Understanding Your Diagnosis
Breast Cancer 101
Being diagnosed with breast cancer at a young age can stir up fear, grief, confusion, and every emotion in between. You may be trying to steady yourself and your loved ones while taking in unfamiliar terms, new appointments, and decisions you never expected to make.
This information is meant to help you untangle the overwhelming parts of your diagnosis and feel the strength, support, and compassion you deserve as you take the next steps.
Understanding the Basics
Breast cancer is the most common cancer in the U.S. excluding skin cancer. The breast is made up of:
- Lobules – glands that produce milk
- Ducts – tubes that carry milk to the nipple
- Connective tissue – fibrous and fatty tissue that supports the breast
Breast cancer occurs when breast cells grow abnormally and form tumors. The type of breast cancer depends on which cells become cancerous, with most starting in the ducts or lobules.
Understanding breast cancer subtypes has allowed physicians to personalize treatment based on tumor type, stage of disease, and overall health and preferences. This helps them tailor systemic therapy, radiation therapy, and surgery more precisely.
A tumor’s stage, grade, and receptor status are important in determining an effective treatment plan. More detail on these terms appears below.
Stage
Breast cancer stage describes where the tumor is located and how much cancer is present. Early breast cancer ranges from stage 0 to stage III, and in general, the higher the stage, the higher the risk of recurrence (when cancer returns in the breast or elsewhere in the body). Stage IV is the most advanced stage of breast cancer.
Stage 0: Ductal Carcinoma in Situ (DCIS)
Also called pre-invasive breast cancer, DCIS is highly treatable and very curable
Stages 1–3: Early Invasive Breast Cancer
Invasive breast cancer means the tumor has spread from the milk duct or lobule into surrounding breast tissue.
Stage 4: Metastatic Breast Cancer (MBC)
Metastatic breast cancer occurs when cancer spreads to other parts of the body, such as the bones, brain, liver, or lungs.
Tumor Grade: How it Helps Guide Care
Tumor grade describes how cancer cells look under a microscope compared to normal breast cells. This helps predict your prognosis and guides which treatments may work best.
Grade 1 (low grade)
Cancer grows more slowly and is less likely to spread or return after treatment.
Grade 2 (intermediate grade)
Growth rate is between grade 1 and grade 3.
Grade 3 (high grade)
Cancer grows more quickly and is more likely to spread or return.
Receptor Status: What It Tells You
Receptor status describes whether breast cancer cells carry certain proteins that influence how the cancer grows and which treatments may work.
