast, female mammary gland).

Since 1980, the annual number of new cases of breast cancer has roughly doubled. However, the mortality rate has been falling for decades thanks to improved diagnostics and early detection, new drugs and gentler surgical methods. Around 18,000 women die of breast cancer in Germany every year, yet around 87% of women are still alive after 5 years despite being diagnosed with breast cancer. Overall, this shows a significant improvement in the treatment of malignant breast tumors.

As with many other types of cancer, the actual causes of breast cancer are not known. However, there are a number of proven risk factors that can significantly increase the risk of developing breast cancer:

• Being overweight (obesity)

• Lack of exercise

• Diabetes (type 2 diabetes mellitus)

• Unhealthy diet (especially high in fat)

• Consumption of alcohol and nicotine

• Hormone replacement therapy during the menopause

• Dense breast tissue (lots of glandular and connective tissue in the breast)

• BRCA1 and BRCA2 mutations (some cases of breast and ovarian cancer in the family)

• Radiotherapy to the breast in childhood (e.g. for lymphoma)

Factors that reduce the risk of breast cancer are

• Higher number of pregnancies

• Duration of breastfeeding

• Young age at the time of pregnancy

• Late menstruation

• Early menopause

Female hormones: oestrogen and progesterone

The cells of the breast have hormone receptors (e.g. for oestrogen). This allows the body to influence breast tissue through substances circulating in the bloodstream (e.g. for breast growth). However, these oestrogens can also promote the development and proliferation of cancer cells. The so-called "hormone replacement therapy" - the continuation of the hormonal effect beyond the time of the natural onset of the menopause with medication - has been proven to increase the risk of breast cancer after a period of 5 years. Especially preparations with a combination of oestrogen and progestogens. If hormone therapy is discontinued, the risk returns to the average level within a few years.

Taking the contraceptive pill increases the risk of developing breast cancer, but does not increase the risk of dying from breast cancer. Oral contraceptives significantly reduce the risk of developing ovarian or endometrial cancer.

Unhealthy lifestyle

Current studies suggest that around a quarter of all breast cancers today could be prevented by a healthy lifestyle. Lifestyle factors that influence the risk of developing breast cancer are

• Healthy diet

• Normal weight (neither underweight nor overweight)

• Low alcohol consumption

• More physical activity

• Abstinence from smoking

Smoking is not only a risk factor for lung cancer, but also for breast cancer. Especially when girls start smoking as teenagers, their risk of breast cancer increases significantly. Animal fats should be avoided in the diet if possible. They increase oestrogen levels and thus lead to a higher incidence of breast cancer. This also explains the lower incidence of breast cancer in Asia, where traditionally less animal fat is eaten. However, the incidence of breast cancer is now also increasing significantly in Asian countries as a result of adaptation to Western cuisine. In general, a Mediterranean diet with a high proportion of fiber, fresh vegetables and fruit as well as more fresh sea fish is recommended to prevent breast cancer.

Inherited breast cancer

Around a third of all women with breast cancer have a hereditary predisposition. Mutations in the BRCA1 or BRCA2 genes can be detected in around 5 to 10 % of all breast cancer cases. Carriers of a BRCA mutation conversely have around a 70 % risk of developing breast cancer during their lifetime. They should therefore take part in an intensive early detection program for breast cancer. These programs usually include semi-annual breast examinations and regular magnetic resonance imaging (MRIs) from the age of 25. Some patients also decide to have their breasts removed as a precautionary measure, although such a procedure should only be carried out after a detailed consultation. A well-known example of this is the US actress Angelina Jolie.

Other known genes that can slightly increase the risk of breast cancer are

• ATM

• BRIP1

• CHEK2

• CDH1

• PALB2

• RAD51C and RAD51D

Around half of all breast tumors occur in women in the upper outer quadrant, with the left breast being affected more frequently than the right. Approximately 15% of breast carcinomas form in the inner outer quadrant.

At the beginning of the disease, breast cancer usually causes no symptoms. In advanced cases (with metastases), patients often experience symptoms such as weight loss, bone pain or breathing difficulties (dyspnoea).

Changes in the breast

Lumps in the breast are usually only palpable from a size of 1-2 cm. They cannot be moved, feel firm and usually do not hurt. The palpability of lumps also depends on their location (directly under the skin or deeper), the nature of the breast (lumpy or non-lumpy breast) and the size of the breast. Not every lump automatically means cancer, but every palpable change should be investigated further. Sometimes a cyst or compacted connective tissue can also be the reason for a palpable lump.

New retractions or depressions of the entire nipple, such as liquid secretions (bloody or non-bloody) - especially on one side - are an alarm signal that should be clarified by a doctor. In most women, the two breasts are of different sizes. However, if the change in size is new, those affected should see a doctor. It should also be clarified whether the breasts behave differently when the arms are raised. Skin abnormalities such as large pores ("orange peel skin"), redness and inflammation of the breast that does not subside and swelling in the armpit area can also be a warning sign of breast cancer and should therefore always be checked by a doctor.

Mammography is currently the gold standard for examining and diagnosing changes in the breast. It is currently used for early detection, but also for diagnosis and clarification of symptoms.

For women between the ages of 50 and 69, Germany has a statutory screening program in which participating women undergo a mammogram every two years. Outside of this target group - women without breast symptoms - screening is currently not considered useful. Women with a high hereditary predisposition to breast cancer (e.g. BRCA mutation) are excluded.

The mammogram

During a mammogram, each breast is briefly clamped between two Plexiglas plates and two images are taken (from top to bottom, from inside to outside). The examination itself only takes a few minutes. Afterwards, two radiologists usually assess the findings independently of each other. This is to ensure that even small changes are detected. If the mammography findings are unclear or a malignant neoplasm is suspected, the patient is usually invited for a second examination. The affected breast is then either examined using ultrasound (sonography) or a small tissue sample (biopsy) of the suspected change is taken. Of 30 abnormal findings in the mammogram, on average only around 6 turn out to be breast cancer. The remaining findings are false-positive.

Breast cancer treatment is usually multimodal. It usually consists of drug therapy, radiotherapy and surgery.

If breast cancer is detected early and treated according to the latest medical standards, most cases of breast cancer can be cured. Five years after a breast cancer diagnosis, around 87% of those affected are still alive. However, with many breast cancers, local recurrences or metastases must be expected even after a longer period of time, which often makes long-term treatment necessary.

In any case, complete destruction of the tumor is necessary (e.g. through chemotherapy or surgery) in order to cure breast cancer permanently. This is best achieved with a small tumor and if the tumor has not yet formed metastases in the body. Even despite treatment, breast cancer forms metastases in around 20% of patients. In around 7 % of patients, these tumors are already present at the time of initial diagnosis. If metastases are present, a complete cure - i.e. the complete removal of all tumor cells from the body - is unfortunately not possible with the current treatment options.

Surgery

The aim of surgery is always to completely remove the tumor with a tumor-free resection margin (R0) of the surrounding tissue. Breast-conserving therapy (BET) with subsequent radiotherapy is on a par with complete removal of the breast in terms of overall survival. This form of therapy can therefore currently be offered to around 70% of patients.

Adjuvant radiotherapy

Post-operative radiotherapy is used to prevent local recurrences. After breast-conserving therapy (BET), adjuvant radiotherapy should always be carried out to prevent recurrences.

Adjuvant drug therapy

Micrometastases can be destroyed by adjuvant drug treatment using cytostatics or specific drugs against oestrogen and growth factors. This significantly increases patients' chances of recovery. Unfortunately, almost a third of patients still suffer a relapse of the disease (recurrence).

Treatment of advanced stages of the disease

Palliative therapy for patients with distant metastases should contribute to the long-term stabilization of physical and mental well-being. Cytostatic drugs or oestrogen receptor blockers are used for this purpose. In around 20 - 30 % of all breast cancer patients, distant metastases occur as part of the disease. These distant metastases prevent a complete cure of breast cancer according to the current state of medicine.

The prognosis for breast cancer depends primarily on the stage of the disease and whether the tumor has already spread throughout the body via the bloodstream or the lymphatic system.

The five-year survival rate for breast cancer is around 83 to 87%. This means that 83 to 87% of patients are still alive five years after their diagnosis. For women whose cancer was detected very early, the five-year survival rate is as high as 90%.

Other factors that influence the prognosis are the type of tumor, the hormone receptor status, the size and aggressiveness of the cancer cells and the age and condition of the patient. For this reason, treatment of breast cancer must always be individualized.

If a tumor recurs at the same site, it is referred to as a recurrence. This occurs in around five to ten % of patients within the first ten years after successful treatment. In around 50 to 70 % of all cases, this localized recurrence is operable.

The Austrian breast cancer screening program gives all women over the age of 40 low-threshold access to mammography. This means that all women in Austria between the ages of 40 and 70 can take part in a breast cancer screening program with mammography. In Germany, women between the ages of 30 and 49 and over the age of 70 are eligible for annual screening. Here, gynecologists scan the breast as well as the lymph nodes in the armpit area. They look at the shape, size and any hardening in the breast area. Doctors may also notice changes in the skin or a discharge of fluid from the nipple. Between the ages of 50 and 69, women in Germany can also take part in a separate mammography screening every two years.

Intensive early detection for women with a genetic predisposition

For women who have an increased risk of breast cancer (e.g. due to a BRCA mutation), regular examinations and an intensified screening program can be useful even at a young age. In Germany, for example, a more intensive screening program includes an ultrasound examination (sonography) every 6 months from the age of 25 in addition to a palpation examination. A magnetic resonance imaging (MRI) scan is also carried out annually, as this is more accurate and involves less radiation than conventional mammography. From the age of 40, mammography is also used for intensified screening.