As the biology of breast cancer becomes better understood, treatments are being increasingly tailored to the individual person and tumour factors. Understanding the histopathology and stage of breast cancer is important for determining treatment options, and supporting the person diagnosed to understand their likely care pathway and prognosis.
The majority of invasive breast cancer starts in the ducts or lobules of the breast. Other less common types of breast cancer include inflammatory breast cancer, medullary carcinoma and Paget disease.4 These are described further on the Cancer Australia website.
Following non-excisional biopsy or surgery, pathological examination of the tumour has three main aims:13
- to provide a diagnosis
- to confirm the complete removal of the lesion
- to provide extra information useful for management, such as tumour markers and hormone receptor status.
The following information can be identified through pathological examination of the excised tumour:13
- tumour size
- histological grade
- tumour margins
- presence or absence of multifocality
- the presence or absence of DCIS, both within the tumour and around it
- the presence or absence of vessel space invasion in the main tumour
- number of axillary nodes identified and examined
- extracapsular spread
- oestrogen receptor status
- progesterone receptor status.
The multidisciplinary team (MDT) would consider this information when determining treatment options for each individual.
Based on histopathology results breast cancer is categorised into the following groups:25
- pre-invasive breast cancer is confined to the milk ducts or lobules of the breast. Ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS) are types of pre-invasive breast cancer
- invasive breast cancer spreads outside the ducts or lobules of the breast into surrounding tissue.
- early breast cancer is an invasive breast cancer which is confined to the breast and axilla
- locally advanced breast cancer is the term used to describe disease spread limited to the skin, muscles, or bones of the chest
- metastatic, or advanced, breast cancer describes disease spread to other areas of the body.
Staging of the disease occurs following surgical excision and considers tumour information from the pathological report, nodal spread and metastases. Stages are numbered, ranging from zero (0) to four (IV):26
- stage 0 refers to 'pre-invasive' breast cancer
- stage I, stage IIA and stage IIB (early) refer to early breast cancer
- stage IIB, stage IIIA, stage IIIB, stage IIIC, stage IV refer to metastatic breast cancer.
- Discuss your response, and information resources that you would provide to a woman who asks you what stage IIA breast cancer means.
- Provide definitions of the following terms in the context of reporting on breast cancer:
- Tumour margins
- Extracapsular spread
- Histological grade
- Oestrogen and progesterone receptors.
Compare the likely prognosis for women diagnosed at stage IIA and stage IV.