Of all cancers involving the same class of blood cell, 2.3% of cases are Burkitt lymphoma. Epstein-Barr virus infection is strongly correlated with this cancer.

Of all cancers involving the same class of blood cell (lymphoproliferative disorders), 22% of cases are follicular lymphomas.

Of all cancers involving the same class of blood cell, 8% of cases are MALT lymphomas.

Histologic transformation to diffuse large B-cell lymphoma (DLBCL) can occur in up to 12% of cases. After transformation, neoplastic cells carry monoclonal immunoglobulin gene rearrangements. Histological transformation may lead to poor prognosis and therefore repeat biopsy is required at relapse.

One study found a transformation rate of 7.6%, and suggested that prior exposure to chemotherapy and a presentation with splenic involvement were associated with increased risks of transformation.

One study has suggested improved overall survival in response to chemotherapy for African Americans.

6% of non-Hodgkin lymphoma cases are mantle cell lymphoma. As of 2015, the ratio of males to females affected is about 4:1.

The lymphoma is more common in the young and in males.

A 2008 study found an increased risk of ALCL of the breast in women with silicone breast implants (protheses), although the overall risk remained exceedingly low due to the rare occurrence of the tumor.

There is no known cause for any type of Marginal Zone non-Hodgkins lymphoma, but it occurs when the body produces large amounts of abnormal lymphocytes.

Factors that may increase an individuals chance of developing nodal MZL are being over the age of 60 and having been infected with hepatitis C virus. Factors that may increase an individuals chance of developing MALT lymphoma include being over the age of 50, having an autoimmune condition (rheumatoid arthritis, Hashimoto's thyroiditis), and long lasting chronic inflammation due to infection (H.pylori, Sjogren syndrome, chlamidia infection, Borrelia infection, Campylobacter jejuni infection). Factors that increase an individuals risk of developing splenic MZL include the hepatitis C virus, Epstein-Barr virus, malaria, Sjogren syndrome, and lupus.

In order to reduce the chances of developing MZL, an individual can decrease their exposure to the possible risk factors.

Primary cerebral lymphoma (or "primary central nervous system lymphoma") is a form of NHL. It is very rare in immunocompetent people, with an incidence of 5–30 cases per million person-years. However the incidence in immunocompromised individuals is greatly increased, up to 100 per million person-years.

Primary cerebral lymphoma is strongly associated with Epstein–Barr virus (EBV). The presence of EBV DNA in cerebrospinal fluid is highly suggestive of primary cerebral lymphoma.

Treatment of AIDS patients with antiretroviral drugs reduces the incidence of primary cerebral lymphoma.

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.

This rare form of leukemia is more common among Asians in comparison to other ethnic groups. It is typically diagnosed in adolescents and young adults, with a slight predominance in males.

The incidence of Hodgkin's disease in the general population is about 10–30 per million person-years. This increases to 170 per million person-years in HIV positive patients.

Median survival is around 10 years, but the range is wide, from less than one year, to more than 20 years. Some patients may never need treatment. The overall survival rate at five years is 72–77%. Recent advances and addition of Rituximab, improved median survival. Recent reports for the period 1986 and 2012 estimates median survival of over 20 years.

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

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).

Lymphoma is the most common form of hematological malignancy, or "blood cancer", in the developed world.

Taken together, lymphomas represent 5.3% of all cancers (excluding simple basal cell and squamous cell skin cancers) in the United States and 55.6% of all blood cancers.

According to the U.S. National Institutes of Health, lymphomas account for about 5%, and Hodgkin lymphoma in particular accounts for less than 1% of all cases of cancer in the United States.

Because the whole system is part of the body's immune system, patients with a weakened immune system such as from HIV infection or from certain drugs or medication also have a higher incidence of lymphoma.

Treatment of Hodgkin's disease has been improving over the past few decades. Recent trials that have made use of new types of chemotherapy have indicated higher survival rates than have previously been seen. In one recent European trial, the 5-year survival rate for those patients with a favorable prognosis (FFP) was 98%, while that for patients with worse outlooks was at least 85%.

In 1998, an international effort identified seven prognostic factors that accurately predict the success rate of conventional treatment in patients with locally extensive or advanced stage Hodgkin's lymphoma. Freedom from progression (FFP) at 5 years was directly related to the number of factors present in a patient. The 5-year FFP for patients with zero factors is 84%. Each additional factor lowers the 5-year FFP rate by 7%, such that the 5-year FFP for a patient with 5 or more factors is 42%.

The adverse prognostic factors identified in the international study are:

- Age ≥ 45 years

- Stage IV disease

- Hemoglobin < 10.5 g/dl

- Lymphocyte count < 600/µl or < 8%

- Male

- Albumin < 4.0 g/dl

- White blood count ≥ 15,000/µl

Other studies have reported the following to be the most important adverse prognostic factors: mixed-cellularity or lymphocyte-depleted histologies, male sex, large number of involved nodal sites, advanced stage, age of 40 years or more, the presence of B symptoms, high erythrocyte sedimentation rate, and bulky disease (widening of the mediastinum by more than one third, or the presence of a nodal mass measuring more than 10 cm in any dimension.)

More recently, use of positron emission tomography (PET) early after commencing chemotherapy has demonstrated to have powerful prognostic ability. This enables assessment of an individual's response to chemotherapy as the PET activity switches off rapidly in patients who are responding. In this study, after two cycles of ABVD chemotherapy, 83% of patients were free of disease at 3 years if they had a negative PET versus only 28% in those with positive PET scans. This prognostic power exceeds conventional factors discussed above. Several trials are underway to see if PET-based risk adapted response can be used to improve patient outcomes by changing chemotherapy early in patients who are not responding.

In the United States, about 500 patients are diagnosed with Richter's transformation each year.

The prognosis is generally poor. The "RS score" (Richter syndrome score), which is an estimate of the patient's prognosis, is based on the patient's performance status, LDH, platelet count, the size of the lymphoma tumors, and the number of prior therapies already received. Overall, the median survival is between five and eight months. Untreated, RS is invariably fatal.

The Hodgkin's lymphoma variant of Richter's carries a better prognosis than the predominant diffuse large B-cell lymphoma type, but a worse prognosis than a "de novo" case of Hodgkin's.

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.

This lymphoma is rare, comprising less than 5% of all cases, and is most common in young adults and adolescents. A distinct male gender preference has been described.

Unlike some other lymphomas, whose incidence increases with age, Hodgkin's lymphoma has a bimodal incidence curve; that is, it occurs most frequently in two separate age groups, the first being young adulthood (age 15–35) and the second being in those over 55 years old although these peaks may vary slightly with nationality. Overall, it is more common in males, except for the nodular sclerosis variant, which is slightly more common in females. The annual incidence of Hodgkin's lymphoma is 2.7 per 100,000 per persons per year, and the disease accounts for slightly less than 1% of all cancers worldwide.

In 2010, globally it resulted in about 18,000 deaths down from 19,000 in 1990.

The incidence of Hodgkin's lymphoma is increased in patients with HIV infection. In contrast to many other lymphomas associated with HIV infection it occurs most commonly in patients with higher CD4 T cell counts.

The factors of poor prognosis for patients with thyroid lymphoma are advanced stage of the tumor, large size (>10 cm) as well as spreading to mediastinum. The overall survival for primary thyroid lymphoma is 50% to 70%, ranging from 80% in stage IE to less than 36% in stage IIE and IVE in 5 years.

The cell of origin for this disease is an immature cytotoxic T-cell clonally expressing the γδ T-cell receptor. This disease is seen more often in immunosuppressed solid organ transplant recipients, an association that has led to the hypothesis that long-term immune stimulation in the setting of immunosuppression is the causative agent.

Cases of hepatosplenic T-cell lymphoma (HSTCL) have been reported in patients treated with the immunosuppressants azathioprine, infliximab and adalimumab. The majority occurred in patients with inflammatory bowel disease. Adolescents and young adult males were the major cohort of cases. They presented with a very aggressive disease course and, with one exception, died of the lymphoma. The FDA has required changes to the labeling to inform users and clinicians of the issue.

A second regimen under evaluation is R-EPOCH (rituximab with etoposide-prednisone-vincristine-doxorubicin-cyclophosphamide), which demonstrated a 5-year progression-free survival (PFS) of 79% in a phase II trial. A phase III trial, CALGB 50303, is now comparing R-EPOCH with R-CHOP in patients with newly diagnosed DLBCL.

One area of active research is on separating patients into groups based on their prognosis and how likely they are to benefit from different drugs. Methods like gene expression profiling and next-generation sequencing may result in more effective and more personalized treatment.