Paget's disease of the breast is a type of cancer of the breast. Treatment usually involves a lumpectomy or mastectomy to surgically remove the tumour. Chemotherapy and/or radiotherapy may be necessary, but the specific treatment often depends on the characteristics of the underlying breast cancer.

Invasive cancer or extensive ductal carcinoma "in situ" is primarily treated with modified radical mastectomies. The procedure consists in the removal of the breast, the lining over the chest muscles and a part of the lymph nodes from under the arm. In cases of noninvasive cancers, simple mastectomies are performed in which only the breast with the lining over the chest muscles is removed.

Patients suffering from cancer that has not spread beyond the nipple and the surrounding area are often treated with breast-conserving surgery or lumpectomy. They usually undergo radiation therapy after the actual procedure to prevent recurrence. A breast-conserving surgery consists in the removal of the nipple, areola and the part of the breast that is affected by cancer.

In most cases, adjuvant treatment is part of the treatment schema. This type of treatment is normally given to patients with cancer to prevent a potential recurrence of the disease. Whether adjuvant therapy is needed depends upon the type of cancer and whether the cancer cells have spread to the lymph nodes. In Paget's disease, the most common type of adjuvant therapy is radiation following breast-conservative surgery.

Adjuvant therapy may also consist of anticancer drugs or hormone therapies. Hormonal therapy reduces the production of hormones within the body, or prevents the hormones from stimulating the cancer cells to grow, and it is commonly used in cases of invasive cancer by means of drugs such as tamoxifen and anastrozole.

Most fibroadenomas are simply monitored. Some are treated by surgical excision. They are removed with a small margin of normal breast tissue if the preoperative clinical investigations are suggestive of the necessity of this procedure. A small amount of normal tissue must be removed in case the lesion turns out to be a phyllodes tumour on microscopic examination.

Because needle biopsy is often a reliable diagnostic investigation, some doctors may decide not to operate to remove the lesion, and instead opt for clinical follow-up to observe the lesion over time using clinical examination and mammography to determine the rate of growth, if any, of the lesion. A growth rate of less than sixteen percent per month in women under fifty years of age, and a growth rate of less than thirteen percent per month in women over fifty years of age have been published as safe growth rates for continued non-operative treatment and clinical observation.

Some fibroadenomas respond to treatment with ormeloxifene.

Fibroadenomas have not been shown to recur following complete excision or transform into phyllodes tumours following partial or incomplete excision.

There are different opinions on the best treatment of DCIS. Surgical removal, with or without additional radiation therapy or tamoxifen, is the recommended treatment for DCIS by the National Cancer Institute. Surgery may be either a breast-conserving lumpectomy or a mastectomy (complete or partial removal of the affected breast). If a lumpectomy is used it is often combined with radiation therapy. Tamoxifen may be used as hormonal therapy if the cells show estrogen receptor positivity. Chemotherapy is not needed for DCIS since the disease is noninvasive.

While surgery reduces the risk of subsequent cancer, many people never develop cancer even without treatment and there associated side effects. There is no evidence comparing surgery with watchful waiting and some feel watchful waiting may be a reasonable option in certain cases.

Use of radiation therapy after lumpectomy provides equivalent survival rates to mastectomy, although there is a slightly higher risk of recurrent disease in the same breast in the form of further DCIS or invasive breast cancer. Systematic reviews (including a Cochrane review) indicate that the addition of radiation therapy to lumpectomy reduces recurrence of DCIS or later onset of invasive breast cancer in comparison with breast-conserving surgery alone, without affecting mortality. The Cochrane review did not find any evidence that the radiation therapy had any long-term toxic effects. While the authors caution that longer follow-up will be required before a definitive conclusion can be reached regarding long-term toxicity, they point out that ongoing technical improvements should further restrict radiation exposure in healthy tissues. They do recommend that comprehensive information on potential side effects is given to women who receive this treatment. The addition of radiation therapy to lumpectomy appears to reduce the risk of local recurrence to approximately 12%, of which approximately half will be DCIS and half will be invasive breast cancer; the risk of recurrence is 1% for women undergoing mastectomy.

Most women with fibrocystic changes and no symptoms do not need treatment, but closer follow-up may be advised.

There is no widely accepted treatment or prevention strategy for fibrocystic condition. When treatment of symptoms is necessary it follows the same strategies as treatment for cyclical breast pain.

It is controversial whether benign breast conditions improve or worsen with oral contraceptives or hormone replacement therapy.

A few small-scale studies have indicated that the fibrocystic condition may be improved by dietary changes (especially by a reduced intake of caffeine and related methylxanthines or by a reduced intake of salt) and by vitamin supplements.

Small, preliminary studies have shown beneficial effects of iodine supplementation (such as reducing the presence of breast cysts, fibrous tissue plaques and breast pain) in women with fibrocystic breast changes, with elemental iodine (I) being more effective than iodide (I). It is noted that iodine supplementation, via an iodine-based modulation of estrogen influence in the breast, also appears to inhibit early cancer progression in small studies done on breast cancer cells in a lab.. Since treatment success in a lab is often not replicated in humans, more human research is necessary to determine if iodine supplementation prevents breast cancer

A U.S. National Institutes of Health fact sheet of 2011 reported on a randomized, double-blind, placebo-controlled clinical trial performed on 111 women affected by fibrosis and having a history of breast pain. In this trial, daily doses of iodine led to decreased in breast pain, tenderness and nodularity. It was emphasized that further research to clarify iodine's role in fibrocystic breast disease is needed and that large doses of iodine should only be used under the guidance of a physician.

The treatment for CGCG is thorough curettage. A referral is made to an oral surgeon. Recurrence ranges from 15%–20%. In aggressive tumors, three alternatives to surgery are undergoing investigation:

- corticosteroids;

- calcitonin (salmon calcitonin);

- interferon α-2a.

These therapeutic approaches provide positive possible alternatives for large lesions. The long term prognosis of giant-cell granulomas is good and metastases do not develop.

Chemotherapeutic options include:

- Cyclophosphamide plus methotrexate plus fluorouracil (CMF).

- Cyclophosphamide plus doxorubicin plus fluorouracil (CAF).

- Trastuzumab (monoclonal antibody therapy).

Hormonal options include:

- Orchiectomy.

- Gonadotropin hormone releasing hormone agonist (GNRH agonist) with or without total androgen blockage (anti-androgen).

- Tamoxifen for estrogen receptor–positive patients.

- Progesterone.

- Aromatase inhibitors.

Treatment of invasive carcinoma of no special type (NST) depends on the size of the mass (size of the tumor measured in its longest direction):

- <4 cm mass: surgery to remove the main tumor mass and to sample the lymph nodes in the axilla. The stage of the tumor is ascertained after this first surgery. Adjuvant therapy (i.e., treatment after surgery) may include a combination of chemotherapy, radiotherapy, hormonal therapy (e.g., tamoxifen) and/or targeted therapy (e.g., trastuzumab). More surgery is occasionally needed to complete the removal of the initial tumor or to remove recurrences.

- 4 cm or larger mass: modified (a less aggressive form of radical mastectomy) radical mastectomy (because any malignant mass in excess of 4 cm in size exceeds the criteria for a lumpectomy) along with sampling of the lymph nodes in the axilla.

The treatment options offered to an individual patient are determined by the form, stage and location of the cancer, and also by the age, history of prior disease and general health of the patient. Not all patients are treated the same way.

Treatment of metastatic breast cancer is currently an active area of research. Several medications are in development or in phase I/II trials. Typically new medications and treatments are first tested in metastatic cancer before trials in primary cancer are attempted.

Another area of research is finding combination treatments which provide higher efficacy with reduced toxicity and side effects.

Experimental medications:

- sorafenib a combined Tyrosine protein kinases inhibitor.

Some patients with metastatic breast cancer opt to try alternative therapies such as vitamin therapy, homeopathic treatments, a macrobiotic diet, chiropractic or acupuncture. There is no evidence that any of these therapies are effective; they may be harmful, either because patients pass up effective conventional therapies such as chemotherapy or anti-estrogen therapy in favor of alternative treatments, or because the treatments themselves are harmful (as in the case of apricot-pit therapy—which exposes the patient to cyanide—or in chiropractic, which can be dangerous to patients with cancer metastatic to the spinal bones or spinal cord. A macrobiotic diet is neither effective nor safe as it could hypothetically induce weight loss due to severe dietary restriction. There is limited evidence that acupuncture might relive pain in cancer patients, but data so far is insufficient to recommend its use outside of clinical trials.

There is free peer support and an online platform to interact with others going through various therapies, including Abraxane.

In breast cancer survivors, it is recommended to first consider non-hormonal options for menopausal effects, such as bisphosphonates or selective estrogen receptor modulators (SERMs) for osteoporosis, and vaginal estrogen for local symptoms. Observational studies of systemic hormone replacement therapy after breast cancer are generally reassuring. If hormone replacement is necessary after breast cancer, estrogen-only therapy or estrogen therapy with an intrauterine device with progestogen may be safer options than combined systemic therapy.

ADH, if found on a surgical (excisional) biopsy of a mammographic abnormality, does not require any further treatment, only mammographic follow-up.

If ADH is found on a core (needle) biopsy (a procedure which generally does not excise a suspicious mammographic abnormality), a surgical biopsy, i.e. a breast lumpectomy, to completely excise the abnormality and exclude breast cancer is the typical recommendation.

Treatment largely follows patterns that have been set for the management of postmenopausal breast cancer. The initial treatment is surgical and consists of a modified radical mastectomy with axillary dissection or lumpectomy and radiation therapy with similar treatment results as in females. Also, mastectomy with sentinel lymph node biopsy is a treatment option. In males with node-negative tumors, adjuvant therapy is applied under the same considerations as in females with node-negative breast cancer. Similarly, with node-positive tumors, males increase survival using the same adjuvants as affected females, namely both chemotherapy plus tamoxifen and other hormonal therapy. There are no controlled studies in males comparing adjuvant options. In the vast majority of males with breast cancer hormone receptor studies are positive, and those situations are typically treated with hormonal therapy.

Locally recurrent disease is treated with surgical excision or radiation therapy combined with chemotherapy. Distant metastases are treated with hormonal therapy, chemotherapy, or a combination of both. Bones can be affected either by metastasis or weakened from hormonal therapy; bisphosphonates and calcitonin may be used to counterbalance this process and strengthen bones.

Surgery has traditionally played a limited role in the treatment of IBC because it is considered essentially a systemic cancer. However, the role of surgical intervention is being reevaluated and is now considered to be an important part of the overall treatment process. The standard treatment for newly diagnosed inflammatory breast cancer is to receive systemic therapy prior to surgery. Achieving no disease in the surgical samples gives the best prognosis. Surgery is modified radical mastectomy. Lumpectomy, segmentectomy, or skin sparing mastectomy is not recommended. Immediate reconstruction is not recommended. Upfront surgery is contraindicated. After surgery, all cases are recommended for radiation therapy unless it is contraindicated.

Because the aggressive nature of the disease, it is highly recommended to be seen by IBC specialist by a multidisciplinary team.

Further, it is critical to seek novel targeted therapy in a clinical trial setting. Three modalities, surgery, chemotherapy, and radiation are under-utilized in the USA. Estrogen and Progesterone receptor positive cases have not shown to have a better prognosis. Pathological complete response to preoperative chemotherapy imparts a more favorable prognosis than a pathologically incomplete response. Loss of heterozygosity and extensive breast inflammation upon first clinical examination have a significantly worse prognosis. Premenopausal cases have significantly worse prognosis. In postmenopausal cases lean women have significantly better prognosis than obese women. Among patients with distant metastasis at diagnosis (stage IV disease), The overall survival (OS) is worse in patients with IBC than in those with non-IBC.

Breast cysts do not require treatment unless a cyst is large and painful or otherwise uncomfortable. In that case, draining the fluid from a breast cyst can ease symptoms.

Typical treatment involves a Needle aspiration biopsy. Aspirated cysts often recur (come back); definitive treatment may require surgery.

Draining the fluid and then waiting for the cyst to resolve is the main treatment applied in these cases. Moreover, if cysts are aspirated and the fluid looks normal, they do not require any other medical attention apart from following-up to make sure they have completely disappeared. Hormone therapy, by the means of oral contraceptives, is sometimes prescribed to reduce their recurrence and to regulate the menstrual cycle of the patient (which is likely to cause them in the first place). Danazol may also be prescribed to treat this condition and it is usually considered in patients on whom the non-medical treatment fails and the symptoms are intense.

Surgical removal of a breast cyst is necessary only in a few unusual circumstances. If an uncomfortable breast cyst recurs month after month, or if a breast cyst contains blood-tinged fluid and displays other worrisome signs, surgery may be considered.

In breast cancer survivors, non-hormonal birth control methods should be used as first-line options. Progestogen-based methods such as depot medroxyprogesterone acetate, IUD with progestogen or progestogen only pills have a poorly investigated but possible increased risk of cancer recurrence, but may be used if positive effects outweigh this possible risk.

The FDA has approved cryoablation of a fibroadenoma as a safe, effective and minimally-invasive alternative to open surgical removal in 2001. In the procedure, ultrasound imaging is used to guide a probe into the mass of breast tissue. Extremely cold temperatures are then used to destroy the abnormal cells, and over time the cells are reabsorbed into the body. The procedure can be performed as an outpatient surgery using local anesthesia only, and leaves substantially less scarring than open surgical procedures and no breast tissue deformation.

The American Society of Breast Surgeons recommends the following criteria to establish a patient as a candidate for cryoablation of a fibroadenoma:

1. The lesion must be sonographically visible.

2. The diagnosis of a fibroadenoma must be confirmed histologically.

3. The lesion should be less than 4 cm in diameter.

There are usually no adverse side effects to this condition. In almost all cases it subsides after menopause. A possible complication arises through the fact that cancerous tumors may be more difficult to detect in women with fibrocystic changes.

The presence of three factors for the prognosis has been suggested, whether there is a palpable mass of the disease, whether lymph nodes are positive and whether there is an underlying malignant cancer.

If there is none of these, the five- and 10-year survival is 85% and 80% respectively, with adjuvant chemotherapy even 95% and 90%. If there is a palpable mass, it is 32% and 31% respectively, with adjuvant chemotherapy (40% and 35%).

Positive lymph-nodes have been positively associated with a palpable mass and affect the prognosis to be now just 28% survival after 10 years (vs 79% without palpable mass and without affected lymph-nodes). Involvement of the lymph nodes does not directly cause any harm, but is merely an indicator of systemic spread.

Furthermore, patients with an identifiable associated underlying breast tumor have a survival rate of 38-40% at five years and a survival rate of 22-33% at 10 years. The death rate of metastatic breast carcinoma in patients with mammary Paget's disease and underlying cancer is 61.3%, with a 10-year cumulative survival rate of 33%.

Angiogenesis and EGFR (HER-1) inhibitors are frequently tested in experimental settings and have shown efficacy. Treatment modalities are not sufficiently established for normal use, and it is unclear in which stage they are best used and which patients would profit.

By 2009 A number of new strategies for TNBC were being tested in clinical trials, including the PARP inhibitor BSI 201, NK012.

A novel antibody-drug conjugate known as Glembatumumab vedotin (CDX-011), which targets the protein GPNMB, has also shown encouraging clinical trial results in 2009.

PARP inhibitors had shown some promise in early trials but failed in some later trials.

Nov 2013: An accelerated approval Phase II clinical trial (METRIC) investigating glembatumumab vedotin versus capecitabine has begun, expected to enroll 300 patients with GPNMB-expressing metastatic TNBC.

Three early stage trials reported TNBC results in June 2016, for IMMU-132, Vantictumab, and atezolizumab in combination with the chemotherapy nab-paclitaxel.

General treatment regimens have not changed much in the past 30 years, in part due to the lack of randomized clinical trials. Surgery is the treatment of choice if the tumor is determined to be resectable. Curettage is a commonly used technique. The situation is complicated in a patient with a pathological fracture. It may be best to immobilize the affected limb and wait for the fracture to heal before performing surgery.

Patients with tumors that are not amenable to surgery are treated with radiation therapy. However caution is employed since a majority of recurrent tumors with transformations to the malignant sarcoma phenotype have been in patients receiving radiotherapy for their primary benign lesion. Pharmacotherapy for GCTOB, includes bisphosphonates such as Zoledronate, which are thought to induce apoptosis in the MNGC fraction, preventing tumor-induced osteolysis. Indeed, "in vitro" studies have shown zolidronate to be effective in killing osteoclast-like cells. More recently, humanized monoclonal antibodies such as Denosumab targeting the RANK ligand have been employed in treatment of GCTOB in a phase II study. This is based on the notion that increased expression of RANK-ligands by stromal cells plays a role in tumor pathogenesis.

The presence of a radial scar on imaging mandates a percutaneous core biopsy for histologic diagnosis. Excisional biopsy is usually recommended for radial scar, although it has been argued that core biopsy evaluation and surveillance may be appropriate in selected patients.

Treatment protocol is not well established. Some sources report that approximately half of the patients will fully recover after lengthy (mean time 14.5 months, range 2–24 months) expectant management.

Treatment with steroids is lengthy and usually requires about 6 months. While some source report very good success with steroids most report a considerable risk of recurrence after a treatment with steroids alone. Steroids are known to cause elevation of prolactin levels and increase risk of several conditions such as diabetes, and other endocrinopathies which in turn increase the risk of IGM. Treatment with topical steroids to limit side effects was also reported in one case. For surgical treatment recurrence rates of 5-50% have been reported.

A 1997 literature review article recommended complete resection or corticosteroid therapy, stating also that long-term follow-up was indicated due to a high rate of recurrence.

Treatment with a combination of glucocorticoids and prolactin lowering medications such as bromocriptine or cabergoline was used with good success in Germany. Prolactin lowering medication has also been reported to reduce the risk of recurrence. In cases of drug-induced hyperprolactinemia (such as antipsychotics) prolactin-sparing medication can be tried.

Methotrexate alone or in combination with steroids has been used with good success. Its principal mechanism of action is immunomodulating activity, with a side effect profile that is more favorable for treating IGM.

Colchicine, azathioprine and NSAIDs have also been used.

Standard treatment is surgery with adjuvant chemotherapy and radiotherapy. As a variation, neoadjuvant chemotherapy is very frequently used for triple-negative breast cancers. This allows for a higher rate of breast-conserving surgeries and by evaluating the response to the chemotherapy gives important clues about the individual responsiveness of the particular cancer to chemotherapy.

In addition to chemotherapy, an additive called Didox can be added to aid in the reduction of drug resistance and further treatment efforts. Didox is used to inhibit ribonucleotide reductase M2 (RRM2) which contributes to the cells resistance of the chemotherapy treatment resulting in a large number of relapse (Wilson 2016). RRM2 is upregulated within these specific Triple Negative cancer cells leading to a higher rate of drug resistance and inability to slow or stop the tumor progression which leads to more aggressive forms of triple negative breast cancer that are often fatal (Wilson 2016).

TNBCs are generally very susceptible to chemotherapy. In some cases, however, early complete response does not correlate with overall survival. This makes it particularly complicated to find the optimal chemotherapy. Adding a taxane to the chemotherapy appears to improve outcome substantially.

"BRCA1"-related triple-negative breast cancer appear to be particularly susceptible to chemotherapy including platinum-based agents and taxanes.

Although mutations in single genes were not individually predictive, TNBC tumors bearing mutations in genes involved in the androgen receptor (AR) and FOXA1 pathways were much more sensitive to chemotherapy. Mutations in the AR/FOXA1 pathway provide a novel marker for identifying chemosensitive TNBC patients who may benefit from current standard-of-care chemotherapy regimens. Mutations that lowered the levels of functional BRCA1 or BRCA2 RNA were associated with significantly better survival outcomes. This BRCA deficience signature define a new, highly chemosensitive subtype of TNBC. BRCA-deficient TNBC tumors have a higher rate of clonal mutation burden, defined as more clonal tumors with a higher number of mutations per clone, and are also associated with a higher level of immune activation, which may explain their greater chemosensitivity.

Treatment is by surgical excision (complete removal) of the fibrous tissue overgrowth and addressing the causative factor to prevent recurrence of the lesion. Other sources suggest that surgical excision may not be required in all cases. Common techniques for removal of the excess tissue include traditional removal with a surgical scalpel, electrical scalpel, or laser excision with a laser scalpel, e.g. a carbon dioxide laser, , Neodymium-YAG laser, or diode laser. The poorly fitting denture can be adapted to fit better (a "reline") or a new denture constructed. Alternatively, the section of flange that is sharp/over-extended can be smoothed and reduced with a drill.