From the Guidelines
The most common type of breast cancer is invasive carcinoma of the breast, not otherwise specified (NOS), previously named ductal carcinoma, which accounts for approximately 70%–75% of all breast cancer diagnoses. This type of cancer is characterized by its origin in the milk ducts of the breast and its potential to invade surrounding breast tissue and spread to lymph nodes and other parts of the body 1. According to the World Health Organization (WHO) classification and the eighth edition of the American Joint Committee on Cancer (AJCC) tumour, node, metastasis (TNM) staging system, invasive carcinoma of the breast, NOS, is one of the two most frequent subtypes, with lobular carcinoma being the second most common, accounting for 12%–15% of all breast cancer diagnoses 1.
Key characteristics of invasive carcinoma of the breast, NOS, include its histological type, grade, and immunohistochemistry (IHC) evaluation of estrogen receptor (ER) status, progesterone receptor (PgR) status, and human epidermal growth factor receptor 2 (HER2) expression or gene amplification 1. The prognosis and treatment of this cancer type depend on these characteristics, as well as the presence or absence of ductal carcinoma in situ (DCIS) and the tumor's proliferation markers, such as the Ki67 labelling index 1.
Treatment options for invasive carcinoma of the breast, NOS, typically involve a combination of surgery, radiation therapy, chemotherapy, hormone therapy, and targeted therapy, depending on the specific characteristics of the tumor and the patient's overall health 1. Early detection through regular mammograms and breast self-exams is crucial for successful treatment, as the prognosis is generally better when the cancer is caught in earlier stages before it has spread beyond the breast.
From the Research
Types of Breast Cancer
- Invasive ductal carcinoma (IDC) is the most common type of breast cancer, primarily affecting women in the United States and across the world 2.
- IDC accounts for a significant proportion of breast cancer cases, with other types such as triple negative breast cancer (TNBC) being less common, accounting for 10-17% of all breast carcinomas 3.
Characteristics of Invasive Ductal Carcinoma
- IDC is characterized by its causes, including mutations on BRCA1 and BRCA2, different levels of expression of specific genes in signaling pathways, menopause status, alcohol consumption, aging, and hormone imbalances 2.
- Prompt IDC diagnosis and early intervention have been reported to demonstrate a greater probability of eradicating IDC and preventing further recurrence in the future 2.
Comparison with Other Types of Breast Cancer
- TNBC is only partially responsive to chemotherapy and suffers from a lack of clinically established targeted therapies, with a mean age of diagnosis of 49.6 years and a range of 27-82 years 3.
- Treatment with a combination of tamoxifen plus radiation has been shown to increase overall survival (OS) and reduce mortality rates in patients with TNBC and invasive ductal carcinoma 3.