There is no standard therapy for multicentric Castleman disease. Treatment modalities change based on HHV-8 status, so it is essential to determine HHV-8 status before beginning treatment. For HHV-8-associated MCD the following treatments have been used: rituximab, antiviral medications such as ganciclovir, and chemotherapy.

Treatment with the antiherpesvirus medication ganciclovir or the anti-CD20 B cell monoclonal antibody, rituximab, may markedly improve outcomes. These medications target and kill B cells via the B cell specific CD20 marker. Since B cells are required for the production of antibodies, the body's immune response is weakened whilst on treatment and the risk of further viral or bacterial infection is increased. Due to the uncommon nature of the condition there are not many large scale research studies from which standardized approaches to therapy may be drawn, and the extant case studies of individuals or small cohorts should be read with caution. As with many diseases, the patient's age, physical state and previous medical history with respect to infections may impact the disease progression and outcome.

For HHV-8-negative MCD (idiopathic MCD), the following treatments have been used: corticosteroids, rituximab, monoclonal antibodies against IL-6 such as tocilizumab and siltuximab, and the immunomodulator thalidomide.

Prior to 1996 MCD carried a poor prognosis of about 2 years, due to autoimmune hemolytic anemia and non-Hodgkin's lymphoma which may arise as a result of proliferation of infected cells. The timing of diagnosis, with particular attention to the difficulty of determining the cause of B symptoms without a CT scan and lymph node biopsy, may have a significant impact on the prognosis and risk of death. Left untreated, MCD usually gets worse and becomes increasingly difficult and unresponsive to current treatment regimens.

Siltuximab prevents it from binding to the IL-6 receptor, was approved by the U.S. Food and Drug Administration for the treatment of multicentric Castleman disease on April 23, 2014. Preliminary data suggest that treatment siltuximab may achieve tumour and symptomatic response in 34% of patients with MCD.

Other treatments for multicentric Castleman disease include the following:

- Corticosteroids

- Chemotherapy

- Thalidomide

Some patients have no symptoms, spontaneous remission, or a relapsing/remitting course, making it difficult to decide whether therapy is needed. In 2002, authors from Sapienza University of Rome stated on the basis of a comprehensive literature review that "clinical observation without treatment is advisable when possible."

Therapeutic options include surgery, radiation therapy, and chemotherapy. Surgery is used to remove single lymph nodes, central nervous system lesions, or localized cutaneous disease. In 2014, Dalia and colleagues wrote that for patients with extensive or systemic Rosai–Dorfman disease, "a standard of care has not been established" concerning radiotherapy and chemotherapy.

Breast implant-associated ALCL is a recently recognized lymphoma and definitive management and therapy is under evaluation. However, it appears that removal of the implant, and resection of the capsule around the implant as well as evaluation by medical and surgical oncologists are cornerstones. Still under evaluation is the extent of capsulectomy: partial versus complete capsulectomy; similarly it is not defined the significance of replacement of the implant in the affected breast, or the removal of contralateral implant. Similarly, the value of radiation therapy and chemotherapy are under evaluation.

Currently, there is a drug, LDK378, undergoing Phase III clinical trials at Vanderbilt University that targets ALK positive small cell lung cancer, and has showed clinical promise in its previous clinical trials. Because approximately 70% of ALCL neoplasms are also ALK positive, there is hope that similar highly selective and potent ALK inhibitors may be used in the future to treat ALK positive cases of ALCL.

An example antibody for use in immunotherapy is Rituximab. Rituximab has specific use in treatment of NLPHL as it is a chimeric monoclonal antibody against the protein CD20. Studies indicate Rituximab offers potential in relapsed or refractory patients, and also in front-line treatment especially in advanced stages. Because of a tendency for relapse, maintenance treatment such as every 6 months for 2 years is suggested. Rituximab has been shown to improve patient outcomes after histological transformation.

Possible options such as anthracycline-containing regimens include ABVD, BEACOPP and CHOP. Results of a trial with COPP/ABV in children suggested positive results with chemotherapy alone are possible without the need for radiation therapy. Optimal chemotherapy is a topic for debate, for example there is evidence of support for treatment with R-CHOP instead of ABVD, results showing high rates (40%) of relapse after 10 years since ABVD chemotherapy. BEACOPP has higher reported toxicity risk.

Patients with early stage disease (IA or IIA) are effectively treated with radiation therapy or chemotherapy. The choice of treatment depends on the age, sex, bulk and the histological subtype of the disease. Adding localised radiation therapy after the chemotherapy regimen may provide a longer progression-free survival compared with chemotherapy treatment alone. Patients with later disease (III, IVA, or IVB) are treated with combination chemotherapy alone. Patients of any stage with a large mass in the chest are usually treated with combined chemotherapy and radiation therapy.

It should be noted that the common non-Hodgkin's treatment, rituximab (which is a monoclonal antibody against CD20) is not routinely used to treat Hodgkin's lymphoma due to the lack of CD20 surface antigens in most cases. The use of rituximab in Hodgkin's lymphoma, including the lymphocyte predominant subtype has been recently reviewed.

Although increased age is an adverse risk factor for Hodgkin's lymphoma, in general elderly patients without major comorbidities are sufficiently fit to tolerate standard therapy, and have a treatment outcome comparable to that of younger patients. However, the disease is a different entity in older patients and different considerations enter into treatment decisions.

For Hodgkin's lymphomas, radiation oncologists typically use external beam radiation therapy (sometimes shortened to EBRT or XRT). Radiation oncologists deliver external beam radiation therapy to the lymphoma from a machine called linear accelerator which produces high energy X Rays and Electrons. Patients usually describe treatments as painless and similar to getting an X-ray. Treatments last less than 30 minutes each.

For lymphomas, there are a few different ways radiation oncologists target the cancer cells. Involved field radiation is when the radiation oncologists give radiation only to those parts of the patient's body known to have the cancer. Very often, this is combined with chemotherapy. Radiation therapy directed above the diaphragm to the neck, chest or underarms is called mantle field radiation. Radiation to below the diaphragm to the abdomen, spleen or pelvis is called inverted-Y field radiation. Total nodal irradiation is when the therapist gives radiation to all the lymph nodes in the body to destroy cells that may have spread.

The high cure rates and long survival of many patients with Hodgkin's lymphoma has led to a high concern with late adverse effects of treatment, including cardiovascular disease and second malignancies such as acute leukemias, lymphomas, and solid tumors within the radiation therapy field. Most patients with early-stage disease are now treated with abbreviated chemotherapy and involved-field radiation therapy rather than with radiation therapy alone. Clinical research strategies are exploring reduction of the duration of chemotherapy and dose and volume of radiation therapy in an attempt to reduce late morbidity and mortality of treatment while maintaining high cure rates. Hospitals are also treating those who respond quickly to chemotherapy with no radiation.

In childhood cases of Hodgkin's lymphoma, long-term endocrine adverse effects are a major concern, mainly gonadal dysfunction and growth retardation. Gonadal dysfunction seems to be the most severe endocrine long-term effect, especially after treatment with alkylating agents or pelvic radiotherapy.

Treatment of some other, more aggressive, forms of lymphoma can result in a cure in the majority of cases, but the prognosis for patients with a poor response to therapy is worse. Treatment for these types of lymphoma typically consists of aggressive chemotherapy, including the CHOP or R-CHOP regimen. A number of people are cured with first-line chemotherapy. Most relapses occur within the first two years, and the relapse risk drops significantly thereafter. For people who relapse, high-dose chemotherapy followed by autologous stem cell transplantation is a proven approach.

Due to the high risk of recurrence and ensuing problems, close monitoring of dogs undergoing chemotherapy is important. The same is true for dogs that have entered remission and ceased treatment. Monitoring for disease and remission/recurrence is usually performed by palpation of peripheral lymph nodes. This procedure detects gross changes in peripheral lymph nodes. Some of the blood tests used in diagnosing lymphoma also offer greater objectivity and provide an earlier warning of an animal coming out of remission.

Complete cure is rare with lymphoma and treatment tends to be palliative, but long remission times are possible with chemotherapy. With effective protocols, average first remission times are 6 to 8 months. Second remissions are shorter and harder to accomplish. Average survival is 9 to 12 months. The most common treatment is a combination of cyclophosphamide, vincristine, prednisone, L-asparaginase, and doxorubicin. Other chemotherapy drugs such as chlorambucil, lomustine (CCNU), cytosine arabinoside, and mitoxantrone are sometimes used in the treatment of lymphoma by themselves or in substitution for other drugs. In most cases, appropriate treatment protocols cause few side effects, but white blood cell counts must be monitored.

Allogeneic and autologous stem cell transplantations (as is commonly done in humans) have recently been shown to be a possible treatment option for dogs. Most of the basic research on transplantation biology was generated in dogs. Current cure rates using stem cell therapy in dogs approximates that achieved in humans, 40-50%.

When cost is a factor, prednisone used alone can improve the symptoms dramatically, but it does not significantly affect the survival rate. The average survival times of dogs treated with prednisone and untreated dogs are both one to two months. Using prednisone alone can cause the cancer to become resistant to other chemotherapy agents, so it should only be used if more aggressive treatment is not an option.

Isotretinoin can be used to treat cutaneous lymphoma.

Chemotherapy is widely used as frontline treatment, and often is not repeated in relapse due to side effects. Alternate chemotherapy is sometimes used at first relapse. For frontline treatment, CHOP with rituximab is the most common chemotherapy, and often given as outpatient by IV. A stronger chemotherapy with greater side effects (mostly hematologic) is HyperCVAD, often given as in-patient, with rituximab and generally to fitter patients (some of which are over 65). HyperCVAD is becoming popular and showing promising results, especially with rituximab. It can be used on some elderly (over 65) patients, but seems only beneficial when the baseline Beta-2-MG blood test was normal. It is showing better complete remissions (CR) and progression free survival (PFS) than CHOP regimens. A less intensive option is bendamustine with rituximab.

Second line treatment may include fludarabine, combined with cyclophosphamide and/or mitoxantrone, usually with rituximab. Cladribine and clofarabine are two other drugs being investigated in MCL. A relatively new regimen that uses old drugs is PEP-C, which includes relatively small, daily doses of prednisone, etoposide, procarbazine, and cyclophosphamide, taken orally, has proven effective for relapsed patients. According to John Leonard, PEP-C may have anti-angiogenetic properties, something that he and his colleagues are testing through an ongoing drug trial.

Another approach involves using very high doses of chemotherapy, sometimes combined with total body irradiation (TBI), in an attempt to destroy all evidence of the disease. The downside to this is the destruction of the patients' entire immune system as well, requiring rescue by transplantation of a new immune system (hematopoietic stem cell transplantation), using either autologous stem cell transplantation, or those from a matched donor (an allogeneic stem cell transplant). A presentation at the December 2007 American Society of Hematology (ASH) conference by Christian Geisler, chairman of the Nordic Lymphoma Group claimed that according to trial results, mantle cell lymphoma is potentially curable with very intensive chemo-immunotherapy followed by a stem cell transplant, when treated upon first presentation of the disease.

These results seem to be confirmed by a large trial of the European Mantle Cell Lymphoma Network indicating that induction regimens containing monoclonal antibodies and high dose ARA-C (Cytarabine) followed by ASCT should become the new standard of care of MCL patients up to approximately 65 years.

A study released in April 2013 showed that patients with previously untreated indolent lymphoma, bendamustine plus rituximab can be considered as a preferred first-line treatment approach to R-CHOP because of increased progression-free survival and fewer toxic effects.

In November 2013, ibrutinib was approved by the US FDA for treating MCL.

Other targeted agents include the proteasome inhibitor bortezomib, mTOR inhibitors such as temsirolimus, and the P110δ inhibitor GS-1101.

Many low-grade lymphomas remain indolent for many years. Treatment of the nonsymptomatic patient is often avoided. In these forms of lymphoma, such as follicular lymphoma, watchful waiting is often the initial course of action. This is carried out because the harms and risks of treatment outweigh the benefits. If a low-grade lymphoma is becoming symptomatic, radiotherapy or chemotherapy are the treatments of choice; although they do not cure the lymphoma, they can alleviate the symptoms, particularly painful lymphadenopathy. Patients with these types of lymphoma can live near-normal lifespans, but the disease is incurable. Some centers advocate the use of single agent rituximab in the treatment of follicular lymphoma rather than the wait and watch approach. Watchful waiting is not a good strategy for all patients, as it leads to significant distress and anxiety in some patients. It has been equated with watch and worry.

One such development is in the delivery of doxorubicin. While it is an effective inducer of apoptosis, doxorubicin is quickly filtered out of the body. By loading a PEG-liposome with doxorubicin the circulation time and localization to tumors greatly increases. Cancerous tumors characteristically have extensive angiogenesis and leaky vasculatures, which causes the PEG-liposomes to naturally accumulate in the tumor. This also allows for patients to receive lower and fewer doses of the drug and experience fewer side effects. This is also being attempted with nanoparticles but has not been tested on FDCS. In 2008 COP plus (PEG)-liposomal doxorubicin went into a clinical trial for an FDCS patient to replace the CHOP regimen, and after 5 years the patient remains in CR.

Newer cases are also starting to be treated by taxotere and gemcitabine. Taxotere is similar to Oncovin used in CHOP; it irreversibly binds beta tubulin halting formation of microtubules. Taxotere has an added benefit though; it also phosphorylates bcl-2 to halt the anti-apoptotic pathway. The dual effect of taxotere on integral cancer pathways makes it a more potent drug than Oncovin. Gemcitabene is a nucleoside analog and when incorporated into DNA during replication leads to apoptosis; the fluorine on the 2’ carbon atom stops other nucleosides from attaching. The most important part of this combination therapy, however, is the synergism between the drugs. While researchers are not entirely sure of the mechanism, there is evidence of synergistic effects of taxotere and gemcitabine when used in combination. This allows for decreased dosages of each single agent with an increased apoptotic response.

The Stehlin Foundation currently offers DSRCT patients the opportunity to send samples of their tumors free of charge for testing. Research scientists are growing the samples on nude mice and testing various chemical agents to find which are most effective against the individual's tumor.

Patients with advanced DSRCT may qualify to participate in clinical trials that are researching new drugs to treat the disease.

Removal of the mast cell tumor through surgery is the treatment of choice. Antihistamines, such as diphenhydramine, are given prior to surgery to protect against the effects of histamine released from the tumor. Wide margins (two to three centimeters) are required because of the tendency for the tumor cells to be spread out around the tumor. If complete removal is not possible due to the size or location, additional treatment, such as radiation therapy or chemotherapy, may be necessary. Prednisone is often used to shrink the remaining tumor portion. H2 blockers, such as cimetidine, protect against stomach damage from histamine. Vinblastine and CCNU are common chemotherapy agents used to treat mast cell tumors.

Toceranib and masitinib, examples of receptor tyrosine kinase inhibitors, are used in the treatment of canine mast cell tumors. Both were recently approved by the U.S. Food and Drug Administration (FDA) as dog-specific anticancer drugs.

Grade I or II mast cell tumors that can be completely removed have a good prognosis. One study showed about 23 percent of incompletely removed grade II tumors recurred locally. Any mast cell tumor found in the gastrointestinal tract, paw, or on the muzzle has a guarded prognosis. Previous beliefs that tumors in the groin or perineum carried a worse prognosis have been discounted. Tumors that have spread to the lymph nodes or other parts of the body have a poor prognosis. Any dog showing symptoms of mastocytosis or with a grade III tumor has a poor prognosis. Dogs of the Boxer breed have a better than average prognosis because of the relatively benign behavior of their mast cell tumors. Multiple tumors that are treated similarly to solitary tumors do not seem to have a worse prognosis.

Mast cell tumors do not necessarily follow the histological prognosis. Further prognostic information can be provided by AgNOR stain of histological or cytological specimen. Even then, there is a risk of unpredictable behavior.

Induction chemotherapy is the treatment adapted for shrinking the tonsil tumor. It is given prior to other treatments, hence, the term induction. After the therapy is completed, the patient is asked to rest and is evaluated over a period of time. Then the patient is given chemo-radiation therapy (a combination of chemotherapy and radiation) to completely destroy the tumor cells.

Early radio-sensitive tumors are treated by radiotherapy along with irradiation of cervical nodes. The radiation uses high-energy X-rays, electron beams, or radioactive isotopes to destroy cancer cells.

Aggressive surgical removal of the tumor and any enlarged sublumbar lymph nodes is essential for treatment of the tumor and associated hypercalcaemia. There is a high recurrence rate, although removal of lymph nodes with metastasis may improve survival time. Radiation therapy and chemotherapy may be helpful in treatment. Severe hypercalcaemia is treated with aggressive IV fluid therapy using sodium chloride and medications such as loop diuretics (increased kidney excretion of calcium) and aminobisphosphonates (decreased calcium release from bones). A poorer prognosis is associated with large tumor size (greater than 10 cm), hypercalcaemia, and distante metastasis. Early, incidental diagnosis of small anal sac masses may lead to a better prognosis with surgery alone (ongoing study).

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.

Chemotherapy is the mainstay of treatment for lymphoma in cats. Most of the drugs used in dogs are used in cats, but the most common protocol uses cyclophosphamide, vincristine, and prednisone. Gastrointestinal lymphoma has also commonly been treated with a combination of prednisolone and high dose pulse chlorambucil with success. The white blood cell count must be monitored. Remission and survival times are comparable to dogs. Lower stage lymphoma has a better prognosis. Multicentric lymphoma has a better response to treatment than the gastrointestinal form, but infection with FeLV worsens the prognosis.

About 75% of cats treated with chemotherapy for lymphoma go into remission. Unfortunately, after an initial remission, most cats experience a relapse, after which they have a median survival of 6 months. However, about one-third of cats treated with chemotherapy will survive more than 2 years after diagnosis; a small number of these cats may be cured of their disease. Untreated, most cats with lymphoma die within 4–6 weeks. Most cats tolerate their chemotherapy well, and fewer than 5% have severe side effects. Cats do not lose their fur from chemotherapy, though loss of whiskers is possible. Other side effects include low white blood cell count, vomiting, loss of appetite, diarrhea, or fatigue. These can typically be controlled well, and most cats have a good quality of life during treatment. If a cat relapses after attaining remission, the cat can be treated with different chemotherapy drugs to try for a second remission. The chances of a second remission are much lower than the chances of obtaining a first, and the second remission is often shorter than the first.

In localized, resectable adult GISTs, if anatomically and physiologically feasible, surgery is the primary treatment of choice. Surgery can be potentially curative, but watchful waiting may be considered in small tumors in carefully selected situations. Post-surgical adjuvant treatment may be recommended. Lymph node metastases are rare, and routine removal of lymph nodes is typically not necessary. Laparoscopic surgery, a minimally invasive abdominal surgery using telescopes and specialized instruments, has been shown to be effective for removal of these tumors without needing large incisions. The clinical issues of exact surgical indications for tumor size are controversial. The decision of appropriate laparoscopic surgery is affected by tumor size, location, and growth pattern.

Radiotherapy has not historically been effective for GISTs and GISTs do not respond to most chemotherapy medications, with responses in less than 5%. However, three medications have been identified for clinical benefit in GIST: imatinib, sunitinib, and regorafenib.

Imatinib (Glivec/Gleevec), an orally administered drug initially marketed for chronic myelogenous leukemia based on bcr-abl inhibition, also inhibits both "c-kit" tyrosine kinase mutations and PDGFRA mutations other than D842V, is useful in treating GISTs in several situations. Imatinib has been used in selected neoadjuvant settings. In the adjuvant treatment setting, the majority of GIST tumors are cured by surgery, and do not need adjuvant therapy. However, a substantial proportion of GIST tumors have a high risk of recurrence as estimated by a number of validated risk stratification schemes, and can be considered for adjuvant therapy. The selection criteria underpinning the decision for possible use of imatinib in these settings include a risk assessment based on pathological factors such as tumor size, mitotic rate, and location can be used to predict the risk of recurrence in GIST patients. Tumors <2 cm with a mitotic rate of <5/50 HPF have been shown to have lower risk of recurrence than larger or more aggressive tumors. Following surgical resection of GISTs, adjuvant treatment with imatinib reduces the risk of disease recurrence in higher risk groups. In selected higher risk adjuvant situations, imatinib is recommended for 3 years.

Imatinib was approved for metastatic and unresectable GIST by the US FDA, February 1, 2002. The two-year survival of patients with advanced disease has risen to 75–80% following imatinib treatment.

If resistance to imatinib is encountered, the multiple tyrosine kinase inhibitor sunitinib (marketed as Sutent) can be considered.

The effectiveness of imatinib and sunitinib depend on the genotype. cKIT- and PDGFRA-mutation negative GIST tumors are usually resistant to treatment with imatinib as is neurofibromatosis-1-associated wild-type GIST. A specific subtype of PDGFRA-mutation, D842V, is also insensitive to imatinib.

Regorafenib (Stivarga) was FDA approved in 2013 for advanced GISTs that cannot be surgically removed and that no longer respond to imatinib (Gleevec) and sunitinib (Sutent).

The prognosis varies according with the type of ALCL. During treatment, relapses may occur but these typically remain sensitive to chemotherapy.

Those with ALK positivity have better prognosis than ALK negative ALCL. It has been suggested that ALK-negative anaplastic large-cell lymphomas derive from other T-cell lymphomas that are morphologic mimics of ALCL in a final common pathway of disease progression. Whereas ALK-positive ALCLs are molecularly characterized and can be readily diagnosed, specific immunophenotypic or genetic features to define ALK-negative ALCL are missing and their distinction from other T-cell non-Hodgkin lymphomas (T-NHLs) remains controversial, although promising diagnostic tools for their recognition have been developed and might be helpful to drive appropriate therapeutic protocols.

Systemic ALK+ ALCL 5-year survival: 70–80%.

Systemic ALK- ALCL 5-year survival: 15–45%.

Primary Cutaneous ALCL: Prognosis is good if there is not extensive involvement regardless of whether or not ALK is positive with an approximately 90% 5-year survival rate.

Breast implant-associated ALCL has an excellent prognosis when the lymphoma is confined to the fluid or to the capsule surrounding the breast implant. This tumor can be recurrent and grow as a mass around the implant capsule or can extend to regional lymph nodes if not properly treated.

The prognosis for DSRCT remains poor. Prognosis depends upon the stage of the cancer. Because the disease can be misdiagnosed or remain undetected, tumors frequently grow large within the abdomen and metastasize or seed to other parts of the body.

There is no known organ or area of origin. DSRCT can metastasize through lymph nodes or the blood stream. Sites of metastasis include the spleen, diaphragm, liver, large and small intestine, lungs, central nervous system, bones, uterus, bladder, genitals, abdominal cavity, and the brain.

A multi-modality approach of high-dose chemotherapy, aggressive surgical resection, radiation, and stem cell rescue improves survival for some patients. Reports have indicated that patients will initially respond to first line chemotherapy and treatment but that relapse is common.

Some patients in remission or with inoperable tumor seem to benefit from long term low dose chemotherapy, turning DSRCT into a chronic disease.