Lymphoma in the breast, also known as primary breast lymphoma, is a rare type of non-Hodgkin lymphoma that starts in the breast tissue. Non-Hodgkin lymphoma is a cancer that begins in the white blood cells called lymphocytes, which help fight infection. When lymphocytes grow out of control, they can form tumors or cancerous cells. Lymphoma most often begins in the lymph nodes, but in rare cases like primary breast lymphoma, it starts in other parts of the body like the breast.
Primary breast lymphoma represents about 0.04-0.5% of all breast cancers. It can occur at any age but is more common in older women, with a median age at diagnosis of 60-70 years old. Women with primary breast lymphoma may notice a lump in the breast or experience breast swelling and pain. Some women do not have any symptoms. Evaluation typically includes breast imaging like mammogram or ultrasound as well as a biopsy to confirm the diagnosis.
Primary breast lymphoma is considered potentially curable depending on the subtype and stage at diagnosis. Treatment usually involves chemotherapy with or without radiation. The 5-year overall survival rate is reported between 40-73%, indicating that a significant proportion of patients can remain in remission long-term after treatment.
What is lymphoma?
Lymphoma refers to cancers that arise from lymphocytes, a type of white blood cell. There are two main categories of lymphoma:
– Hodgkin lymphoma – Named after Dr. Thomas Hodgkin, who first characterized it. This type of lymphoma spreads in an orderly manner from one lymph node group to another. Around 10% of all lymphomas are Hodgkin lymphomas.
– Non-Hodgkin lymphoma – A diverse group of lymphomas that do not follow the orderly spread seen in Hodgkin lymphoma. Around 90% of lymphomas are non-Hodgkin.
Non-Hodgkin lymphomas can start in lymph nodes or outside of the lymphatic system in organs like the stomach, skin, or breast.
Lymphocytes normally work to fight infections. In lymphoma, lymphocytes grow abnormally and form collections of cells called tumors. These lymphoma tumors are typically malignant, meaning they can grow aggressively and spread to other parts of the body.
Lymphoma develops when lymphocytes go through mutations in their DNA that cause them to multiply quickly and live longer than normal cells. The specific reason why a normal lymphocyte becomes a malignant lymphoma cell is not well understood.
There are over 60 different subtypes of non-Hodgkin lymphoma, all arising from different types of lymphocytes. The most common forms of non-Hodgkin lymphoma include:
– Diffuse large B-cell lymphoma – Starts in B lymphocytes and makes up about 40% of non-Hodgkin lymphomas.
– Follicular lymphoma – Starts in B lymphocytes and represents about 20% of cases.
– Marginal zone B-cell lymphoma – Starts in B lymphocytes and makes up about 10% of lymphomas.
– Mantle cell lymphoma – Starts in B lymphocytes and accounts for 5-10% of cases.
– T-cell lymphomas – Start in T lymphocytes and include subtypes like anaplastic large cell lymphoma.
What is lymphoma of the breast?
Lymphoma of the breast, also called primary breast lymphoma, is when lymphoma arises within the breast tissue rather than spreading from elsewhere. Breast lymphoma is rare, accounting for less than 1% of breast tumors and only about 0.5% of all lymphomas.
Non-Hodgkin lymphoma subtypes are the most common forms of breast lymphoma. Diffuse large B-cell lymphoma is the most common subtype in the breast, making up 45-75% of cases. Other subtypes like follicular, marginal zone, and mantle cell lymphoma can also arise as primary breast lymphomas. T-cell lymphomas in the breast are very rare.
Women are much more commonly affected by breast lymphoma compared to men. The typical age at diagnosis is in the 60s, but cases can occur in younger women as well. For unknown reasons, the right breast is more often involved than the left. Around 12-37% of patients have both breasts affected at diagnosis.
Some key facts about primary breast lymphoma:
– Represents 0.04% to 0.5% of breast cancers
– 45-75% are diffuse large B-cell lymphoma
– More common in women and the right breast
– Median age at diagnosis 60-70 years
– Can involve one or both breasts
Breast lymphoma needs to be distinguished from secondary breast lymphoma, where lymphoma that started elsewhere spreads to the breast later. Primary breast lymphoma starts in the breast tissue itself rather than spreading from distant lymph nodes or organs. Identifying breast lymphoma as primary versus secondary has implications for staging and prognosis.
What causes breast lymphoma?
The cause of breast lymphoma is not fully understood. As with lymphomas that arise in lymph nodes, it develops due to genetic changes that cause lymphocytes in the breast tissue to proliferate abnormally and form malignant cells.
There are some risk factors that are thought to increase the odds of developing breast lymphoma:
– Age – Risk increases as women get older. Most cases occur in women over 50.
– Family history – Having a first-degree relative with lymphoma can raise risk.
– Breast implants – Some research indicates women with breast implants have a higher risk of developing anaplastic large cell lymphoma in the breast.
– Autoimmune disease – Diseases like Sjögren’s syndrome and rheumatoid arthritis appear to predispose to lymphoma.
– Immunodeficiency – HIV/AIDS, organ transplantation, and other conditions causing low immunity can increase lymphoma risk.
– Radiation exposure – Prior radiation to the chest for other cancers may be a risk factor.
– Chemical exposures – Certain herbicides and chemicals have been associated with higher lymphoma risk.
However, most women with breast lymphoma do not have any known risk factors or predisposing medical conditions. More research is needed to determine if avoiding these risk factors reduces the chances of developing breast lymphoma for the average woman.
What are the symptoms of breast lymphoma?
The most common symptom that brings a woman with breast lymphoma to medical attention is finding a breast lump. Around 85% of women with breast lymphoma report noticing a distinct palpable lump in the breast. Sometimes there are multiple lumps rather than just one dominant mass.
Other possible signs and symptoms of primary breast lymphoma include:
– Non-painful breast swelling – The breast may become visibly enlarged.
– Breast pain – Some women have painful breasts.
– Nipple discharge – An unusual discharge may be noticed coming from the nipple. Discharge is often clear or bloody.
– Redness and warmth – The breast may become red, warm, inflamed, or itchy resembling an infection.
– Skin changes – Thickening, abnormal pigmentation, or puckering of the breast skin.
– No symptoms – Up to 25% of patients with breast lymphoma report no symptoms at all. The lymphoma is often detected by screening mammograms.
Breast lymphoma typically does not cause systemic symptoms such as weight loss, fevers, or night sweats in early stages. However, advanced breast lymphoma can spread to locations like the bone marrow leading to fatigue and other symptoms.
Since breast swelling, pain, and lumps have many potential benign causes, breast lymphoma is often initially suspected to be another condition like breast infection or a benign cyst. Breast imaging and biopsy are needed to establish the diagnosis conclusively.
How is breast lymphoma diagnosed?
If breast lymphoma is suspected based on signs and symptoms, the following tests will be performed to confirm the diagnosis:
– Breast exam – Feeling carefully along all regions of the breast and underarms for any palpable lumps or abnormalities.
– Imaging tests – Mammogram, ultrasound, and/or breast MRI to identify any breast masses and see their characteristics. Breast imaging can’t conclusively diagnose lymphoma but provides clues.
– Biopsy – The key diagnostic test is a biopsy, where some breast tissue is extracted and examined under the microscope. This allows doctors to definitively identify lymphoma cells.
– Blood tests – General blood tests and tests to evaluate liver/kidney function may be done.
– Bone marrow biopsy – Used to see if the lymphoma has spread to the bone marrow.
– PET/CT scan – A positron emission tomography (PET) scan combined with a CT scan can help stage the lymphoma by finding areas of involvement beyond the breast.
– Cardiac workup – Some screening tests before chemotherapy may assess heart function.
The biopsy of the breast mass provides the most important information by identifying the subtype of lymphoma cells and whether they are fast or slow growing.
Doctors also do tests to stage the lymphoma, which determines if it is localized to the breast or has spread elsewhere in the body. Staging helps predict prognosis and guide treatment.
How is breast lymphoma staged?
Once breast lymphoma is diagnosed, imaging and testing are done to stage the disease from stage I through IV:
– **Stage I** – The lymphoma is localized to one breast only. It involves a single lymph node region on the same side as the affected breast.
– **Stage II** – The lymphoma is in both breasts, but not yet beyond the breast/chest region. It involves lymph nodes on both sides of the chest.
– **Stage III** – The lymphoma has spread from the breast(s) to lymph nodes above and below the collar bone, and/or to the armpit, chest wall, or sternum.
– **Stage IV** – The most advanced stage where the lymphoma is metastatic beyond the breast and nearby lymph nodes. It involves organs like the bones, liver, or lungs.
Stage I or II where the lymphoma cells are limited to the breasts and nearby lymph nodes are more favorable. Stage III disease that has spread to numerous lymph nodes above the collar bone or lower chest is more concerning. Stage IV metastatic breast lymphoma has the poorest prognosis.
How is breast lymphoma treated?
Most patients with localized breast lymphoma receive a combination of chemotherapy and radiation:
– **Chemotherapy** – Using drugs to kill and shrink the cancer cells. The most common regimen uses a combination of drugs called CHOP – cyclophosphamide, doxorubicin, vincristine, and prednisone. Other combinations may be used as well. Chemotherapy is typically given in cycles with rest periods between.
– **Radiation** – High energy beams targeted at the affected breast and regional lymph nodes to destroy cancerous cells. Radiation is often started after a few cycles of chemo when the tumor burden has reduced.
– **Surgery** – Surgery was previously done to remove the breast lymphoma, but is now rarely needed with chemotherapy and radiation. A biopsy may still be done to diagnose breast lymphoma.
Other therapies sometimes used include:
– **Stem cell transplant** – Used for fit patients with aggressive fast-growing lymphoma that carries a poor prognosis with chemotherapy alone. High dose chemotherapy is given with stem cell rescue.
– **Monoclonal antibodies** – Drugs like rituximab that target proteins on lymphoma cells can enhance chemotherapy effectiveness.
– **Immunotherapy** – Drugs that boost the immune response against lymphoma may be used in some situations.
For non-localized advanced stage breast lymphomas, treatment also needs to manage disease that has spread beyond the breast using systemic chemotherapy. Radiation can help shrink unresectable tumors causing symptoms. Palliative radiation or surgery may also be used to treat problematic metastatic lesions in bones, the brain, or other organs.
What is the prognosis for breast lymphoma?
The outlook and survival rates for breast lymphoma depend on several factors:
– **Stage** – Early stage I/II disease where the lymphoma is confined to the breasts and nearby nodes has a better prognosis than advanced stage III/IV disease. 5-year survival is over 90% for stage I but only around 45% for stage IV disease.
– **Subtype** – Slow growing subtypes like follicular lymphoma have better outcomes. Diffuse large B-cell lymphoma is more aggressive. T-cell breast lymphomas behave most aggressively.
– **Age** – Younger patients typically respond better to chemotherapy drugs.
– **Treatment response** – Patients who achieve a complete response to initial chemotherapy and radiation do better than those with resistant or relapsed lymphoma.
Overall survival statistics for primary breast lymphoma:
– 5-year overall survival: 40-73%
– 10-year overall survival: 54-65%
With modern treatments combining chemotherapy regimens like CHOP with involved field radiation, 40-75% of patients with breast lymphoma survive long term without disease progression. The prognosis is especially favorable if the disease is diagnosed at an early stage while still localized to the breasts. Being disease-free and off treatment for 5 years is generally considered cured. However, relapses even after prolonged remission are still possible later.
What is the follow up care after breast lymphoma treatment?
After completing lymphoma treatment, patients need continued follow up to monitor for potential recurrence:
– **Physical exams** – Examination of the breasts and lymph nodes every 3-6 months for the first couple years, then decreasing in frequency. Report any new lumps or swelling.
– **Blood tests** – Certain blood tests may be done to help detect relapse early. Testing is typically done every 6 months.
– **Imaging** – CT scans or PET/CT scans every 6 months at first to monitor for recurrence or spread. Repeated less frequently long term.
– **Mammograms** – Yearly screening mammograms recommended to look for new tumors in remaining breast tissue. Specific timing of mammograms will depend on the treatment received.
It’s important to keep all follow up appointments even when feeling well. Reporting concerning symptoms in between visits is also recommended, as prompt evaluation of potential relapse improves outcomes. Routine screening for second cancers should continue too, like cervical, colon, and skin cancer screening.
The risk of breast lymphoma coming back decreases over time, but late relapses after many years are not uncommon. Lifelong monitoring by both an oncologist and primary care provider is ideal. Maintaining a healthy lifestyle may also help prevent recurrences.
Conclusion
In summary, primary breast lymphoma is a rare type of non-Hodgkin lymphoma arising in the breast tissue. It most commonly affects older women and presents as a painless breast mass. Diagnosis is made by biopsy. Treatment involves chemotherapy such as CHOP combined with radiation to the breast and regional nodes. Localized breast lymphoma generally has a favorable prognosis with 40-75% long term survival reported. However, recurrences even after prolonged remission are possible. Ongoing follow up care and surveillance for relapse are important after finishing lymphoma therapy.