Decoding Your Diagnosis - Breast Cancer Types

Toyree Davis, MSN, NP: Toyree Davis is a board-certified Nurse Practitioner with 12 years experience in medical oncology. She is chemotherapy and biotherapy certified. Toyree’s early career focused on all cancer populations and in recent years has focused exclusively on breast cancer, head & neck, and lung cancer populations. She achieved her Master of Science in Nursing as a Family Nurse Practitioner at the University of Memphis. She is passionate about early detection and helping the community to become more informed about preventative cancer screenings and awareness.

Holly is a writer, performer, and health advocate, sharing her personal experience as a breast cancer survivor and carrier of the BRCA1 gene mutation to raise awareness, and support women as they navigate their own cancer journey - practically, spiritually, and emotionally. With training and background in Reiki, spirituality, and holistic health/wellness, her writing runs the gamut from being a regular contributor at The Huffington Post, to produced playwright, to Senior Writer for a global non-profit.

It’s not enough that it feels like the rug was pulled out from under you with the news you have breast cancer. Now, all sorts of terminology describing the specifics of said breast cancer are being thrown at you.

In this series of “Decoding Your Diagnosis” articles, we’re giving you a cliff’s notes version of that terminology, because we believe that understanding the type, grade, stage, and characteristics of your tumor can give you a better understanding of why your doctor is suggesting certain treatment options. 

However, in this series, we are not delving into those suggested treatment options for each; that is something for you to discuss with your doctor–we’re just setting the “stage” (wink face). 

One of the first things that get diagnosed is the type of breast cancer you have, which generally falls under two categories: In-situ and Invasive, sometimes called infiltrating. Here’s the low-down. 

In Situ

The earliest stages of breast cancer are considered “in situ,” meaning “in the original place.” 

There are two types:

  1. Ductal Carcinoma In Situ (DCIS)- DCIS, also known as intraductal carcinoma or stage 0,  is the earliest stage of breast cancer, in which abnormal  cells have been found in the lining of the milk duct, but have not spread to surrounding breast tissue. It is, therefore, non-invasive or pre-invasive.  
  2. Lobular Carcinoma In Situ (LCIS)- LCIS, also known as lobular neoplasia, is a rare condition in which abnormal cells develop in the lobules (milk glands). LCIS is not actually considered a cancer, nor does it usually become an invasive cancer; it does, however, increase the risk of either breast developing cancer in the future.


There are three types of invasive, or infiltrating, breast cancers, in which the cancer cells have grown and broken out of their original location in the breast to surrounding breast tissue; therefore, they have the potential to spread through the blood and lymph systems to other parts of the body.

Invasive ductal carcinoma (IDC) 

IDC is the most common type of breast cancer, representing 70- 80% of all diagnoses… and not to leave out the menfolk, it is also the type of breast cancer that most commonly affects them. 

Beginning in the milk duct, IDC has grown to invade the surrounding breast tissue. 

There are subtypes within the IDC category that further describe the appearance and aggressiveness/behavior which can guide treatment decisions including Tubular Carcinoma, Medullary Carcinoma, Mucinous Carcinoma, Papillary Carcinoma, and Cribriform Carcinoma. 

Invasive Lobular Carcinoma (ILC)

ILC makes up 10-15% of breast cancer diagnoses and is similar to IDC except that the invading cells began in the lobules.

Mammograms are less likely to detect invasive lobular breast cancer than the other types, so if you have breast cancer in your family, or are concerned, it is best to get an MRI. 

There are subtypes of ILC, but they describe the pattern or appearance and do not typically have an effect on aggressiveness or grade.

Inflammatory breast cancer (IBC) 

IBC is an uncommon (1-5%) but a fast-growing type of invasive cancer, in which the cancer cells block the breast’s lymph vessels in the skin, causing symptoms of inflammation.  Since IBC has infiltrated the skin, it is classified as Stage 3.

Heads up that IBC has a style all its own, and doesn’t look like a typical breast cancer; therefore, it might not show up on a mammogram because it doesn’t always cause a lump.

Rare Types of Breast Cancer

There are two other rare types of breast cancer you might hear about. 

  1. Paget’s disease of the nipple in which cancer cells collect in or around the nipple.
  2. Phyllodes tumors account for less than 1% (“phyllodes," comes from Greek, meaning  "leaflike,” because the tumor cells grow in a leaflike pattern) account for less than 1% of all breast tumors. While most phyllodes tumors are benign; however, some are malignant and some are borderline (in between noncancerous and cancerous)

As with everything in life, things can get more complicated than these primary breast cancer types, including molecular subtypes based on the gene cancer expresses, some cancers affecting other cells in the breast, or some having special features that can affect treatment.

If you ever have any questions about your diagnosis, we encourage you to ask your care team, because here at Stage we believe knowledge is empowering.

It’s not enough that it feels like the rug was pulled out from under you with the news you have breast cancer. Now, all sorts of terminology describing specifics of said breast cancer is being thrown at you. Here’s a cliff’s notes version of that terminology to help set the stage (see what we did there?) for your treatment and journey.

- Holly Sidell

Leave a comment

Please note, comments must be approved before they are published

Explore Articles