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Formerly known as California Oncology of the Central Valley Request an Appointment
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Formerly known as California Oncology of the Central Valley Request an Appointment

Breast Cancer

What Is Breast Cancer?

Breast cancer occurs when cells in the breast grow out of control. Benign breast tumors do not have the ability to spread, but malignant tumors can grow into other tissues and spread to other organs throughout the body.

Diagram of the makeup of the breasts

The breasts are collections of lymph vessels, blood vessels, glands, and fatty tissue that cover the chest muscles. The glands within the breast, also called lobes, are made up of lobules that produce milk after a woman gives birth. Milk travels from the glands to the nipple through small tubes called ducts. The breasts enlarge when glands and ducts are full of milk, but the fatty tissue in the breast makes up most of its size and shape. Lymph fluid is drained from the breast into lymph nodes in the armpit, which filter the lymph fluid.

Difference between a normal and cancerous breast cancer cell

Types of Breast Cancer

This is the second most common cancer for women in the United States. The cancer can form in any breast tissue, but it is most commonly found in the ducts and the glands. These are some of the more common types.

Ductal Carcinoma

The most common type of breast cancer, ductal carcinoma, originates in the lining of the ducts. Ductal carcinoma in situ (DCIS) refers to precancerous cells that have not yet spread outside of the ducts but have the ability to spread if left untreated. Invasive ductal carcinoma has spread from the ducts to nearby breast tissue.

Lobular Carcinoma

Lobular carcinoma begins in the lobes of the breast. Similar to DCIS, lobular carcinoma in situ (LCIS) indicates precancerous cells in the lobes and increased risk for cancer, but treatment may not be necessary unless a true cancer is also present. Invasive lobular carcinoma has spread from the lobes to other breast tissue.

Triple Negative Breast Cancer

Accounting for 10-15% of all breast cancers, this type of cancer tests negative for estrogen receptors, progesterone receptors, and HER2 protein. These are the three most common fuels for this cancer’s growth, which means it is more difficult to target the cancer—hormone therapies and treatments targeting estrogen, progesterone, and HER2 are not effective. This type is also referred to as ER/PR negative and HER2 negative.

Inflammatory Breast Cancer

There is no lump or tumor with this inflammatory cancer, which makes up less than 5% of breast cancer diagnoses but is one of the more aggressive types. Specific symptoms include swelling, redness, tenderness, warmth, itchiness, and enlargement. The skin may become dimpled or thickened, like a citrus peel.


Women are more at risk for breast cancer because the female body naturally produces more estrogen and progesterone, which can promote cancer growth. Men can develop breast cancer too, but they only make up about 1% of cases. As a woman ages, her risk for this type of cancer also increases. Other risk factors include starting menstruation at a young age, older age for a first pregnancy, being overweight, drinking more than five alcoholic beverages per week, history of radiation to the chest, history of breast cancer, dense breast tissue, and taking estrogen. Family history can be an indication of risk as well, but every situation is unique, so discussing family history is essential. These cancer risk factors necessitate more frequent tests and screenings.

Genetic Mutations

Some genetic mutations are specifically known to increase the risk of breast cancer, including mutations in the genes BRCA1 and BRCA2, which are known as breast and ovarian cancer syndrome. These genes can be inherited from parent or arise for the first time. If tests confirm the presence of a mutation, some choose to undergo more intense screenings or take preventive measures, like surgery, to decrease the chances of developing cancer later on.

Cell Receptor Status

Breast cancer cells can have hormone receptors. When the female hormones estrogen and progesterone attach to the cancer cell receptors, they feed the cells and help them grow more quickly. Tests can determine whether there are hormone receptors on the cancer cells, and results are either estrogen (ER) positive or negative or progesterone (PR) positive or negative. Medication known as hormone blockers can be given to block the positive hormone receptors, which slows or stops the cancer growth.

HER2 stands for hormone epidermal growth factor receptor-2. When there is an excess amount of this protein, the cancer cells are recognized as HER2 positive. Medications can target and block HER2 to slow or stop the growth of the cancer cells.


  • Lump or thickening in the breast or armpit
  • Change in size or shape of the breast
  • Change in skin texture of breast; scaling, ridges, or pitting
  • Nipple discharge
  • Nipple turning inward
  • Redness or swelling on the breast

Tests & Exams

Some tests are performed by primary care providers or OB/GYNs as part of routine screenings, while others are done after receiving abnormal results to learn more. Detecting breast cancer early increases the chance that it is treatable.

  • Screening mammograms
  • 3D mammograms
  • BRCA test
  • CT scan
  • MRI
  • Ultrasound
  • Biopsy
  • PET Scan


Staging is a measurement system based on the size of the tumor and how far it has spread in the body. Using the TNM system, all of the information from tests and examinations is then combined and assessed to determine the stage, from I (one) to IV (four). Generally, the higher the stage, the more serious the cancer.

TNM System

(Tumor – node – metastasis system)

  • T: shows how far the main tumor has spread into nearby tissue
  • N: shows whether or not the nearby lymph nodes have cancer in them
  • M: shows if the cancer has spread (or metastasized) to distant organs in the body
Stage 0
Stage I
Stage II
Stage III
Stage IV

Stage 0

If left untreated, these cells will likely become invasive ductal or lobular carcinoma. This stage is also called carcinoma in situ.

Stage 0 Breast Cancer

Stage I

Cancer cells have formed but the tumor is less than 2 cm and has not spread beyond the breast. This is considered “early-stage breast cancer.”

Stage I Breast Cancer

Stage II

The tumor is either less than 2 cm and has spread to the lymph nodes, the tumor is 2-5 cm, or the tumor is larger than 5 cm and has not spread. This is considered “early-stage breast cancer.”

Stage III

The tumor is larger than 5 cm and has spread to the lymph nodes, the cancer is extensive in the lymph nodes, or the cancer has spread to other breast tissues. This is considered “advanced breast cancer.”

Stage III Breast Cancer

Stage IV

Cancer has spread beyond the breast and surrounding tissue to other organs in the body. This is considered “advanced breast cancer.”

Stage IV Breast Cancer


The grade of an illness refers to how the cancer cells look when compared to normal cells. The lower the number, the more cancer cells look like the normal cells. This means the cancer is less likely to spread and may be easier to treat. Grade 3  looks very different from normal cells and is likely to grow and spread faster.

Different grades of breast cancer cells

Breast Cancer Treatment

There are numerous treatment options that vary based on the extent of the disease. Some treatments are completed in our office, while others would be coordinated and performed by partner members of the patient care team outside of our office.

In-Office Therapies

Other Courses of Treatment

Radiation Therapy

This type of treatment uses radiation to kill breast cancer cells or stop them from growing. The method and dosage of radiation therapy are dependent on the extent of the cancer.


Most women diagnosed with breast cancer will undergo surgery during the course of their treatment to remove as much of the cancer as possible. A mastectomy is a surgery that removes the entire breast. Breast conserving surgeries (BCS) are effective for some people, where only a portion of breast tissue is removed in a lumpectomy or partial mastectomy. The lymph nodes in the armpit may also need to be biopsied or removed. Breast reconstruction surgery is also an option for many women following the completion of treatment.