Breast cancer occurs when abnormal cells in the breast grow out of control. Breast cancer is more common in women, but men can get it too.
Stage 2 breast cancer is cancer that is still located within the breast that is larger than 2 cm but smaller than 5 cm (about 2 inches), or the cancer has spread (metastasized) but only to nearby axillary (armpit) lymph nodes.
Stage 2 breast cancers are considered able to be cured with treatments including surgery, chemotherapy, radiation therapy, and hormonal therapy. Stage 2 breast cancer generally has a good prognosis. However, with cancer, it is not always possible to tell if any cancer cells remain in the body, which is why doctors often refer to “no evidence of disease” (NED) as remission rather than a cure.
Even if there is no evidence of disease, there is a chance breast cancer may come back (called recurrent breast cancer). Most of the time, recurrent breast cancer will occur within the first three years after treatment, though sometimes the cancer may come back years later, either locally or in distant organs in the body.
Breast cancer has a moderate risk of recurrence when all of the following apply:
- The tumor is less than 5 cm in diameter
- The cancer cells are hormone receptor positive
- The cancer is grade 1 (low grade) or grade 2 (intermediate grade)
- The cancer has spread only one to three lymph nodes
- The cancer has not spread to lymph vessels or blood vessels in the breast tissue
On average, 7 to 11 percent of women with early breast cancer may experience a local recurrence in the first five years following treatment. Patients who have a family history of breast cancer or the BRCA mutation have a higher incidence of recurrence.
What Are Symptoms of Breast Cancer?
Symptoms of breast cancer include:
- New lump in the breast
- Breast pain
- Swelling of all or part of the breast
- Skin irritation or dimpling
- Redness, scaling, flaking, or thickening of the nipple or breast skin
- Nipple pain
- Nipple turning inward
- Nipple discharge that is not breast milk
- A lump in the armpit
- A change in the size or the shape of the breast
What Causes Breast Cancer?
The specific cause of breast cancer is unknown, but it is a result of damage to a cell’s DNA.
Risk factors for developing breast cancer include:
- Age over 50 years
- Inherited genetic mutations, such as a mutation in the BRCA1 and BRCA2 genes
- Family history of breast cancer, especially a first-degree relative (mother, sister, or daughter)
- Personal history of breast cancer or noncancerous breast disease
- Having dense breasts
- Previous radiation therapy treatment to the chest or breasts
- Early onset of menstrual periods (before age 12) or late menopause (after age 55)
- History of use of the drug diethylstilbestrol (DES)
- Physical inactivity/sedentary lifestyle
How Is Breast Cancer Diagnosed?
On a physical exam, a healthcare provider may find a lump in the breast. Additional tests will be used to confirm a diagnosis, such as:
- Mammogram
- Breast ultrasound
- Magnetic resonance imaging (MRI) of the breast
- Biopsy
If the breast cancer is suspected of metastasizing imaging studies may be done to determine if the cancer has spread:
- Bone scan
- Computerized tomography (CT) scan of the chest
- CT scan of the abdomen and pelvis
- Positron emission tomography (PET) scan
What Is the Treatment for Breast Cancer?
Treatment for breast cancer depends on the extent of the tumor and may involve one or more of the following:
- Surgery
- Mastectomy
- Removal of the entire breast
- May be followed by breast reconstruction
- Lumpectomy
- Removal of the tumor and some healthy tissue that surrounds it
- Mastectomy
- Radiation therapy
- Chemotherapy
- Hormone therapy
- Targeted therapy
- Immunotherapy
From 
http://emedicine.medscape.com/article/2007112-overview
https://www.uptodate.com/contents/breast-cancer-guide-to-diagnosis-and-treatment-beyond-the-basics?search=breast%20cancer&source=search_result&selectedTitle=8~150&usage_type=default&display_rank=8
https://www.cdc.gov/cancer/breast/index.htm
https://www.ncbi.nlm.nih.gov/books/NBK61859/
https://www.cancercenter.com/cancer-types/breast-cancer/types/rare-breast-cancer-types/recurrent-breast-cancer
https://www.texasoncology.com/types-of-cancer/breast-cancer/stage-ii-breast-cancer