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Invasive Ductal Carcinoma
Breast cancers that have spread into surrounding breast tissue are known as invasive breast cancers. The most common type is invasive ductal carcinoma.
What is invasive ductal carcinoma (IDC)?
IDC is the most common type of breast cancer. About 3 out of 4 invasive breast cancers are IDC.
It is also known as:
- Infiltrating ductal carcinoma
- Invasive breast carcinoma of no special type (IBC-NST)
When IDC is looked at under a microscope, the cancer cells form solid clusters or tubes, similar to the shape of a breast duct. Ducts are the small tubes that carry breast milk from the lobules, which make the breast milk, to the nipples.
IDC is called an invasive cancer because the cells have broken through the wall where they started and invaded (grown into) nearby breast tissues. At this point, the cancer might be able to metastasize (spread) to other parts of the body through the lymph system and bloodstream.
Treating IDC and other invasive breast cancers
Although there are some differences between IDC and other types of invasive breast cancer, such as invasive lobular carcinoma (ILC), they’re treated largely the same way. The type of breast cancer can sometimes play a role when deciding on certain treatments, but in general, other factors are more important, including:
- How advanced the cancer is (the stage of the cancer)
- Whether the cancer cells have hormone receptors, too much of the HER2 protein, or certain other gene or protein changes
Most people will have some type of surgery to remove the tumor in the breast. Depending on how advanced the cancer is and other factors, other types of treatment might be needed as well, either before or after surgery, or sometimes both.
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Bleiweiss IJ. Pathology of breast cancer. UpToDate. 2026. Accessed at https://www.uptodate.com/contents/pathology-of-breast-cancer on April 3, 2026.
Henry NL, Shah PD, Haider I, Freer PE, Jagsi R, Sabel MS. Chapter 88: Cancer of the Breast. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa: Elsevier; 2020.
Jagsi R, King TA, Lehman C, Morrow M, Harris JR, Burstein HJ. Chapter 79: Malignant Tumors of the Breast. In: DeVita VT, Lawrence TS, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 11th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2019.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Breast Cancer. Version 2.2026. Accessed at https://www.nccn.org on April 3, 2026.
Last Revised: August 26, 2026
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
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