Surgical resection is usually ineffective because of the depth of the tumour. Treatment with irradiation and corticosteroids often only produces a partial response and tumour recurs in more than 90% of patients. Median survival is 10 to 18 months in immunocompetent patients, and less in those with AIDS. The addition of IV methotrexate and folinic acid (leucovorin) may extend survival to a median of 3.5 years. If radiation is added to methotrexate, median survival time may increase beyond 4 years. However, radiation is not recommended in conjunction with methotrexate because of an increased risk of leukoencephalopathy and dementia in patients older than 60. In AIDS patients, perhaps the most important factor with respect to treatment is the use of highly active anti-retroviral therapy (HAART), which affects the CD4+ lymphocyte population and the level of immunosuppression. The optimal treatment plan for patients with PCNSL has not been determined. Combination chemotherapy and radiotherapy at least doubles survival time, but causes dementia and leukoencephalopathy in at least 50% of patients who undergo it. The most studied chemotheraputic agent in PCNSL is methotrexate (a folate analogue that interferes with DNA repair). Methotrexate therapy in patients with PCNSL typically requires hospitalization for close monitoring and intravenous fluids. Leucovorin is often given for the duration of the therapy. Standard chemotherapeutic regimens for lymphoma such as CHOP are ineffective in PCNSL, probably due to poor penetration of the agents through the blood brain barrier.

Newer treatments, such as high dose chemotherapy combined with stem cell transplant are proving to increase survival by years.

A phase 1 clinical trial of ibrutinib - an inhibitor of Bruton's tyrosine kinase - in 13 patients reported responses in 10 (77%). Five of the responses were complete.

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.

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.

The initial response to radiotherapy is often excellent, and may result in a complete remission. However, the duration of response with radiotherapy alone remains short, with median survival after treatment with radiotherapy just 18 months. Methotrexate based chemotherapy markedly improves survival, with some studies showing median survival after methotrexate chemotherapy reaching 48 months.

In general, the first line of treatment for Burkitt’s lymphoma is intensive chemotherapy. A few of these regimens are: the GMALL-B-ALL/NHL2002 protocol, the modified Magrath regimen (R-CODOX-M/IVAC). COPADM, hyper-CVAD, and the Cancer and Leukemia Group B (CALGB) 8811 regimen; these can be associated with rituximab. In older patients treatment may be dose-adjusted EPOCH with rituximab.

The effects of the chemotherapy, as with all cancers, depend on the time of diagnosis. With faster-growing cancers, such as Burkitt's, the cancer actually responds faster than with slower-growing cancers. This rapid response to chemotherapy can be hazardous to the patient, as a phenomenon called "tumor lysis syndrome" could occur. Close monitoring of the patient and adequate hydration is essential during the process. Since Burkitts lymphoma has high propensity to spread to the central nervous system (lymphomatous meningitis), intrathecal chemotherapy with methotrexate and/or ARA-C and/or prednisolone is given alongside with systemic chemotherapy.

Chemotherapy

- cyclophosphamide

- doxorubicin

- vincristine

- methotrexate

- cytarabine

- ifosfamide

- etoposide

- rituximab

Other treatments for Burkitt's lymphoma include immunotherapy, bone marrow transplants, stem cell transplant, surgery to remove the tumor, and radiotherapy.

It is generally resistant to cancer chemotherapy drugs that are active against other lymphomas, and carries a poor prognosis.

Sirolimus has been proposed as a treatment option.

Radiation therapy is often part of the treatment for DLBCL. It is commonly used after the completion of chemotherapy. Radiation therapy alone is not an effective treatment for this disease.

Current treatment typically includes R-CHOP, which consists of the traditional CHOP, to which rituximab has been added. This regimen has increased the rate of complete response for DLBCL patients, particularly in elderly patients.R-CHOP is a combination of one monoclonal antibody (rituximab), three chemotherapy agents (cyclophosphamide, doxorubicin, vincristine), and one steroid (prednisone). These drugs are administered intravenously, and the regimen is most effective when it is administered multiple times over a period of months. People often receive this type of chemotherapy through a PICC line (peripherally inserted central catheter) in their arm near the elbow or a surgically implanted venous access port. The number of cycles of chemotherapy given depends on the stage of the disease — patients with limited disease typically receive three cycles of chemotherapy, while patients with extensive disease may need to undergo six to eight cycles. A recent approach involves obtaining a PET scan after the completion of two cycles of chemotherapy, to assist the treatment team in making further decisions about the future course of treatment.Older people often have more difficulty tolerating therapy than younger people. Lower intensity regimens have been attempted in this age group.

Radiotherapy is the most effective treatment for local disease either as the sole treatment for low-grade lymphoma or in combination with chemotherapy for intermediate- and high-grade lymphoma. Radiotherapy dose in range of 30-45 Gy administered in fractions are advised in treating the local orbital lymphomas.

Current HAART options are combinations (or "cocktails") consisting of at least three medications belonging to at least two types, or "classes," of antiretroviral agents. Initially treatment is typically a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside analog reverse transcriptase inhibitors (NRTIs). Typical NRTIs include: zidovudine (AZT) or tenofovir (TDF) and lamivudine (3TC) or emtricitabine (FTC). Combinations of agents which include protease inhibitors (PI) are used if the above regimen loses effectiveness.

The World Health Organization and United States recommends antiretrovirals in people of all ages including pregnant women as soon as the diagnosis is made regardless of CD4 count. Once treatment is begun it is recommended that it is continued without breaks or "holidays". Many people are diagnosed only after treatment ideally should have begun. The desired outcome of treatment is a long term plasma HIV-RNA count below 50 copies/mL. Levels to determine if treatment is effective are initially recommended after four weeks and once levels fall below 50 copies/mL checks every three to six months are typically adequate. Inadequate control is deemed to be greater than 400 copies/mL. Based on these criteria treatment is effective in more than 95% of people during the first year.

Benefits of treatment include a decreased risk of progression to AIDS and a decreased risk of death. In the developing world treatment also improves physical and mental health. With treatment there is a 70% reduced risk of acquiring tuberculosis. Additional benefits include a decreased risk of transmission of the disease to sexual partners and a decrease in mother-to-child transmission. The effectiveness of treatment depends to a large part on compliance. Reasons for non-adherence include poor access to medical care, inadequate social supports, mental illness and drug abuse. The complexity of treatment regimens (due to pill numbers and dosing frequency) and adverse effects may reduce adherence. Even though cost is an important issue with some medications, 47% of those who needed them were taking them in low and middle income countries as of 2010 and the rate of adherence is similar in low-income and high-income countries.

Specific adverse events are related to the antiretroviral agent taken. Some relatively common adverse events include: lipodystrophy syndrome, dyslipidemia, and diabetes mellitus, especially with protease inhibitors. Other common symptoms include diarrhea, and an increased risk of cardiovascular disease. Newer recommended treatments are associated with fewer adverse effects. Certain medications may be associated with birth defects and therefore may be unsuitable for women hoping to have children.

Treatment recommendations for children are somewhat different from those for adults. The World Health Organization recommends treating all children less than 5 years of age; children above 5 are treated like adults. The United States guidelines recommend treating all children less than 12 months of age and all those with HIV RNA counts greater than 100,000 copies/mL between one year and five years of age.

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.

There is currently no cure or effective HIV vaccine. Treatment consists of highly active antiretroviral therapy (HAART) which slows progression of the disease. As of 2010 more than 6.6 million people were taking them in low and middle income countries. Treatment also includes preventive and active treatment of opportunistic infections.

Treatment with dose-adjusted EPOCH with rituximab has shown promising initial results in a small series of patients (n=17), with a 100% response rate, and 100% overall survival and progression-free survival at 28 months (median follow-up).

Treatment depends on the grade (I-III) but typically consist of cortisone, rituximab and chemotherapy (etoposide, vincristine, cyclophosphamide, doxorubicin). Methotrexate has been seen to induce LYG. Interferon alpha has been used by the US National Cancer Institute with varying results. In recent years hematopoietic stem cell transplantation has been performed on LYG-patients with relative good success; a 2013 study identifying 10 cases found that 8 patients survived the treatment and were disease free several years later. Two of the disease free patients later died, one from suicide and one from graft versus host disease after a second transplantation 4 years later. The remaining two patients died from sepsis after the transplantation.

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.

The most common chemotherapy used for non-Hodgkin lymphoma is R-CHOP.

Treatment with chemotherapy has been used with some success, particularly using lomustine, prednisone, doxorubicin, and cyclophosphamide. Because of the rapid progression of this aggressive disease, the prognosis is very poor.

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.

As described above, chloromas should always be considered manifestations of systemic disease, rather than isolated local phenomena, and treated as such. In the patient with newly diagnosed leukemia and an associated chloroma, systemic chemotherapy against the leukemia is typically used as the first-line treatment, unless an indication for local treatment of the chloroma (e.g. compromise of the spinal cord) emerges. Chloromas are typically quite sensitive to standard antileukemic chemotherapy. Allogeneic hematopoietic stem cell transplantation should be considered in fit patients with suitable available donor, as long term remissions have been reported.

If the chloroma is persistent after completion of induction chemotherapy, local treatment, such as surgery or radiation therapy, may be considered, although neither has an effect on survival.

Patients presenting with a primary chloroma typically receive systemic chemotherapy, as development of acute leukemia is nearly universal in the short term after detection of the chloroma.

Patients treated for acute leukemia who relapse with an isolated chloroma are typically treated with systemic therapy for relapsed leukemia. However, as with any relapsed leukemia, outcomes are unfortunately poor.

Patients with "preleukemic" conditions, such as myelodysplastic syndromes or myeloproliferative syndromes, who develop a chloroma are often treated as if they have transformed to acute leukemia.

AIDS-related lymphoma describes lymphomas occurring in patients with acquired immunodeficiency syndrome (AIDS).

A lymphoma is a type of cancer arising from lymphoid cells. In AIDS, the incidences of non-Hodgkin's lymphoma, primary cerebral lymphoma and Hodgkin's disease are all increased. There are three different varieties of AIDS-related lymphoma: Diffuse large B-cell lymphoma, B-cell immunoblastic lymphoma, and Burkitt's lymphoma (small non-cleaved cell lymphoma).

Non-Hodgkin's lymphoma (NHL) is present in about 1%–3% of HIV seropositive people at the time of the initial diagnosis of HIV. However, it is believed that such patients have been seropositive for a prolonged period, but have simply not had their infections recognized previously. This is so because immunodysregulation must exist for an extended interval of time, in order for a lymphoproliferative process to evolve in that context.

The Center for Disease Control and Prevention (CDC) included certain types of non-Hodgkin's lymphoma as AIDS-defining cancers in 1987. Immune suppression rather than HIV itself is implicated in the pathogenesis of this malignancy, with a clear correlation between the degree of immune suppression and the risk of developing NHL. Additionally, other retroviruses such as HTLV may be spread by the same mechanisms that spread HIV, leading to an increased rate of co-infection. The natural history of HIV infection has been greatly changed over time. As a consequence, rates of non-Hodgkin's lymphoma (NHL) in people infected with HIV has significantly declined in recent years.

Autologous stem-cell transplants are shown to be an effective treatment. However, this should be only considered for certain people due to toxicity concerns. It is possible that the transplant may cause problems like septic shock.

Treatment also involves central nervous system penetrating chemotherapy. Options include intrathecal, intraventricular, and systemic chemotherapy. These must penetrate the blood-brain barrier in order to be effective. Sometimes mixing multiple forms of treatment with chemotherapy seems to be the best route. For example, some significant improvement has been shown as a result of cranial radiation treatment preceding a brief course of intrathecal chemotherapy. Although this is an effective treatment to do, penetrating the blood-brain barrier can cause side effects due to the toxicity in the nervous system. These would include dizziness, confusion, and changes in mental status. Another form could be the use of pharmaceuticals, which have all shown positive results for treatment but should always be consulted with a physician to asses risks.

Available treatment falls into two modalities: treating infections and boosting the immune system.

Prevention of Pneumocystis pneumonia using trimethoprim/sulfamethoxazole is useful in those who are immunocompromised. In the early 1950s Immunoglobulin(Ig) was used by doctors to treat patients with primary immunodeficiency through intramuscular injection. Ig replacement therapy are infusions that can be either subcutaneous or intravenously administrated, resulting in higher Ig levels for about three to four weeks, although this varies with each patient.