Ductal, lobular, and medullary neoplasms are three of the main types of breast cancer.
Unlike most cancers, they are differentiated according to location rather than the cell or tissue type. Each one develops differently and has a different prognosis and treatment.
The most common type is ductal cancer, which occurs in the lining of the milk ducts. This cancer occurs in two forms: ductal carcinoma in situ (DCIS), which is confined to the milk ducts; and infiltrating ductal carcinoma (IDC), which invades the surrounding tissue. Ductal cancers account for 70% of all cancer cases.
Lobular cancers occur in the lobules, the small sacs containing milk-producing glands. Like IDC, it can spread to surrounding tissue and eventually to other organs. Because the lobules are located deeper in the breast, lobular cancers are harder to detect in traditional mammograms.
Medullary cancers account for about 5% of cases. They are technically a type of IDC, but are differentiated because they resemble a part of the brain called the medulla. These cancers can be hard to detect in the early stages, but since they are slow-growing, they usually have a better prognosis than other invasive types.
Doctors have established a genetic link in about 5% of breast cancer cases, so a family history of cancer can put one at risk. Other common factors include:
- Age: About 80% of breast cancers affect women over 50.
- Obesity: Women who have a body mass index (BMI) over 30 are more likely to develop cancer. The risk is even greater if the excess weight was gained after menopause.
- Early menstruation/late menopause: Women who got their periods before age 12, or enter menopause after 55, are more at risk of developing breast cancer. This may be because the breasts are exposed to estrogen for a longer period.
- Late pregnancy: Breast cancer is more common in women who have their first full-term pregnancy after age 30. It isn’t clear why, but studies show that early pregnancies may prevent the genetic mutations caused by estrogen exposure.
- Radiation exposure: Women who have received radiation treatments to the chest, particularly when during breast development, are more likely to get breast cancer later on.
- Medications: Women who have been on hormone therapy or birth control pills for four or more years have a higher risk of breast cancer.
- Breast density: Breasts are considered “dense” when there is a high ratio of tissue to fat. Women with dense breasts are more likely to get breast cancer, although doctors aren’t sure why.
Signs and Symptoms
The first sign of breast cancer is usually a painless lump or thickening in the breast. However, when the tumor cannot be physically felt, symptoms usually appear in the later stages. Advanced symptoms include:
- A clear or tainted discharge from the nipple
- Retraction of the nipple
- Reddening of the skin over the breast
- A change in the breast’s contour or texture
Diagnosis and Staging
Many breast lumps can be detected with a self-examination called the palpation technique, which involves feeling for lumps in and around the breasts. A similar method is used in clinical exams for initial screening. When a lump is felt, the doctor uses X-ray mammography, CT and MRI scans, or other imaging techniques to get a better look at the mass.
When possible, invasive biopsies are avoided using a new method called ultrasound computed tomography. This system uses sound waves to create 3D images of the breast, showing a better picture of the tumor. If the results are unclear, however, a needle biopsy may still be performed to confirm the cancer.
After the diagnosis, the next step is determining the extent or stage of the cancer. The stages are as follows:
Stage 0: The cancer is still confined to the tissues or ducts, as is the case with DCIS
Stage I: The tumor is larger, but has not spread to the surrounding tissues and axillary (underarm) lymph nodes
Stage IIA: The tumor has grown to 2cm to 5cm, but has not affected any lymph nodes
Stage IIB: The tumor has spread to one to four lymph nodes, but is still within the 5cm limit
Stage IIIA: The tumor is greater than 5cm and has affected four or more lymph nodes
Stage IIIB: The cancer has affected four to 10 lymph nodes and has penetrated the skin or chest wall
Stage IIIC: More than 10 lymph nodes have been affected
Stage IV: The cancer has spread beyond the breast to distant organs, such as the lungs and liver
The prognosis depends on several factors, but the most important are the location, tumor size, and stage. Invasive ductal and lobular cancers usually have poor prognosis, because they grow faster and are more likely to spread. DCIS and medullary cancers have the highest survival rates.
Surgery is the treatment of choice for most types of breast cancer. New technologies have allowed surgical removal of the tumor while minimizing damage to the breast structure. Types of surgery include the following:
- Lumpectomy: only the lump and part of the surrounding normal tissue are removed. This is used for small early-stage tumors that have not spread.
- Partial mastectomy: the doctor removes the tumor, surrounding breast tissue, and some of the underlying chest muscles.
- Simple mastectomy: all of the breast tissue is removed, including the skin, fatty tissue, and milk ducts. This is used for invasive ductal and lobular cancers.
- Modified radical mastectomy: the entire breast is removed, along with some underarm lymph nodes. Unlike radical mastectomy, the chest muscles are left intact, making it possible to reconstruct the breast.
Most surgeries are followed by radiation therapy, a series of treatments involving high-energy X-rays. The rays kill remaining cancer cells and shrink the remaining tumor, if any. Chemotherapy is also used in late stage cancers, where the tumor has spread to distant organs.
Because the cancer first spreads to the axillary lymph nodes, most women also undergo a sentinel lymph node biopsy to check for metastasis after surgery. If cancer is detected in the lymph nodes, the doctor performs an axillary lymph node dissection (removal of the affected lymph nodes) to prevent further spread.
The best way to prevent breast cancer is regular mammography, especially for women over age 50. Most risk factors, such as drinking, smoking, and obesity, are easily avoided, so a lifestyle change can greatly lower one’s risk.
If a patient has one or more non-controllable factors (such as age and genetic predisposition), the doctor may suggest clinical procedures to lower the risk. The most common is “chemoprevention,” which involves a class of drugs known as selective estrogen receptor modulators (SERMs). These drugs control the body’s production of estrogen, which is believed to be a major factor in cancer development.