Your gift is 100% tax deductible.
Invasive Breast Cancer: Invasive Ductal Carcinoma and Invasive Lobular Carcinoma
Breast cancers that have spread into surrounding breast tissue are known as invasive breast cancers. The two most common types are invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC).
Invasive ductal carcinoma (IDC)
Also known as infiltrating ductal carcinoma, IDC is the most common type of breast cancer. About 8 in 10 invasive breast cancers are IDC.
IDC starts in the cells that line the milk ducts in the breast. From there, the cancer breaks through the wall of the duct and invades (grows into) nearby breast tissues. At this point, it may be able to metastasize (spread) to other parts of the body through the lymph system and bloodstream.
Invasive lobular carcinoma (ILC)
About 1 in 10 invasive breast cancers are ILCs, also known as an infiltrating lobular carcinomas.
ILC starts in the lobules, the tiny breast glands that make milk. Like IDC, it can metastasize to other parts of the body, although it tends to take longer to do so.
Compared with other kinds of invasive carcinoma, ILC is more likely to affect both breasts. About 1 in 5 women with ILC have cancer in both breasts at the time they are diagnosed.
Less common types of invasive breast cancer
Other types of invasive breast cancer are much less common than IDC or ILC. These are often named after features of the cancer cells, like the way the cells are arranged.
Some tend to have a better prognosis (outlook) than the more common IDC:
- Adenoid cystic carcinoma (adenocystic carcinoma)
- Cribriform carcinoma
- Low-grade adenosquamous carcinoma (a type of metaplastic carcinoma)
- Medullary carcinoma
- Mucinous carcinoma (colloid carcinoma)
- Tubular carcinoma
Some types tend to have the same or possibly a worse outlook than IDC. These include:
- Metaplastic carcinoma (most types, including spindle cell and squamous, except for low-grade adenosquamous carcinoma)
- Micropapillary carcinoma
- Mixed carcinoma (cancers that have features of both IDC and ILC)
- Tubulolobular carcinoma
Treating invasive breast cancer
While there are some differences between the types of invasive breast cancer, they’re treated largely the same way. The type of 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.
- Written by
- 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: June 24, 2026
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
American Cancer Society Emails
Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.
