Non-Hodgkin lymphoma


Non-Hodgkin lymphoma is a group of blood cancers that includes all types of lymphomas except Hodgkin lymphomas. Symptoms include enlarged lymph nodes, fever, night sweats, weight loss and tiredness. Other symptoms may include bone pain, chest pain or itchiness. Some forms are slow-growing, while others are fast-growing.
Lymphomas are types of cancer that develop from lymphocytes, a type of white blood cell. Risk factors include poor immune function, autoimmune diseases, Helicobacter pylori infection, hepatitis C, obesity, and Epstein–Barr virus infection. The World Health Organization classifies lymphomas into five major groups, including one for Hodgkin lymphoma. Within the four groups for NHL are over 60 specific types of lymphoma. Diagnosis is by examination of a bone marrow or lymph node biopsy. Medical imaging is done to help with cancer staging.
Treatment depends on whether the lymphoma is slow- or fast-growing and if it is in one area or many areas. Treatments may include chemotherapy, radiation, immunotherapy, targeted therapy, stem-cell transplantation, surgery, or watchful waiting. If the blood becomes overly thick due to high numbers of antibodies, plasmapheresis may be used. Radiation and some chemotherapy, however, increase the risk of other cancers, heart disease, or nerve problems over the subsequent decades.
In 2015, about 4.3 million people had non-Hodgkin lymphoma, and 231,400 died. In the United States, 2.1% of people are affected at some point in their life. The most common age of diagnosis is between 65 and 75 years old. The five-year survival rate in the United States is 71%.

Signs and symptoms

The signs and symptoms of non-Hodgkin lymphoma vary depending upon its location within the body. Symptoms include enlarged lymph nodes, fever, night sweats, weight loss, and tiredness. Other symptoms may include bone pain, chest pain, or itchiness. Some forms are slow growing, while others are fast growing. Enlarged lymph nodes may cause lumps to be felt under the skin when they are close to the surface of the body. Lymphomas in the skin may also result in lumps, which are commonly itchy, red, or purple. Lymphomas in the brain can cause weakness, seizures, problems with thinking, and personality changes.
While an association between non-Hodgkin lymphoma and endometriosis has been described, these associations are tentative.

Causes

The many different forms of lymphoma probably have different causes. These possible causes and associations with at least some forms of NHL include:
Familial lymphoid cancer is rare. The familial risk of lymphoma is elevated for multiple lymphoma subtypes, suggesting a shared genetic cause. However, a family history of a specific subtype is most strongly associated with risk for that subtype, indicating that these genetic factors are subtype-specific. Genome-wide association studies have successfully identified 67 single-nucleotide polymorphisms from 41 loci, most of which are subtype specific.

HIV/AIDS

The Centers for Disease Control and Prevention included certain types of non-Hodgkin 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 lymphoma in people infected with HIV has significantly declined in recent years.

Treatment

The traditional treatment of NHL includes chemotherapy, radiotherapy, and stem-cell transplants. There have also been developments in immunotherapy used in the treatment of NHL. The most common chemotherapy used for B-cell non-Hodgkin lymphoma is R-CHOP, which is a regimen of four drugs plus rituximab.
If participants receive stem-cell transplants, they can develop a graft-versus-host disease. Therefore, Fisher et al. conducted a Cochrane review with randomised controlled trials in 2019 to measure the safety and efficacy of mesenchymal stromal cells for people suffering from a graft-versus-host disease after receiving a haematopoietic stem-cell transplantation as treatment for their haematological disease. Fisher et al. included trials that used MSCs either for therapeutic or prophylactic reasons. The exact inclusion and exclusion criteria and information regarding the dose can be found in the original Cochrane review. In the therapeutic trials, it was necessary that the study participants already suffered from a GvHD. Fisher et al. conducted one analysis: MSCs compared to control/ placebo for treating immune mediated inflammation post-transplantation and in autoimmunity: Mesenchymal stromal cells may reduce the all-cause mortality if they are used for a therapeutic reason. Moreover, the therapeutic use of MSCs may increase the complete response of acute and chronic GvHD, but the evidence is very uncertain. The evidence suggests that MSCs for prophylactic reason result in little to no difference in the all-cause mortality, in the relapse of malignant diseases, and in the incidence of acute GvHD. The evidence suggests that MSCs for prophylactic reason reduce the incidence of chronic GvHD.
If participants receive a chemotherapy or a stem cell transplant, they might have a higher risk for bleeding. Therefore, Estcourt et al. conducted a Cochrane review with randomised controlled trials in 2012 to assess which use of platelet transfusions is the most effective one to prevent bleeding if people suffer from a haematological disorder and undergo a stem-cell transplantation or a chemotherapy. Study participation was only possible if the patients did not have an active bleed within the last 5 days and did not receive a previous platelet transfusion because of the chemotherapy or stem-cell transplantation. The exact inclusion and exclusion criteria and details regarding the dose can be found in the original Cochrane review. Estcourt et al. conducted four analyses to answer their research question. In the first analysis, they compared therapeutic/ non-prophylactic platelet transfusions to prophylactic platelet transfusions: The evidence suggests that therapeutic platelet transfusions result in little to no difference in the mortality secondary to bleeding. Furthermore, they may result in a slight reduction in the number of days on which a significant bleeding event occurred. The evidence suggests that therapeutic platelet transfusions result in a large increase in the number of patients with at least one significant bleeding event and they likely result in a large reduction in the number of platelet transfusions. In the second analysis, the review authors conducted a comparison of prophylactic platelet transfusions at threshold of 10.000 to a higher transfusion threshold : Prophylactic platelet transfusions at threshold of 10.000 may result in little to no difference in the mortality due to bleeding. These transfusions probably reduce the number of platelet transfusions per patient slightly. Prophylactic platelet transfusions at threshold of 10.000 probably increase the number of patients with at least one significant bleeding event and they likely result in a large increase in the number of days on which a significant bleeding event occurred. Prophylactic platelet transfusion with one dose schedules were compared to prophylactic platelet transfusions with another dose schedule in the third analysis: Prophylactic platelet transfusions at one dose schedule may result in little to no difference in the mortality secondary to bleeding if low dosage platelet transfusions are compared to standard dose platelet transfusions. Furthermore, the transfusions at one dose schedule probably result in little to no difference in the mortality secondary to bleeding if high dose platelet transfusions and standard dosage platelet transfusions are compared to each other. Prophylactic platelet transfusions with one dose schedule result in little to no difference in the number of participants with a significant bleeding event if low dosage platelet transfusions or high dosage platelet transfusions are compared to standard dose platelet transfusions. The last analysis was conducted to compare prophylactic platelet transfusions to platelet-poor plasma: The evidence is very uncertain about the effect of prophylactic platelet transfusion on mortality secondary to bleeding, the number of participants with a significant bleeding event and the number of platelet transfusions. Moreover, Estcourt et al. renewed the second analysis from their Cochrane review from 2012 in 2015 with randomised controlled trials and aimed to evaluate whether different platelet transfusion thresholds for the management of prophylactic platelet transfusions have an influence on the safety and efficacy for patients that suffer from a haematological disorder and receive a stem cell transplantation or myelosuppressive chemotherapy. Estcourt et al. conducted the following analysis: Prophylactic platelet transfusion at threshold of 10.000 compared to higher transfusion threshold : The evidence suggests that prophylactic platelet transfusions at threshold of 10.000 result in little to no different in the time to the first bleeding episode, the number of participants with WHO Grade 3 or 4 bleeding and clinically significant bleedings per participant. The evidence suggests that prophylactic platelet transfusions at threshold of 10.000 reduce the number of platelet transfusions per participants slightly. Moreover, the evidence suggests that these transfusions increase the number of participants with at least one significant bleeding event. Prophylactic platelet transfusions at threshold of 10.000 may result in a large increase in the mortality due to all causes. Apart from the time to the first bleeding, all endpoints are related to the first 30 days after the study entry.
An additional treatment might support the standard treatment. Therefore, Knips et al. conducted a Cochrane review with randomised controlled trials in 2019 to re-evaluate the safety, efficacy and feasibility of physical exercises in addition to the standard treatment for  adult patients with haematological malignancies. The exact inclusion and exclusion criteria and further details can be found in the original Cochrane review. The study participants were in disease stage I to IV. As aerobic physical exercises were only an additional treatment, participants also received chemotherapies or stem cell transplantations/ bone marrow transplantations. Knips et al. compared aerobic physical exercises additional to the standard treatment to standard treatment alone: The evidence is very uncertain about the effect of aerobic physical exercises on anxiety and serious adverse events. Aerobic physical exercises may result in little to no difference in the mortality, in the quality of life and in the physical functioning. These exercises may result in a slight reduction in depression. Furthermore, aerobic physical exercises probably reduce fatigue.

Prognosis

Prognosis depends on the subtype, the staging, a person's age, and other factors. Across all subtypes, 5-year survival for NHL is 71%, ranging from 81% for Stage 1 disease to 61% for Stage 4 disease.

Epidemiology

Globally, as of 2010, there were 210,000 deaths, up from 143,000 in 1990.
Rates of non-Hodgkin lymphoma increases steadily with age. Up to 45 years NHL is more common among males than females.

Australia

With over 6,000 people being diagnosed yearly, NHL is the fifth most common cancer in Australia.

Canada

In Canada, NHL is the fifth most common cancer in males and sixth most common cancer in females. The lifetime probability of developing a lymphoid cancer is 1 in 44 for males, and 1 in 51 for females.

United Kingdom

On average, according to data for the 2014–2016 period, around 13,900 people are diagnosed with NHL yearly. It is the sixth most common cancer in the UK, and is the eleventh most common cause of cancer death accounting for around 4,900 deaths per year.

United States

Age adjusted data from 2012-2016 shows about 19.6 cases of NHL per 100,000 adults per year, 5.6 deaths per 100,000 adults per year, and around 694,704 people living with non-Hodgkin lymphoma. About 2.2 percent of men and women will be diagnosed with NHL at some point during their lifetime.
The American Cancer Society lists non-Hodgkin lymphoma as one of the most common cancers in the United States, accounting for about 4% of all cancers.

History

While consensus was rapidly reached on the classification of Hodgkin lymphoma, there remained a large group of very different diseases requiring further classification. The Rappaport classification, proposed by Henry Rappaport in 1956 and 1966, became the first widely accepted classification of lymphomas other than Hodgkin. Following its publication in 1982, the Working Formulation became the standard classification for this group of diseases. It introduced the term non-Hodgkin lymphoma or NHL and defined three grades of lymphoma.
NHL consists of many different conditions that have little in common with each other. They are grouped by their aggressiveness. Less aggressive non-Hodgkin lymphomas are compatible with a long survival while more aggressive non-Hodgkin lymphomas can be rapidly fatal without treatment. Without further narrowing, the label is of limited usefulness for people or doctors. The subtypes of lymphoma are listed there.
Nevertheless, the Working Formulation and the NHL category continue to be used by many. To this day, lymphoma statistics are compiled as Hodgkin's versus non-Hodgkin lymphomas by major cancer agencies, including the US National Cancer Institute in its SEER program, the Canadian Cancer Society and the IARC.