Stage 1, 2, 3 and 4 breast cancer: definition, management

Breast cancer is the leading incident cancer in women. Stage (or grade) of breast cancer makes it possible to define the extent of the disease. There are 5 stages: stage 0, 1, 2, 3 or 4. How do you know the stage of breast cancer? With what information? What life expectancy and what care depending on the stage?

What are the different stages of breast cancer?

There breast cancer staging allows to determine the degree of extension of the pathology. The stage is determined using the elements of the assessment at the time of diagnosis (clinical examination by the doctor, additional examinations such as mammography, ultrasound, MRI, etc.). The staging of breast cancer will make it possible to evaluate the disease at several levels:

• The local stadium: corresponds to the development of the tumor in the breast (size and infiltration)
• The regional stadium: corresponds to the extension of the disease to the level of the armpit on the same side, and therefore to the existence or not of lymph nodes affected by the disease
• The general or “remote” stage: corresponds to the extension of the disease outside the breast and the armpit, and therefore to the existence of metastasis.

From these elements, the stage of the cancer is defined according to the TNM classification (Tumor, Nodes (ganglions), Metastasis) defined by the International Union Against Cancer (UICC) and by the American Joint Committee on Cancer (AJCC).

How do you define the stage of cancer?

“The stage is important to assess the extent of the disease, but insufficient alone to determine the prognosis of the disease and therefore the necessary treatments, explains Dr Julien Seror, cancer surgeon at the Clinique St Jean de Dieu in Paris. For this, it will also be necessary to rely on the patient’s background (age, history, other pathologies, etc.) and histology (result of the biopsy), which is an essential element in the evaluation of breast cancer. This explains why the management must be done on a case-by-case basis, after having analyzed all the data, and after having discussed the files in RCP (multidisciplinary consultation meeting)“.

Depending on the extension, it will be possible to establish the “TNM” stage:

• T: the size of the tumour. Specifies whether or not the lesion is invasive (non-invasive lesions are limited to the duct or lobule, unlike invasive lesions which invade the fat around but inside the breast), as well as the size of the lesion
• N: lymph node extension. Specifies whether there is involvement of the loco-regional lymph nodes.
• M: The remote extension. Existence (M1) or not (M0) of metastases

The evaluation of the “TNM” makes it possible to determine a stage of advancement in five stages:

• Stage 0 corresponds to a cancer in situ (non-invasive).
• Stage 1 corresponds to a single tumor of small size,
• Stage 2 corresponds to a greater local invasion,
• Stage 3 corresponds to an invasion of the lymph nodes or surrounding tissues,
• Stage 4 – metastatic cancer – corresponds to a distant extension, therefore to the existence of metastasis.

What is the life expectancy according to the stage of breast cancer?

“Since 2005, the trend has been towards earlier detection, as well as improved treatment, which improves survival“says Dr. Seror.

• The age-standardized net survival at 5 years is 87% (stable) and 76% at 10 years.
• The survival rate is greater than 90% for early-stage tumors such as in situ cancers or localized breast cancers.
• Survival rate is around 80% for later stage tumorsbut without metastases.
• The life expectancy of breast cancer with metastases, on the other hand, is lower since the survival rate is 25%.

“Very few registries in France, as at the international level, provide data by cancer stage for survival analyses, concludes the specialist. Indeed, the stage is a difficult piece of data to collect routinely, and it can also be a source of error.“.

What treatment according to the stage of breast cancer?

The different treatments for treating breast cancer are determined by the stage and type of cancer. Their objectives are:

• Remove tumor or metastases
• Reduce the risk of recurrence
• Slow the development of the tumor or metastases
• Treat the symptoms caused by the disease

Sometimes one type of treatment is enough to treat breast cancer. In other cases, a combination of treatments is required. “The case of each patient must be discussed in a multidisciplinary consultation meeting (RCP), during which at least one surgeon, an oncologist and a histologist meet, and which makes it possible to determine a personalized care protocol. “, continues the doctor. The choice of the necessary treatments will be made according to:

• the patient’s background: age, associated pathologies, history of cancer and treatment…,
• the stage of the disease,
• the histological characteristics of the tumor (true identity card of the tumor, making it possible to assess the potential aggressiveness), the tumor grade (I, II or III),
• Ki 67: Index of tumor proliferation, the presence of hormone receptors, which most often implies, in case of positivity, the establishment of hormone therapy. Overexpression of the HER2 protein, which most often involves, in case of positivity, treatment with antibodies (traztuzmab, HerceptinÓ) associated with chemotherapy

When to consider surgery for breast cancer?

“This is the treatment most often used in the first instance, its objective is to remove the tissues affected by the cancer cells., says Dr. Seror. Two types of surgeries are performed: breast-conserving surgery called lumpectomy or segmentectomyand a non-conserving breast surgery called a mastectomy.

• Conservative surgery consists of removing the tumor and a small part of the tissue surrounding the tumor so that most of the patient’s breast is preserved. This surgery is preferred as soon as possible, and is supplemented by radiotherapy to avoid the risk of recurrence.
• Non-conservative surgeryis to remove the entire breast. In this case, if the patient’s condition allows it, the patient is offered breast reconstruction techniques. In some cases, it will be possible to keep the areola and the nipple.
• Armpit lymph node surgery: in the majority of cases, only the sentinel node, the first relay in the lymph node chain at the level of the armpit, is preferred. In the event of lymph node involvement, it will often be necessary to carry out an axillary dissection, that is to say, to remove the lymph node chain.

When should radiotherapy be considered for breast cancer?

Radiation therapy uses high-energy ionizing radiation. This method preserves nearby healthy tissues and organs. For breast cancer, four areas can be treated according to different cases:

• The mammary gland after conservative surgery;
• The tumor bed after conservative surgery;
• The chest wall after non-conservative surgery;
• The lymph node areas

When to consider chemotherapy?

This is a treatment administered systemically, most often intravenously, requiring the installation of a catheter for the administration of the treatment. The side effects vary according to the treatment protocols.

When to consider hormone therapy?

It is an oral treatment, in the form of tablets, taken daily for a period of 5 to 10 years. The type of treatment varies depending on the status of the patient in relation to menopause.

Thanks to Dr Julien Seror, cancer surgeon at the Clinique Saint Jean de Dieu, in Paris.