Overview
Cancer is a group of diseases that are characterized by abnormal cell growth in certain parts of the body. Based on the location they occur within the body and their type, there are over 100 types of cancers that affect humans. These cells have the potential to invade or spread to other parts of the body.
Breast cancer is cancer that develops from the breast tissue. About 5 – 10% of breast cancers are caused due to genetic reasons. Breast cancer usually develops in cells from the lining of milk ducts and the lobules that supply milk to the ducts. Based on where cancer develops from, there are two types of breast cancers – lobular carcinoma and ductal carcinoma.
- Lobular carcinoma – a type of cancer develops from the lobules.
- Ductal carcinoma – cancer developing from ducts is called ductal carcinoma.
- Besides these two, there are 18 other common types of breast cancer.
Breast cancer stands to be the most common invasive cancer in women, affecting about 12 % of women worldwide. About 22.9 % of all cancer cases are of breast cancer. The incidence of breast cancer is low in women aged less than 40 years, with only 5% of them being affected. This is because of the denser breast tissue.
In the developed countries, the survival rates for breast cancer are high, ranging between 80 – 90%. The survival rates are poor in developing countries.
In India, breast cancer is ranked number one cancer among women with an age-adjusted rate as 25.8 per 1 lakh women. Cervical cancer was earlier the most common cancer in Indian women, but breast cancer has taken over lately. Breast cancer is also the leading cause of death in women in India. In northeast India, breast cancer ranks top. By 2020, the number of breast cancer cases is likely to double in number.
Factors like betel quid, tobacco chewing, number of children, age at marriage, age at first childbirth, and age at menarche have proven to increase the risk of developing breast cancers. Longer menstruation periods due to late menopause are also associated with an increased risk of breast cancer.
Causes
The accurate causes of breast cancer are not known. However, significant factors like advancing age, family history of breast cancer and abnormal development of breast cells are considered to be some of the assumed causes. Normal breast cells could become cancerous due to the mutations in the DNA. Some of these mutations are inherited, but most are acquired during one’s life. Uncontrolled cell growth resulting from proto-oncogenes could also lead to cancer.
Certain benign breast lumps could also lead to breast cancers in women who had a history of breast or ovarian cancers. Women who have immediate family members with breast cancer are two to three times more likely to develop the disease. Genes known as BRCA1 and BRCA2 are identified as the two responsible genes causing breast cancer. Carrying one of these two genes could predispose women to breast cancer.
Exposure to the hormone estrogen increases a woman’s risk of developing breast cancer. This is because of estrogen’s ability to allow cell division and thereby increasing any abnormality, resulting in cancer. The levels of estrogen and progesterone vary all through the life of a woman based on her menstrual cycle, pregnancy and childbirth. Early menstruation, late first-pregnancy, shorter or longer menstrual cycle, etc. have been associated with the development of breast cancer. Studies show that hormone replacement therapy for menopause with combined estrogen and progestin could lead to the development of breast cancer. Radiation therapy could also be a causative factor of breast cancer.
Symptoms
A lump in the breast is the first noticeable symptom of breast cancer. As long as the tumor is small, it produces almost no symptoms. Painless lumps could be felt in the breast and at times, these lumps spread to underarm lymph nodes causing a visible swelling much before the lump in the breast could be felt.
Women could experience a change in the size, shape and appearance of the breast.
In some cases, symptoms like the following could be observed
- Dimpling of skin over the breast
- Redness of the skin over the breast
- Pitting of the skin over the breast (resembling the peel of an orange)
- Breast pain or heaviness
Some changes occurring with the nipple could be
- Spontaneous discharge from the nipple(sometimes, bloody discharge)
- Unexplained erosion or retraction
- Newly inverted nipple
- Rash on or around the nipple
One or more of the following changes could occur over the areola (the pigmented area of the breast, surrounding the nipple)
- Peeling
- Scaling
- Crusting
- Flaking
The breast carrying cancer could be larger and lower compared to the one that does not have cancer in it. Such varied features in the breasts of the same person could indicate the presence of breast cancer.
Pain (mastodynia) is a tool that cannot be considered reliable to indicate breast cancer as it could also be indicative of other breast health issues.
A type of breast cancer called the inflammatory breast cancer could pose diagnostic challenges as symptoms for this include itching, pain, swelling, nipple inversion, dimpling of the skin, redness of breast skin, etc. that resemble symptoms of breast inflammation. In this type of breast cancer, lumps are usually not seen, leading to a delay in the diagnosis of the disease.
Breast cancer could present as a metastatic disease (cancer spread beyond the original organ) in certain cases. Unexplained weight loss occasionally signals metastatic breast cancer. Bone or joint pains, jaundice or neurological symptoms could, at times, indicate metastatic breast cancer. However, these symptoms are considered as non-specific symptoms as they could be indicative of many other illnesses apart from breast cancer.
Not all lumps in the breasts are cancerous. It is seen that less than 20% of breast lumps turn out to be cancerous. Other breast disorders could be caused by benign breast diseases like mastitis and fibroadenoma. Though breast cancers are more likely to occur in aging individuals, the possibility of it occurring in younger individuals cannot be ruled out. Any sudden changes in the breast or appearance of new symptoms are to be carefully monitored for early detection of breast cancer is present.
Risk Factors
The risk factors for developing breast cancer can be divided into two categories
Modifiable risk factors
These risk factors include those that could be changed or altered by the individual. Factors such as consumption of alcoholic beverages, weight management, etc. could be considered as modifiable risk factors.
Fixed risk factors
Fixed risk factors include age, sex, genetics, etc.
- Sex – Greater risk of breast cancer is seen in women than in men.
- Age – As a person gets older, there is a subsequent increase in the chance of developing breast cancer.
- Habits – Consumption of alcohol and food with excess fat has been associated with breast cancer risk factors. Smoking tobacco has also been associated with increasing the risk of breast cancer.
- Genetics – The risk of breast cancer is greater in individuals whose relatives have or have had breast cancer. Having closer relatives or immediate family members with breast cancer elevates this risk even higher.
- Weight – Being overweight or obese increases the risk of breast cancer in women in both pre and post-menopausal stages.
- Disease history – Individuals who have had breast cancer earlier in life are likely to develop the disease again, either in the same breast or the other one. Apart from breast cancer, if an individual has had other breast conditions like a biopsy showing lobular carcinoma in situ (LCIS) or atypical hyperplasia of the breast, the risk of breast cancer increases. Those with diabetes mellitus are believed to have a greater risk of breast cancer.
- Menstruation – Women who started their menstrual cycle before the age of 12, and those who have not had menopause until 55 years of age, have an increased risk of breast cancer. Longer or shorter menstrual cycle than the average 26 – 29-day cycle also have an increased risk of developing the disease.
- Pregnancy – Women who have had their first child after age 30 are at a greater risk of breast cancer. Women who have never been pregnant also have a greater risk of breast cancer compared to those who have had one or more pregnancies. Multiple pregnancies are believed to suppress the risk of breast cancers in women. Few studies showed that induced abortions result in breast cancers.
- Breastfeeding – Not breastfeeding could make a woman vulnerable to breast cancer. Usually, breastfeeding for one to two years helps reduce the risk of breast cancer.
- Radiation therapy – Exposure to radiation therapy could increase the risk of developing breast cancer.
- Hormone therapy – Women who take hormone therapy for menopause with combined estrogen and progesterone have greater chances of developing breast cancer. Hormonal birth control pills have also been known to increase the risk of breast cancer.
- Medication – Women who have used oral contraceptives or birth control pills in the last ten years have an increased risk of breast cancer.
Diagnosis
Breast cancer can be diagnosed using the following procedures
- Breast examination: The breasts and lymph nodes in the armpits of an individual with a suspected cancer is examined by the doctor for any lumps or other abnormalities.
- Mammogram: An x-ray of the breast is called a mammogram. Mammograms are used for the screening of breast cancer. Once the screening mammogram detects the presence of a breast cancer, a further diagnostic mammogram will be recommended to evaluate the abnormality.
- Breast ultrasound: An ultrasound uses sound waves to produce images of structures deep inside the body. This could be used for the diagnosis of breast cancer to examine the lump formed inside the breast and helps understand whether the lump is a solid mass or a fluid-filled cyst.
- Biopsy: In this procedure, a sample is removed from breast cells and is tested. This is perhaps the most definitive way to diagnose breast cancer. For this to be done a doctor will use specialized needle device guided by an imaging test or an x-ray to extract a core of tissue from the suspicious area. These samples are sent to a laboratory for analysis to determine whether the cells are cancerous.
- A sample obtained from the biopsy is also used to determine the aggressiveness of cancer and to check whether the cancer cells have hormone receptors or other receptors which might play a role in the treatment procedures that are to be followed.
- MRI: A breast magnetic resonance imaging (MRI) is a machine that uses magnet and radio waves to create pictures of the interior of a breast. A dye will be injected into the area to be scanned before performing the procedure. An MRI scan does not use radiation to create images as the other imaging procedures do.
Treatment
Treatment of breast cancer depends on factors like the age of the patient, stage of cancer, etc. The intensity of treatment is dependent on the chances of disease recurring and patient prognosis. Surgery is the usual treatment option for breast cancer. This is followed by chemotherapy, radiation therapy or both, in most cases. To treat breast cancer, a multidisciplinary approach is preferred. Hormone-blocking therapy is used for cancers with the hormone receptors. Administration of monoclonal antibodies and immune-modulating treatments are done in case of metastatic breast cancers and other advanced stages of breast cancer.
Some of the most common options of treatment for the management of breast cancer include
- Surgery
- Medication
- Radiation
Surgery
- This is a widely-used treatment procedure which involves physical removal of the tumor. The tissue surrounding the tumor is also extracted during a surgery. Mastectomy, quadrantectomy, lumpectomy are the common surgeries used for breast cancer. Mastectomy involves removal of the whole breast. Quadrantectomy and lumpectomy involve removal of one-quarter of the breast and removal of a small part of the breast, respectively.
- After removal of the breast, a doctor may suggest a breast-reconstruction surgery, in order to improve the aesthetic appearance of the treated site.
Medication
- Drugs used for the treatment of breast cancer in addition to a surgery is termed as adjuvant therapy. Therapies done prior to surgery are termed as neoadjuvant therapy.
- Neoadjuvant therapy for breast cancer involves three main components – hormone-blocking therapy, chemotherapy and monoclonal antibodies.
- Hormone-blocking therapy – The presence of estrogen receptors (ER+) and progesterone receptors (PR+) on the surface of cancer indicates that cancer requires hormone to continue growing. These ER+ cancers are treated with drugs that block either the receptors (tamoxifen) or the production of estrogen with an aromatase inhibitor (anastrozole). These drugs, however, come with limitations. Tamoxifen could be used only for ten years and aromatase inhibitors are suitable only for women after menopause.
- Chemotherapy – This is used for the treatment of breast cancers between stages 2 – 4. Chemotherapy is effective in ER- patients. Usually, chemotherapy destroys fast-growing cancer cells by causing DNA damage. The medications used during the therapy also damage some fast-growing normal cells, which at times, could lead to serious adverse effects.
- Monoclonal antibodies – Monoclonal antibodies like trastuzumab improve the 5-year disease-free survival of stages 1 – 3 of HER2+ breast cancers to about 87%. The drug trastuzumab binds to the HER2 in the cancer cells of the breast and prevents growth factors from binding to the receptors and stimulating them, thereby blocking the growth of cancer cells effectively. This drug is however very expensive and could also pose some serious adverse effects.
Radiation
- This procedure is used after a surgery in order to destroy microscopic tumor cells that would have been left out after the surgery. This is said to have a beneficial effect on tumor microenvironment.
- Neoadjuvant therapy is said to decrease the recurrence risk of breast cancer by 50 – 66% when the delivery dose is accurate. This is even more useful in the lumpectomy.
Prevention
As discussed earlier, certain risk factors are modifiable while others are fixed risk factors. There is nothing one could do to help with the fixed risk factors but the individual has full control over the modifiable risk factors. The following precautions and lifestyle changes could help deal with the modifiable risk factors for breast cancer.
- Alcohol – Limiting the intake of alcohol or avoiding the consumption of alcohol could reduce the risk of developing breast cancer.
- Smoking – In premenopausal women, evidence suggests that not smoking can considerably lower breast cancer risk.
- Weight – Weight management is an effective tool, not just in the prevention of breast cancer but also in other health conditions prone to women. Being overweight after menopause increases the chances of breast cancer.
- Activity – At least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity is essential in preventing breast cancer. Strength training is also suggested twice a week to avoid breast cancer development.
- Breastfeeding – Breastfeeding plays a major role in the prevention of breast cancer. The longer a woman breastfeeds, the greater will be the protective effect. Studies show that breastfeeding for 1 – 2 years significantly lowers the chance of developing breast cancer.
- Therapy – Hormone replacement therapy for more than 3 – 5 years increases the risk of breast cancer potentially. Non-hormonal therapies are not harmful. If therapy is mandatory, the dosage could be adjusted to the lowest in order to reduce the potential risks that come along.
- Radiation – Medical-imaging procedures like computerized tomography (CT) scan uses high doses of radiation which could pose more harm for individuals with a risk of developing breast cancer. Such exposure is to be limited to only when absolutely necessary in order to avoid needless exposure.
FAQs
What are the risk factors for breast cancer in men?
Radiation exposure, BRCA 1/2 gene mutations, Klinefelter syndrome, testicular disorders, family history of breast or ovarian cancer, diabetes, gynecomastia (enlarged breasts), and obesity are the major risk factors of breast cancer in men.
Does breast cancer occur only in older women?
Though it is extremely rare for women under the age of 30 years to get breast cancer, the possibility is not ruled out. A large number of older women have been diagnosed with breast cancer, but it is also prevalent in those who are younger. 4% of Indian women diagnosed with breast cancer were aged between 20 – 30 years, 16% between 30 – 40 years and the rest 52% above 50 years.
What are the most common signs of breast cancer?
The signs of breast cancer may vary from person to person. Understanding one’s body and being familiar with one’s own personality helps in early detection of any abnormality observed in the breasts.
Common signs include
- Swelling of the whole/a part of the breast
- Skin irritation
- Dimpling of skin
- Breast or nipple pain
- Nipple retraction
- Redness and thickening of the skin on the breast
What are the chances of survival after having breast cancer?
For an average 5-year survival, it is up to 90%. The average 10-year survival rate is 83%. If cancer is located in just the breast and nowhere else in the body, the survival rate could be as high as 99%.
How are people with stage 4 breast cancer treated?
The treatment of stage 4 breast cancer is usually done with systemic therapy. This metastatic breast cancer treatment includes hormone therapy, chemotherapy, targeted therapy or these therapies in combinations.
Is stage 4 breast cancer dangerous?
As the stages of breast cancer advance, the tumor would be spreading beyond the breast and nearby lymph nodes to other parts of the body. The spreading of breast cancer is usually gone into bones, liver, lungs and sometimes even brain and other organs. Such spreading may turn to be dangerous and pose a potential risk to the individual.
