NHL originates in white blood cells, known as lymphocytes. Lymphocytes are an essential component of the immune system that helps the body to fight infections and other diseases.
The two main types of lymphocytes are T lymphocytes and B lymphocytes. Although tumors can develop in either, B-cell lymphomas are much more common in the United States than T-cell lymphomas (Howlader et al., 2014). B-cell lymphomas represent approximately 85% of all cases in the United States (Nogai et al., 2011).
According to The American Cancer Society (2017), there will be 72,240 new cases of NHL and 20,140 deaths associated with NHL; it is on the list as one of the most common types of cancer diagnosed in the United States. NHL is a heterogeneous disease resulting from the malignant effect on both B and T lymphocytes as well as natural killer (NK) lymphocytes, in rare cases. Lymphomas involving the B-cells have the ability to arise from any maturation point in the cell’s development. The median age of onset is approximately 60 years and is believed to continue to increase in the future. In review of all combined subtypes, survival rates at one year for men and women are greater than 70% while the five-year survival rate is above 60% (American Cancer Society, 2017). As NHL diagnoses increase globally, the importance for more research is necessary.Risk Factors Non-Hodgkin lymphoma comprises a group of closely related yet heterogeneous diseases, each characterized by the malignant transformation of lymphoid cells but with distinctive morphologic, immunophenotypic, genetic, and clinical features (Zelenitz, 2010).
B and T lymphocytes, the most commonly affected white blood cells, are involved in cellular and humoral immunity in our bodies. Cellular immunity, also known as cell-mediated immunity, is an immune response that does not involve antibodies, but instead involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes and the release of various cytokines in response to an antigen (King and Myatt, 2014). Humoral immunity is provided by the antibodies present in the body. Lymphocytes are found in the lymphatic system which is made up of lymph, lymph vessels and lymph nodes. A focus of current research in NHL is establishing modifiable factors that prove to increase the risk of being diagnosed with NHL. However, the majority of the research work has been on comparison of different treatment modalities and protocols to alter or create the most effective disease treatment with the least amount of damage to the host.
Modifiable risk factors are an aspect of the trending research in NHL that nurses have the ability to affect through education. Many people are attuned to the common risk factors of cancer such as smoking, which is responsible for 28 percent of all cancer deaths (Ng et al., 2014). However, when reading literature on the NHL’s risk factors, some are not as mainstream, but can be modified through awareness and education. One of these risk factors pertains to one’s diet. Yang et al. (2015) found that there is a positive correlation between both red meat and processed meat and NHL. High intake of red meat and processed meat versus low intake was found to increase risk of NHL by 32 percent and 17 percent, respectively.
Mozaheb et al. (2012) had confirming findings to that of Yang et al., however, they studied specific types of red meat as well as how each differed in correlation with NHL. These studies concluded that the meat with the highest risk for development of NHL, was ground beef. Ground beef is of higher risk, because the meat is processed and grilled at high temperatures, generating carcinogens and mutagens (such as heterocyclic amines); “it has been shown that these compounds can induce immunotoxicity and lymphoma” (Mozaheb et al., 2012).
Another component found in processed meat that makes it a danger is nitrite, which is used to fight Clostridium botulinum as an antibacterial agent. Nitrite is also used to create the familiar pinkish color of cured meats. When nitrites and nitrates react “with secondary amines and N-alkylamides, a process that can occur endogenously… they can become human carcinogens” (Abid et al., 2014).Although many research projects have established similar findings on correlations between high intake of red meat and NHL, there needs to be more specific and consistent parameters in quantifying red meat consumption.
For example some studies measured intake in grams per day, while others measured consumption in portions per month. There was also inconsistency in what high intake constituted as studies differed in their methodology. For instance, Mozaheb et al. (2012) used a questionnaire that consisted of a 9-point system for how often a subject consumed that specific food.
They established the highest score to be “consuming meat once per week.” This appears to be very different than Abid et al. who found that Americans consume 3.7 pounds per week.
Although difficult to establish, studies should attempt to follow one universal system of intake values to find reliability among studies. Another concern with research of this nature is basing findings on subjective data. With this kind of research, findings can be skewed by dishonesty, memory, and even mood of subject during interview. Lastly, Mozaheb et al. had a fairly small sample size (170 patients, 190 controls) which might make one question the results however, Yang et al. (2015) compiled a dataset of 15,189 subjects diagnosed with NHL. This is a substantial sample that helps validate the results of the aforementioned study. Lastly, there is the possibility of the publication bias in these findings.
Many studies that found negative correlations between red meat and NHL may not have been published. With these findings becoming more and more prevalent, those people who have nonmodifiable risks must be educated on actions they can take in prevention. Diet findings prove to be a key component of creating some semblance of control for limiting one’s risk for NHL. People at increased risk should be educated on healthy protein options such as chicken and/or fish and different cooking techniques that are less harmful in generating mutagens and carcinogens such as broiling as opposed to grilling or pan-frying.
The Healthy Eating Plate recommends that people “limit red meat, and avoid processed meats such as bacon and sausage.” (Healthy Eating Plate, 2014). Advice from the American Institute for Cancer Research is similar and goes a bit further, suggesting that to reduce cancer risk, people should “eat no more than 18 ounces (cooked weight) per week of red meat,” while completely avoiding processed meat (Cancer Institute, n.d.
). These nutritional guidelines not only should be taught to high risk patients, but also need to be taught to our youngest generation to provide insight about the risks involved in our dietary choices. Through education and raising awareness about the risk diet plays in developing NHL, nurses have an opportunity and a responsibility to stay current with research and incorporate related information in health education with their patients. Health classes need to add curriculum on the risks of dietary choices in terms of cancer and heart disease, and not only in terms of obesity. The United States is the second leading country in the world in consumption of red meat, and it is our responsibility as nurses to educate on the implications of this dietary choice.Future research should be focused on the weaknesses presented in the analysis. Studies need to attempt to establish consistent guidelines for quantifying red meat consumption, the definition of red meat and the different categories.
The uniformity will create clear cut findings that can be analyzed against other similar literature. Currently, a meta analysis on this topic would be profoundly difficult. There should also be research focusing on new trends such as “organic” and “grass fed” red meat to examine if these have any benefits in decreasing the risk of NHL. It would be interesting due to pesticides and fertilizer which is a known environmental risk factor of NHL cannot be consumed by cows that are certified as organic.There are other modifiable risk factors concerning NHL including viral infections. One of the most known virus infections linked with NHL is the Epstein-Barr virus. The Epstein-Barr virus is part of the family of the herpes virus that infects more than 95% of the adult population worldwide.
The infection is acquired in early childhood and continues lifelong in a latent state in memory B lymphocytes (Sinha, et. al 2016). The “virus can be transiently reactivated in response to physical or psychological stressors” (Roos et. al, 2013). In poor-controlled EBV infections in NHL, the B-cell proliferation induced by EBV seems to increase the pool of B cells, affecting the risk where mutations can occur.A study by Roos et.
al (2013) supports possible evidence of poor-controlled EBV infections of increasing the risk of NHL. The study used 491 cases of women with NHL to explore the potential causative factor of Epstein-Barr virus. EBV serum samples were collected; IgG antibodies and several EBV-encoded antigens like EBNA1 and EA-D were analyzed. “Women who were seropositive for IgG to EBNA1 were at decreased risk of developing B-cell NHL” and “seronegativity to EBNA1 was associated with increased risk” (Roos et.
al, 2013). While there was no definite association between the level of antibody to EBV antigen and risk of NHL, there was a possible association between poor control of EBV infection and cause of certain NHL subtypes. However, the sample size was not large enough to conclude that there is no evidence of a causal relationship between the EBNA1 antigen and NHL. The results do indicate that the Epstein-Barr virus is a risk factor, no matter how small the impact may be.In developing countries, the Epstein-Barr virus and Non-Hodgkin lymphomas are prevalent and multiple studies have been conducted to detect the presence of EBV in NHL individuals. For example, in two studies, Pakistani and Iran populations were used to determine the frequency of EBV in NHL. According to one study, Ishtiaq et.
al (2013), “the expression of Epstein-Barr virus in Non-Hodgkin’s lymphoma can be identified by immunohistochemistry for detecting of Epstein-Barr virus latent membrane protein (LMP).” With high levels of latent membrane protein, the EBV has played its role as an etiologic agent in the development of NHL. A Pakistani population of 71 cases were used in the study. The age, gender and type of lymphoma (whether T-cell or B-cell lymphoma) were varied with the individuals. Results showed that the LMP-1 marker was positive in 12.
7% cases and negative in 87.3% cases. Ishtiaq et. al (2013) used a Hodgkin lymphoma case as the “control since the expression of LMP-1 EBV is higher in Hodgkin lymphoma patients (70%) than in NHL patients (30%). The overall EBV expression among the participants in the study was 12.
7%, EBV positivity for B-cell lymphoma was in 11.1%, and positivity for T-cell lymphoma was in 25% of the cases. To conclude this study, the “frequency of EBV in NHL is 12.7% and mostly seen in diffuse large B cell lymphomas” (Ishtiaq et. al, 2013). Having a control case to compare the results was a valuable idea, yet the sample size was too small to be compared to. The participants of all ages and gender were varied, as opposed to the first study mentioned above which only included 491 women; this gave more results to work off on. On the other hand, the Abadi et.
al (2013) study involving 34 cases of Iran individuals showed 26.5% immunocompromised participants with NHL had EBV and EBV positivity was more prevalent among T-cell lymphomas. This contradicts the Ishtiaq et. al (2013) study, but proves that EBV can be present in either lymphoma.
With the Epstein-Barr virus as an established modifiable risk factor, education is key for nurses and their patients. As mentioned above, diet is an important factor to consider when dealing with viral infections. With the proper diet and treatment, the immune response can be boosted in order to fight off the virus. Nurses should take note of what their patients eat, give the proper medications and care that these people with EBV or NHL need. Risk can be decreased greatly for those with EBV if it is well controlled. However, it is difficult for those who live in poorly-developed countries as they do not have the proper resources.
An interesting environmental risk factor that has been correlated to the development of NHL is women who have used hair dye before 1980. Bassig and colleagues aimed to examine the interaction between variants in DNA repair genes and hair dye use with risk of NHL in a