Invasive Breast Carcinoma

Invasive breast carcinoma is the most common type of breast cancer, affecting thousands of women each year. Understanding this condition, its symptoms, and treatment options can help patients and their families navigate the journey ahead with greater confidence.

Table of contents

• What is invasive breast carcinoma?
• Common types of invasive breast carcinoma
• Symptoms to watch for
• How is it diagnosed?
• Treatment options
• Understanding your outlook

What is invasive breast carcinoma?

Invasive breast carcinoma means that cancer cells have grown through the lining of the milk ducts or milk-producing glands and have spread into the surrounding breast tissue^[2]. This is different from conditions where cancer cells remain contained inside the ducts. When breast cancer is invasive, it has the potential to spread to other areas of the body through blood vessels and the lymphatic system^[9].

Invasive breast carcinoma is the most common type of breast cancer. Between 70 and 80 out of 100 breast cancers are this type^[2]. Most invasive breast cancers have no special features when examined under a microscope and are classified as No Special Type (NST) or not otherwise specified (NOS)^[2][3].

Although invasive breast cancer typically affects women age 55 and older, it can also occur in younger women and, rarely, in men^[10]. About 10 percent of women diagnosed with invasive breast cancer are under age 45^[8].

Common types of invasive breast carcinoma

There are two main types of invasive breast carcinoma, which together account for about 90 percent of all invasive breast cancers^[8].

Invasive ductal carcinoma (IDC) is the most common type, making up about 70 to 80 percent of all invasive breast cancers^[9][5]. With IDC, cancer cells start in the milk ducts, break through the walls, and invade breast tissue. It can remain near where the tumor started or spread anywhere in the body^[8]. This type was previously also known as invasive ductal carcinoma of the breast^[3].

Invasive lobular carcinoma (ILC) accounts for about 10 to 15 percent of invasive breast cancers^[9][5]. ILC starts in the lobules or milk glands and then spreads into nearby breast tissue. With ILC, most women feel a thickening instead of a distinct lump in their breast^[8]. This type is more likely to form in both breasts at the same time than other breast cancers^[5].

Some women may have a combination of both types or a different, less common type of invasive breast cancer^[8].

Symptoms to watch for

Breast cancer may have no noticeable symptoms, especially during the early stages. In fact, routine breast screening can often pick up cancer before you notice any symptoms^[3]. However, when symptoms do appear, they may include several warning signs.

Common symptoms of invasive breast carcinoma include a new lump or thickening in your breast or armpit that continues after your monthly menstrual cycle^[2][8]. This mass may feel as small as a pea^[8][10]. You might notice a change in the size, shape, or feel of your breast^[2][3].

Skin changes are another important sign to watch for. The skin on the breast may look puckered, dimpled, scaly, or inflamed and reddened^[2][8]. Some women describe a rash on the breast^[3]. An area that is distinctly different from any other area on either breast should be checked by a doctor^[8].

Changes to the nipple are also important symptoms. These include changes in the position of the nipple, the nipple turning inward, or fluid leaking from the nipple in a woman who isn’t pregnant or breastfeeding^[2][3]. You may also feel a marble-like hardened area under the skin^[8][10].

The symptoms listed here are more often caused by other medical conditions. But if you have any of them, it is important to see your doctor^[2].

How is it diagnosed?

If you have symptoms that could be due to invasive breast cancer, your doctor may refer you to a breast clinic^[2]. You may also be referred for tests if your screening mammogram shows an abnormal area^[2]. It’s important to know that most people who attend a breast clinic with symptoms do not have breast cancer^[2].

You will usually have a number of tests to check for breast cancer. A healthcare provider will perform a physical examination, checking for lumps in your breasts and swollen lymph nodes in your armpit^[10]. The lymph nodes are small, bean-shaped structures that filter fluid and help fight infection^[16].

Imaging tests play a key role in diagnosis. These may include a mammogram, which is an X-ray picture of the breast^[2], and a breast ultrasound scan, which uses sound waves to create images of breast tissue^[2][3]. Some patients may also need a breast MRI, which uses magnets and radio waves to create detailed pictures^[3].

The most important test is a biopsy, where a sample of tissue is taken from your breast using a needle^[2][3]. During the biopsy, doctors may use mammography or ultrasound images to guide the needle to the area of concern^[14]. A specialist called a pathologist will examine the tissue sample under a microscope to determine if cancer is present and what type it is^[14].

After a diagnosis of breast cancer, all tissue samples are tested to identify whether the cancer cells have receptors for estrogen, progesterone, or a protein called HER2^[15]. These receptors are protein molecules on cells’ surfaces that can attract certain substances in your blood, including hormones that help cancerous tumors grow^[10]. Knowing the receptor status helps doctors decide which treatment will be most effective^[2][10].

Treatment options

Your doctor will consider many different factors when deciding which treatment is best for you. This is why your treatment may be different from other people with invasive breast cancer^[2]. Factors include the type of cells the cancer started in, the size of the cancer and whether it has spread, how abnormal the cells look under the microscope, whether the cells have receptors for particular cancer drugs, your general health, and whether you have had menopause^[2][4].

Treatment for invasive breast cancer typically involves multiple approaches. Many patients will have treatment before surgery, during surgery, and after surgery^[2].

Drug treatments before surgery

You might have chemotherapy or hormone therapy before surgery. This is called neoadjuvant therapy^[2][15]. The main aim is to shrink the cancer before surgery, which may allow for a less extensive operation^[2]. Chemotherapy uses drugs to kill cancer cells, while hormone therapy blocks hormones from reaching breast tissue to prevent cancer growth^[14].

Surgery

There are two main surgical options for invasive breast cancer, and both have similar survival rates^[15]. Breast conserving surgery, also called lumpectomy, removes the cancer while leaving as much normal breast tissue as possible^[2][14]. This option is used when the tumor can be removed completely with good cosmetic results^[15]. After a lumpectomy, patients typically receive radiation therapy^[15].

A mastectomy is an operation to remove the whole breast^[2][14]. If you have a mastectomy, you might be able to have a new breast made, called breast reconstruction. This may be at the same time as the mastectomy or some time afterwards^[2].

You may also have surgery to remove lymph nodes in your armpit. When there is suspected disease in the lymph nodes, doctors perform a sentinel lymph node biopsy, which is preferred over removing all the lymph nodes^[15]. Your surgeon will let you know whether you need this^[2].

Treatments after surgery

After surgery, you may have other treatments. These include radiation therapy, which uses high-energy radiation to kill cancer cells^[2][14]. Additional chemotherapy may also be recommended^[2].

If your cancer has hormone receptors, you will likely receive hormone therapy after surgery^[2][15]. This treatment blocks estrogen or progesterone from reaching breast tissue^[14].

Targeted cancer drugs may be used if your cancer has certain characteristics. These drugs target specific features of cancer cells^[2]. For example, if your cancer makes high levels of the HER2 protein, you may receive drugs that specifically target HER2^[10].

Women who have gone through menopause should also be offered drugs called bisphosphonates after surgery. These drugs strengthen the bones^[2][15].

Understanding your outlook

Often, healthcare providers can cure invasive breast cancer if tests detect tumors before they spread to other areas of your body^[10]. Your own outlook depends on what type you have, how much and where your cancer has spread, and other individual factors^[8].

Healthcare providers base cancer stage on factors like the tumor’s location and size. Knowing the stage helps your care team plan the best treatment approach^[10]. Early-stage invasive breast cancers that have not spread beyond the breast and nearby lymph nodes are considered nonmetastatic^[4].

If breast cancer spreads beyond the breast to other parts of the body, it is called metastatic breast cancer^[5][16]. This is also called stage IV or advanced breast cancer^[5]. Metastatic breast cancer is treatable but not curable, and treatment goals include improving the length and quality of life^[15].

It’s important to remember that research continues to improve treatments and outcomes. Knowledge about your specific type of breast cancer empowers you and your healthcare team to make the best decisions for your care.

invasive ductal carcinoma, infiltrating ductal carcinoma, IDC, invasive ductal breast cancer, invasive ductal carcinoma of the breast, breast cancer not otherwise specified, NOS

• Breast tissue
• Milk ducts
• Lobules (milk glands)
• Lymph nodes