Cancer is expected to rank as the leading cause of death and the single most important barrier to increase life expectancy in every country of the world in the 21st century. According to estimates from the World Health Organization (WHO) in 2015, cancer is the first or second leading cause of death before age 70 years in 91 of 172 countries, and it ranks third or fourth in an additional 22 countries [1]. There were an estimated 18 million cancer cases around the world in 2018, of these 509,590 Non-Hodgkin lymphoma cases, contributing 3% of the total number of new cases diagnosed in 2018, and ranking 12th among the most common cancers worldwide, and 79,990 Hodgkin lymphoma cases contributing 0.5 % of the total number of new cases diagnosed in 2018, and ranking 26th worldwide [2]. Lymphoma is a group of blood cancers that begins in infection-fighting cells ofthe immune system, called lymphocytes (a type of white blood cell). These cells are in the lymph nodes, spleen, thymus, bone marrow, and other parts of the body [3]. There are so many subtypes of lymphomas [4]. Lymphoma is broadly classified as either Hodgkin's lymphomas (HL) or non-Hodgkin lymphomas (NHL) about 90% of lymphomas are non-Hodgkin lymphomas [5]. Signs and symptoms may include enlarged lymph nodes usually painless, fever with no evidence of infection, drenching sweats most commonly at night, unintentional significant weight loss, itching, and fatigue [6,7].
The cause of lymphoma is unknown, but there are possible factors that could contribute to the development of lymphoma. Risk factors for Hodgkin lymphoma include infection with Epstein-Barr virus and a history of the disease in the family, weakened immune system, and tobacco smoking [6,8]. Risk factors for common types of non-Hodgkin lymphomas include autoimmune diseases, HIV/AIDS, infection with human T-lymph tropic virus, immunosuppressant medications, and some pesticides [7,9]. Eating large amounts of red meat may also increase the risk [10,11].

To study the trends of lymphoma incidence among patients registered in Dubai hospital for the period 2008-2016, and to study some socio demographic characteristics of the admitted cases.

Dubai hospital cancer registry is population-based registry founded in 2005 the main objectives of the cancer registry are to record the annual incidences of all cancers, overall and by gender and to observe cancer incidence trend changes. The cancer registry covers the cancer patients in Emirate Dubai, including all local and expatiates population groups approximately 3.137 million. Cancer cases are identified by the registry through active data collection methods, where the patients whom treated in Dubai Health Authority only registered in Dubai hospital cancer registry. Data are entered into a secure registry database according to coding standards of the international classification of disease for oncology. The ethical approval was obtained from the research committee in Rashid hospital in order to access the data in cancer registry. The data were obtained retrospectively through hematology department registry Unit in Dubai Hospital for the period 2008 -2016, records has been revised. All cases were confirmed and treated in Dubai hospital, all admitted cases were included in the data analysis, they were both male and females, all age groups and all nationalities, and diagnosed and confirmed cases by Histopathological studies were considered only. The data were coded no names, medical record number, and contact details were shown in the current study.

The current study showed that the incidence rate of lymphoma among Emirati female was 0.06/1000 in 2008, while it was 0.02/1000 among male emirate in the same year. After that there was a noted variation in the incidence rate between male and female emirate over the years; for Emirati female there was a sharp decline to 0.02/1000 in 2009 and 2010, then increased gradually to be again 0.06/1000 in 2013, then sharp decline to 0.01/1000 in 2015 then finally increased to 03/1000 in 2016 as for emirate male, in 2009 there was 0.03/1000, in 2010 there was no cases of lymphoma, then after that there was 0.04/1000 and 0.05/1000 in 2011 and 2012 respectively, and then decreased to be 0.02/1000 in 2014, and finally increased to be 0.04/1000 in 2016 [Figure 1]. Among non-locals, the present study showed that the incidence rate of lymphoma among non-emirate female admitted to Dubai hospital was 0.05/1000 in 2008, and the incidence kept steadilyuntil 2016.Between 2008 and 2016 there was some variations in the incidence rate among non-emirate female. As for non-emirate male, the incidence rate was 0.10/1000 in 2008 which was decreasing sharply to become 0.02/1000 in 2009, which means lower than the incidence rate of non-emirate female in that year, then started to increase to 0.11/1000 in 2011, and since then the incidence rate among non-emirate male was constantly higher than the incidence rate among non-emirate female over the years to be finally 0.14/1000 in 2016 [Figure 2].In term of nationality, the present study showed that the incidence rate of lymphoma among non-Emirate admitted to Dubai hospital was constantly higher than the incidence rate among Emirate; the incidence rate of lymphoma among non-Emirate admitted to Dubai hospital was 0.07/1000 in 2008, after that it was fluctuating over the years to reach the highest incidence rate 0.14/1000 in 2013, and finally 0.09/1000 in 2016. Among Emirate, the study showed that the incidence rate was 0.04/1000 in 2008, after that there was a slight variation in the incidence rate over the years and ended with the same incidence rate 0.04/1000 in 2016 [Figure 3]. The current study showed that the overall incidence rates of lymphoma cases registered in Dubai hospital per 1000 of the registered patients was constantly higher among males than females except in 2009 and 2010. It was lower among males than females, since it was 0.06/1000 among males in 2008, then decline to 0.02/1000 in 2009 and 0.04/1000 in 2010 and continued to increase to 0.08/1000 in 2011 and then fluctuating to be finally 0.09/1000 in 2016. While the total female incidence rate oflymphoma registered at Dubai hospital showed between 0.05/1000 in 2008, rising up to 0.08/1000 in 2014 and finally 0.04/1000 in 2016 [Figure 4].

The current study revealed that the incidence and trends was stable across years during the period 2008 to 2016, to be the fifth most common cancer in 2016 after breast cancer, leukemia, colon cancer, and thyroid cancer among patients admitted to Dubai Hospital [12]. Which is comparable to the findings from other studies in Saudi Arabia and Iraq and from neighboring countries [13,14]. In Jordan lymphoma was the fourth most common cancer among Jordanians both genders in 2012 [15]. In Saudi Arabia in 2012 non-Hodgkin lymphoma (NHL) was the fifth most common cancer and Hodgkin lymphoma (HL) was eighth most common cancer [16]. In Oman NHL was the fifth most common cancer in 2012 [17]. But when we compare our results to western countries, the incidence rate is higher than western countries and globally; in US lymphoma was the seventh most common cancer in 2017 among males only, and for the incidence trends, the overall incidence rates for both HL and NHL were stable from 2004 2013 [18].In Australia lymphoma was the 6th most commonly diagnosed cancer in 2014. It is estimated that it will remain the 6th most commonly diagnosed cancer in 2018 [19]. Present study showed that the incidence rate of leukemia is more among males population comparing to females groups, which is similar to the results of other studies in other countries and globally [2,12-19]. Andthe incidence rate of leukemia is more among expatriate groups comparing to Emeriti national groups of population, which is no wonder in that since the percentage of expatriate is much higher 88.5% [20]. In regard to prevention of lymphoma, there are a number of risk factors for lymphoma that can't be modified, such as age or sex. There is no guaranteed way to prevent lymphoma. Most people have no risk factors that can be changed, so there is no way to protect against these lymphomas. But there are some ways that might lower the risk for lymphoma, such as limiting the risk of certain infections and maintain a healthy immune system; Infection with HIV, the virus that causes AIDS, is known to increase the risk of NHL, Preventing the spread of the human T-cell lymphotropic virus (HTLV-1) could have a great impact on non-Hodgkin lymphoma, so one way to limit your risk is to avoid known risk factors for HIV, such as intravenous drug use or unprotected sex with many partners [21,22]. Helicobacter pylori (H.pylori) infection has been linked to some lymphomas of the stomach. Treating H. pylori infections with antibiotics and antacids may lower this risk. Some lymphomas are caused by treatment of other cancers with radiation and chemotherapy or by the use of immune-suppressing drugs to avoid rejection of transplanted organs [21]. Some studies have suggested that obesity may increase the risk of non-Hodgkin lymphoma. Other studies have suggested that a diet high in fat and meats may raise the risk. Staying at a healthy weight and eating a healthy diet may help protect against lymphoma [23]. Another risk factor for HL is infection with the Epstein-Barr virus (the cause of infectious mononucleosis, or mono), but there's no known way to prevent this infection [22]. Cigarette smoking also considered one of the modifiable risk factors for HL [24]. As well as exposure to tobacco smoke and active smoking may increase the risk of follicular lymphoma [25,26].

The study concluded that lymphoma is more among males compared to females, and among expatriates compared to UAE nationals. The time trends showed stable curve across years during the period 2008 to 2016, to be the fifth most common cancer in 2016. Strengthening cancer registry system should be given a priority. Elimination of risk factors as much as possible is recommended to help reduce the incidence of lymphoma but there is no guaranteed way to completely prevent lymphoma.

Ethical standards has been applied to the best of possible.

All Authors declared that these are no conflict of interest

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Figure 1: Incidence rates and time trends 2008-2016 of lymphoma per 1000 of the Hospital patients in Dubai Hospitals according to Gender among UAE nationals.

Figure 2: Incidence rates and time trends 2008-2016 of lymphoma per 1000 of the Hospital patients in Dubai Hospitals according to Gender among non-locals.

Figure 3: Incidence rates and time trends 2008-2016 of lymphoma per 1000 of the Hospital patients in Dubai Hospitals according to nationality.

Figure 4: overall Incidence rates and time trends 2008-2016 of lymphoma per 1000 of the Hospital patients in Dubai Hospitals among male and female.