When an individual is diagnosed with cancer, the first course of action is to determine what stage the cancer is at. This information will enable the medical team to determine what course of treatment would work best and what steps should immediately be taken to increase the efficacy of treatments. In the case of breast cancer, the more the cancerous cells have spread, the more intensive the treatment will be. As the chances of successfully treating cancer reduce as the disease progresses, it is crucial to detect it at an early stage. The common treatments required for breast cancer are as follows:

• Stage 0: In this stage, cancer is still limited to the milk ducts and is still non-invasive. Due to this, the treatment that will be carried out is different from the treatment which will be used for an invasive type of cancer.
  A breast tumor at stage 0 is known as Ductal Carcinoma In Situ (DCIS). DCIS usually does not spread outside the breast. It isn’t life-threatening but it does lead to a greater risk of developing invasive breast cancer. For the treatment of DCIS, one can go about a breast-conserving surgery or a simple mastectomy. The latter can be a better option in some cases.
• Stage 1: In this stage, cancer has not yet spread out or has invaded only a small portion of the sentinel lymph node. So, the nearby lymph nodes will need to be checked either with an axillary lymph node dissection (ALND) or a sentinel lymph node biopsy (SLNB). At this stage, however, the main treatment option is surgery. This surgery can either take the form of breast-conserving surgery or a mastectomy. Radiation therapy can be suggested after the surgery in some cases to reduce the chance of recurrence.
• Stage 2: In this stage, the situation has advanced and cancer has already invaded a few lymph nodes nearby. This stage is treated either with a lumpectomy/partial mastectomy or mastectomy. Similar to the previous stage, the nearby lymph nodes would have to be checked either with an SLNB or an ALND. Patients diagnosed with cancer in some lymph nodes through the SLNB will only have the affected lymph nodes removed. For the rest of the lymph nodes, radiation therapy might be suggested following the mastectomy.
• Stage 3: In this stage, the tumor is larger than 5 cm. More often than not, the go-to treatment option for this stage is neoadjuvant chemotherapy. Based on whether the tumor shrinks through medication and chemotherapy, a mastectomy is done if the tumor doesn’t shrink and breast-conserving surgery if it does.
• Stage 4: Cancer has spread through the whole breast, to the lymph nodes, and also to other parts of the body. Systemic drug therapies constitute the major treatment options for this stage and the focus is on managing the disease rather than curing it completely as cancer may be terminal in most cases. Common treatments for breast cancer include targeted drugs, hormone therapy, immunotherapy, chemotherapy, or a combination of these.