Types of Tumors

Although breast cancer is often referred to as one disease, there are many different types of breast cancer.

While all breast cancers start in the breast, they differ in other ways. They can be non-invasive or invasive. Tumor cells can vary in location (milk ducts or lobules) and how they look under a microscope. These differences often affect prognosis.

Tumor characteristics, such as hormone receptor status and HER2 status, also affect prognosis.

Learn more about factors that affect prognosis.

Non-invasive and invasive breast cancers

A pathologist looks at the tissue removed during a biopsy under a microscope to check whether a tumor is non-invasive (ductal carcinoma in situ) or invasive breast cancer.

Ductal carcinoma in situ (DCIS)

Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer. In situ means “in place.” With DCIS, the abnormal cells are contained in the milk ducts of the breast and have not spread to nearby breast tissue.

Although DCIS is non-invasive, without treatment, the abnormal cells could progress to invasive breast cancer over time. You may also hear the terms “pre-invasive” or “pre-cancerous” to describe DCIS.

With treatment, prognosis (chance of survival) for DCIS is usually excellent.

Learn about breast anatomy.

Invasive breast cancer

Invasive breast cancer has spread from the original site (either the milk ducts or the lobules) into the nearby breast tissue, and possibly to the lymph nodes and other parts of the body.

For this reason, invasive breast cancers have a poorer prognosis than DCIS.

Learn about breast anatomy.

Types of invasive breast cancer

Figure 4.6 lists types of invasive breast cancer.

Invasive ductal carcinoma is the most common type of breast cancer (70-80 percent of all breast cancers) [17-18]. It may also be called infiltrating ductal carcinoma, invasive carcinoma of no special type or invasive carcinoma not otherwise specified.

Invasive lobular carcinoma is the next most common type (about 5-10 percent of breast cancers) [18-19].

Figure 4.6: Prevalence and Tumor Characteristics of Different Types of Invasive Breast Cancer
Type of invasive breast cancer	Proportion of all invasive breast cancers	Tumor characteristics	Prognosis
Invasive ductal carcinoma (IDC)	70-80%	Hard tumor texture Tumor is irregular, star-shaped Cell features vary DCIS often present	Prognosis varies with stage and grade of tumor
Invasive lobular carcinoma (ILC)	5-10%	Normal, slightly firm or hard tumor texture Cells most often appear in single file order Tumors are most often ER-positive and HER2-negative	Prognosis varies with stage and grade of tumor For any given stage or grade, prognosis is similar to that of IDC Pattern of metastases may be slightly different from IDC (for example, ILC may metastasize to the gastrointestinal tract or the ovaries)
Tubular carcinoma	1-2%	Tumors are most often small Often no palpable tumor Cells form tube-like structures Tumors are almost always ER-positive and HER2-negative	Prognosis is usually better than for IDC Rare for cancer to spread to lymph nodes or other parts of the body
Mucinous (colloid) carcinoma	2%	Soft tumor Often no palpable tumor Cells are surrounded by excess mucous (mucin) Tumors are most often ER-positive and HER2-negative	More common among older women Tends to have a good prognosis Less common for cancer to spread to lymph nodes
Carcinomas with medullary features	1%	Soft tumor Cells have a sheet-like appearance Tumors tend to be triple negative (ER-negative, PR-negative and HER2-negative)	More common among younger women and women with a BRCA1 inherited gene mutation
Invasive papillary carcinoma	1%	Soft tumor Cells appear as fingerlike branches	More common in women after menopause Tends to have a good prognosis
* Percentage is higher in cancers found through mammography screening. ER-positive = estrogen receptor-positive ER-negative = estrogen receptor-negative PR-negative = progesterone receptor-negative HER2-negative = HER2 receptor-negative
Adapted from select sources [17-19].

Special invasive breast cancers and carcinoma in situ

 

Susan G. Komen® Support Resources

If you or a loved one needs more information about breast health or breast cancer, contact the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636) or helpline@komen.org. All calls are answered by a trained specialist or oncology social worker, Monday through Friday from 9:00 a.m. to 10:00 p.m. ET. Se habla español. Komen Patient Navigators can help guide you through the health care system as you go through a breast cancer diagnosis. They can help to remove barriers to high-quality breast care. For example, they can help you with insurance, local resources, communication with health care providers and more. Call the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636) or email helpline@komen.org to learn more about our Patient Navigator program, including eligibility. Komen Facebook groups provide a place where those with a connection to breast cancer can share their experiences and build strong relationships with each other. Visit Facebook and search for “Komen Breast Cancer group” or “Komen Metastatic Breast Cancer group” to request to join one of our closed groups. Our fact sheets, booklets and other education materials offer additional information.

Other types of cancer that occur in the breast

Most cancers that occur in the breast are breast cancers (breast carcinomas).

In rare cases:

• Other types of cancer, such as lymphomas (cancer of the lymph system) and sarcomas (cancer of the soft tissues), can occur in the breast.
• Cancers from other sites can metastasize (spread) to the breast and mimic breast cancers.

Some of these cancers are not carcinomas. Others are carcinomas, but they don’t start in the breast. So, they are treated differently and have different risk factors than breast cancer.

For more information on other cancers that can occur in the breast, such as lymphomas, sarcomas and malignant phyllodes tumors, visit the National Cancer Institute’s website.