A breast cancer diagnosis is unique to each person. While there are general categories, it’s important to speak with your health care team to understand your specific diagnosis, staging, and treatment options.
Ductal Carcinoma in Situ (DCIS) Ductal carcinoma in situ is the earliest form of breast cancer, sometimes called Stage 0. The abnormal cells are confined to the milk ducts and have not spread into surrounding breast tissue. DCIS is most commonly detected through screening mammography, often appearing as tiny calcium deposits. It is highly treatable, with a nearly 100% survival rate when caught early. Treatment typically involves surgery (lumpectomy or mastectomy), often followed by radiation therapy and sometimes hormone therapy.
Infiltrating Ductal Carcinoma (IDC) Also called invasive ductal carcinoma, IDC is the most common type of breast cancer, accounting for approximately 70–80% of all diagnoses. Cancer cells originate in the milk ducts and break through the duct wall into surrounding breast tissue, with potential to spread to lymph nodes and other parts of the body. Treatment depends on stage, grade, and receptor status (ER, PR, HER2), and may include surgery, chemotherapy, radiation, hormone therapy, or targeted therapy.
Infiltrating Lobular Carcinoma (ILC) Also called invasive lobular carcinoma, ILC begins in the milk-producing lobules and accounts for about 10–15% of invasive breast cancers — a figure updated upward from older estimates. It is most common in women aged 45–56. ILC can be harder to detect on mammograms because it tends to grow in a single-file pattern rather than forming a distinct lump. MRI may be recommended for more accurate staging. Treatment options are similar to IDC. Read more.
Lobular Carcinoma in Situ (LCIS) LCIS is not technically a cancer but rather a marker of increased risk. Abnormal cells grow inside the lobules without invading surrounding tissue. Current guidelines (NCCN 2024) classify LCIS as a risk factor — women with LCIS have a 7–12 times greater lifetime risk of developing invasive breast cancer in either breast. Management options include active surveillance with regular mammograms and MRIs, risk-reduction medications (such as tamoxifen or raloxifene), or preventive surgery in high-risk cases.
Triple-Negative Breast Cancer (TNBC) TNBC tests negative for estrogen receptors, progesterone receptors, and HER2 protein, meaning it does not respond to hormone therapy or HER2-targeted drugs. It accounts for about 10–15% of all breast cancers and tends to be more aggressive. TNBC is more common in younger women and those with BRCA1 mutations. Treatment relies on chemotherapy, and newer options include immunotherapy (pembrolizumab) and PARP inhibitors for BRCA-related cases.
HER2-Positive Breast Cancer HER2-positive breast cancer overexpresses the HER2 protein, driving faster cell growth. It accounts for about 15–20% of cases. While historically more aggressive, outcomes have dramatically improved with targeted therapies such as trastuzumab (Herceptin), pertuzumab, and the newer antibody-drug conjugate trastuzumab deruxtecan (T-DXd). HER2 status is now routinely tested at diagnosis.
Inflammatory Breast Cancer (IBC) IBC is a rare but aggressive form, accounting for 1–5% of breast cancer cases. It typically does not present as a lump. Instead, the breast may appear red, swollen, warm, and have a texture resembling an orange peel (peau d’orange) due to cancer cells blocking lymph vessels. IBC is often diagnosed at Stage III or IV and requires prompt treatment, usually beginning with chemotherapy before surgery. Read more
Rare Types A small percentage of breast cancer diagnoses involve rare subtypes, including Paget’s disease of the nipple, phyllodes tumors, angiosarcoma, adenoid cystic carcinoma, and metaplastic breast cancer. A rare diagnosis does not automatically mean a worse outcome — treatment and prognosis vary by subtype and should be discussed with a specialist, ideally at a comprehensive cancer center.
Male Breast Cancer Men have breast tissue and can develop breast cancer, though it accounts for less than 1% of all breast cancer cases. IDC is the most common type in men. Risk factors include elevated estrogen levels, BRCA2 gene mutations, Klinefelter syndrome, and family history. Because awareness is lower, male breast cancer is often diagnosed at a later stage. Treatment follows similar principles to female breast cancer, though clinical trial access and support resources have historically been more limited for men. Read more
