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Invasive Ductal Carcinoma: What To Know About the Most Common Type of Breast Cancer 

By BCRF | February 15, 2024

Learn about invasive ductal carcinoma and how BCRF investigators are driving advances in prevention, treatment, and more

Invasive ductal carcinoma, also called infiltrating ductal carcinoma (IDC) and invasive ductal breast cancer, is the most common type of breast cancer followed by invasive lobular carcinoma (ILC). Incidence rates of invasive ductal carcinoma have increased over the past 20 years. In 2023, an estimated 297,790 new cases of invasive breast cancer will be diagnosed in the U.S.

Though breast cancer is much more common in females than in males, about 98 percent of male breast cancers are invasive ductal carcinoma. Because it is the most common type of breast cancer in both females and males, research is heavily focused preventing and treating primary invasive ductal carcinoma as well as on preventing and treating its metastasis to distant sites in the body.

What is invasive ductal carcinoma?

Invasive breast cancers, which represent 83 percent of breast cancers, are abnormal cells that have broken through the walls of their original sites and invaded surrounding breast tissue. Approximately 75 percent of invasive breast cancers are invasive ductal carcinoma, which originates in the cells lining the milk ducts of the breast. A less common type of invasive breast cancer, invasive lobular carcinoma, begins in the milk-producing lobular glands of the breast and makes up about 10 percent of invasive breast cancers. There is also inflammatory breast cancer, which comprises about 0.3 percent of invasive breast cancers. While rare, inflammatory breast cancer is aggressive and spreads to the skin of the breast, causing redness and inflammation.

In contrast, non-invasive breast cancers stay in the area of the breast where they first form. The most common non-invasive breast cancer, ductal carcinoma in situ (DCIS), is contained in the milk ducts and has not infiltrated other tissue. Similarly, lobular carcinoma in situ (LCIS) is contained within the lobules.

Breast cancer is further sub-categorized into subtypes by molecular features that influence how they present clinically, how they respond to therapies, and prognosis. The molecular characteristics of invasive ductal carcinoma listed below from NCI’s SEER research data provide options for hormone and targeted therapies to reduce the risk of recurrence:

  • 69 percent of invasive breast cancer, most of which is invasive ductal carcinoma, is driven by hormones, or hormone (estrogen/progesterone) receptor (HR)–positive.
  • 4 percent of invasive breast cancer is HER2-positive and HR-negative, meaning that the cancer cells make a higher-than-normal amount of the HER2 protein, which drives tumor growth.
  • 10 percent of invasive breast cancer is both HER2-positive and HR-positive and are driven by both hormones and HER2.
  • 10 percent of invasive breast cancer is triple-negative breast cancer (TNBC), which has neither HR nor HER2.
  • 7 percent of invasive breast cancer is of an unknown molecular subtype.

What causes invasive ductal carcinoma?

The causes of invasive ductal carcinoma are not fully understood, but certain risk factors have been identified. These include:

  • Smoking
  • Alcohol use
  • Being overweight
  • Prior radiation to the chest
  • Early start of menstrual periods
  • Late menopause
  • Never being pregnant
  • Having children later in life

Invasive ductal carcinoma has been linked to hereditary factors in five to 10 percent of cases. Mutations in BRCA1, BRCA2, and other genes such as PALB2, CHEK2, and ATM increase one’s risk of developing breast cancer and can be passed on in families by both women and men.

What are invasive ductal carcinoma symptoms?

Breast cancer is the uncontrolled growth and division of cells in breast tissue, which typically causes the formation of a lump in the breast over time. The most common invasive ductal carcinoma symptoms are a new painless lump in the breast, either too small to feel or large enough to be felt, or suspicious calcifications detected via mammography that require further testing. Other possible invasive ductal carcinoma symptoms include:

  • Swelling of the breast
  • Breast pain (mastalgia)
  • Nipple pain
  • Dimpling
  • Skin irritation
  • Redness or scaliness
  • A lump near the armpit
  • Inverted nipple
  • Thickening of the breast skin or nipple
  • Discharge from the nipple that isn’t breast milk

How is invasive ductal carcinoma diagnosed? 

Invasive ductal carcinoma can be detected by screening mammography before there are any noticeable signs or symptoms, underscoring the importance of routine screening and early detection. Mammography and ultrasound are the standard tools used for breast imaging and can reveal small masses, calcifications, and other abnormalities that are indicative of breast cancer. In some cases, MRI may be recommended, which can detect small lesions. This tool is useful in examining patients with a high risk of breast cancer, such as those with mutations in breast cancer susceptibility genes including BRCA, PALB2, CHEK2, and ATM.

Possible breast cancer identified via imaging is then biopsied and the sample tissue is carefully examined under a microscope. A biopsy can rule out or confirm the presence of breast cancer. If breast cancer is identified, it is then graded and staged to characterize it and describe how far the breast cancer has spread.

Invasive ductal carcinoma treatment

Invasive ductal carcinoma is treated in several ways depending on the size of the tumor, its stage and molecular subtype, and how far the cancer has spread. Patients treated for invasive ductal carcinoma often receive some combination of the following treatment options:

  • Surgery, such as lumpectomy or mastectomy, may be used to remove the tumor in early-stage invasive ductal carcinoma cases or the entire breast in late-stage invasive ductal carcinoma cases.
  • Radiation therapy is often used after lumpectomy to ensure that any residual cancer cells are destroyed and to prevent breast cancer recurrence.
  • Systemic therapies may be used to treat invasive ductal carcinoma and vary based on the tumor characteristics. Systemic therapies for invasive ductal carcinoma include chemotherapy, hormone therapy, and targeted therapy, which specifically targets a driver of tumor growth.

When discovered and treated early, the 5-year invasive ductal carcinoma survival rate is nearly 100 percent. If the cancer has spread to nearby tissue or metastasized to other areas of the body, the 5-year survival rate drops. New treatments are continually being developed and tested in clinical trials, and the prognosis for advanced invasive ductal carcinoma continues to improve.

Invasive ductal carcinoma research

Breast cancer is the most commonly diagnosed cancer in women worldwide, with over 1.84 million new cases of invasive ductal carcinoma diagnosed in 2022. Because the majority of breast cancer is invasive ductal carcinoma, breast cancer research largely focuses on this type of breast cancer and on the challenges survivors face.

Understanding the facets of invasive ductal carcinoma—from its fundamental biology to how it can be effectively treated at every stage—is critical to improving outcomes. BCRF investigators are researching every aspect of the disease and have been deeply involved in every major advance in breast cancer prevention, diagnosis, treatment, and survivorship over the last 30 years.

BCRF continues to be at the forefront of invasive ductal carcinoma research and supports work in every area, including:

  • Discovery of breast cancer stem cells, understanding how breast cancer originates in the body, and how breast cancer stem cells can be targeted to prevent breast cancer progression and metastasis
  • Gaining a deeper understanding of the role of genetics in breast cancer risk, identifying populations who are at greater risk, and discovering novel inherited causes
  • Developing precision therapies based on an individual’s tumor biology to personalize treatment
  • Better predicting how a tumor will respond to treatment and the risk of recurrence
  • Optimizing treatment for low-risk breast cancer to avoid unnecessary side effects and improve quality of life
  • Leveraging the immune system to better fight breast cancer and identifying how immune cells interact with cancer cells to block or promote tumor growth
  • Preventing breast cancer through the development of vaccines
  • Improving disparities in breast cancer outcomes by analyzing and combating contributing factors in affected populations
  • Conducting studies to improve quality of life during and after treatment, including reducing cancer-associated stress, fatigue and treatment side effects, and improving fertility preservation
  • Understanding how lifestyle, or modifiable risk factors, are linked to breast cancer risk and survival

BCRF is committed to supporting exceptional, collaborative research to break new ground and ultimately save lives.

Selected References:

Breast Cancer Treatment. (2019). National Cancer Institute;

Cleveland Clinic. (2021, November 29). Invasive (Infiltrating) Ductal Carcinoma: Grades, Treatments & Prognosis. Cleveland Clinic.

Invasive Breast Cancer (IDC/ILC). (n.d.).

Cancer Stat Facts: Female Breast Cancer Subtypes (n.d.). SEER.

Wright, P. (2023). Invasive Ductal Carcinoma (IDC).