Invasive carcinoma of no special type (NST) is the most common form of invasive breast cancer, accounting for up to 80% of cases. The name “no special type” indicates that when viewed under a microscope, the cancer cells do not have the distinguishing characteristics that would classify them as a rarer, “special” type of breast cancer.
This condition was previously known as invasive ductal carcinoma (IDC), and this term is still sometimes used. The “invasive” part of the name means cancer cells that originated inside the milk ducts have broken through the duct walls and grown into the surrounding breast tissue. It is the most common type of breast cancer found in both women and men.
The Diagnostic Process
The diagnostic process often begins with the detection of an abnormality, such as a lump found during an exam or an unusual area on a screening mammogram or ultrasound. Symptoms can include a change in breast size or shape, skin dimpling, nipple retraction or discharge, or redness of the skin. These signs prompt further investigation.
To confirm the presence of cancer and determine its type, a biopsy is performed. This procedure involves removing a small sample of the suspicious tissue, which is sent to a pathologist for analysis. The pathologist examines the cells under a microscope to identify if cancer is present and to note its characteristics.
An NST diagnosis is confirmed based on the microscopic appearance of the cells. Following this identification, the biopsy sample undergoes further testing for biomarkers. These tests determine the presence of receptors for estrogen (ER) and progesterone (PR), and the level of a protein called HER2. The results of these receptor tests guide treatment decisions.
Understanding Grade and Stage
After a diagnosis is confirmed, pathologists and oncologists determine the cancer’s grade and stage. These two measures provide different but important information. Grade describes the appearance of the cancer cells, while stage describes the cancer’s size and spread, which helps in planning the most effective treatment.
The tumor’s grade describes how abnormal the cancer cells look compared to healthy breast tissue. Pathologists use a system like the Nottingham Grading System, scoring the tumor from 1 to 3. A Grade 1 tumor means the cells appear more like normal cells and are slower-growing, while Grade 3 tumors are poorly differentiated and tend to grow more quickly. Grade 2 falls in between these descriptions.
The cancer’s stage indicates the tumor’s size and how far it has spread from the breast. The TNM staging system is used, where “T” is tumor size, “N” is spread to nearby lymph nodes, and “M” is metastasis to distant parts of the body. This information is combined to assign an overall stage from 0 to IV, providing a standard description of the cancer’s extent.
Treatment Approaches
The treatment plan for NST is personalized based on the tumor’s grade, stage, and biomarker status (ER, PR, and HER2), as well as the patient’s health. Treatments are categorized into local therapies, which target the cancer in the breast area, and systemic therapies, which work throughout the body.
Local treatments focus on removing or destroying the tumor at its source. Surgery is often the first step, with options including a lumpectomy (removing the tumor and a margin of tissue) or a mastectomy (removing the entire breast). Radiation therapy may follow a lumpectomy to eliminate any remaining cancer cells and reduce the risk of recurrence.
Systemic treatments are designed to reach cancer cells throughout the body, with the specific therapy linked to the cancer’s biomarker status. These treatments can be used alone or in combination.
- Hormone therapy is used for ER-positive or PR-positive tumors to block hormones from fueling cancer growth.
- Chemotherapy may be recommended for higher-grade or larger tumors to kill fast-growing cells.
- Targeted therapy drugs are used for HER2-positive cancers to attack the HER2 protein.
- Immunotherapy may be an option for triple-negative cancers to help the body’s immune system fight the cancer.
Prognosis and Follow-Up Care
The prognosis for NST is influenced by the cancer’s grade, stage, biomarker status, and treatment effectiveness. While survival rates are statistics and cannot predict an individual outcome, the outlook for this cancer is favorable when detected early.
Consistent follow-up care is a part of long-term health and recovery. This includes regular check-ups with the oncology team, involving physical exams, blood tests, and imaging scans like mammograms. This surveillance helps monitor for any signs of recurrence so that new developments can be addressed promptly.
Managing long-term treatment side effects is also a focus of follow-up care. Patients work with their healthcare providers to address issues like lymphedema, fatigue, or the effects of hormone therapy. Regular communication with the medical team and adhering to the follow-up schedule are components of life after a breast cancer diagnosis.