Hodgkin’s Lymphoma; the race is on to find a cure
Hodgkin’s lymphoma (HL) or cancer of the lymphatic system is a type of haematological cancer affecting the lymphocytes within the blood stream. The disease was found in 1832 and has been named after Dr Thomas Hodgkin an English pathologist that described abnormalities within the lymphatic system (LS) which leads to the progression of the disease from a single lymph node to another alongside systemic symptoms with progressive disease. Lymph nodes (LN) are the sites of Lymphocyte production hence HL can inaugurate in any part of the LS from lymph nodes to lymph vessels across the body although the more common initiation position is within the neck followed by the lymph nodes within the axilla (under the arms), in the chest and within the groin. There are 500-600 lymph nodes present in an adult with half of that placed within the abdominal cavity. They are essential to prevent infections, drain fluids from the arms and legs. Molecules within bacteria or bacterial antigens may be taken up by dendritic cells into the LS and LN where the lymphocytes produce an antibody in response to the pathogenic antigen and will be released into circulation which will destruct the foreign body via a specific pathway known as the complement pathway. LNs more commonly may be felt across the body during the presence of an infection due to the increased production of immune cells. However, the same lymphocytes that are a defence mechanism within the immune system may also can be transformed to cancerous cells and so begins the story of HL.
There are 2 main types of Lymphomas; HL and non-HL (NHL) with the more common being NHL with 1 in 5 being HL. According to current statistics 1 just over 1 in 10 people are diagnosed with HL in the liver, bone or lung and 1 in 3 in their spleen. The cause of HL is the same as those of cancer; age and gender, previous NHL, lowered immunity, contact with common infections, Epstein Barr virus, Hepatitis C virus, hair dye, chemicals, alcohol, smoking, being overweight and family history. HL may occur at any age although its more common in the teens with a peek between 15-29 year olds with this form of cancer being the 3rd most common type within this age group. Studies also suggest HL is slightly more common in men than women and also in those that have been treated for NHL previously mainly due to the treatment they had for HL. Those individuals with a an impaired immune system such as those with HIV or AIDS, taking medication to prevent organ rejection post transplantation, develop an auto-immune conditions such as rheumatoid arthritis or systemic lupus erythematosus and those with rare genetic immune diseases are also at high risk at developing HL. HIV or AIDS patients have a risk of 11 times greater at developing HL than the general population followed by those that have had organ transplantation. Epstein Barr Virus which causes mononucleosis or glandular fever may affect individuals for a long time thus increases the chances of developing HL although the exact process by which it does so in unclear. First degree relatives such as brother, sister, parent, child of HL patients have an increased risk of developing HL although the cause is unclear it is speculated to be inherited gene change or shared life style factors. Identical twins are also 100 times more likely to develop HL during their life time compared to the general population while non identical twins have the same risk as any other individual within the general population. Several studies across Europe have also shown that the use of hair dyes may increase the risk of developing HL. Chemicals such as pesticides and some types of solvents that are used as part of a work regime may also increase the risk of HL and this has been shown across the globe by disasters such as Chernobyl in Russia and PG&E power plant’s use of chromium in the USA. Several studies conducted across Europe for the European study called EPIC have also shown a link between smokers and development of HL. HL risk also increases amongst obese men and not women.
Symptoms underlying HL may be fatigue, weight loss, high temperature, night sweats, itching, being short of breath, bruising easily, constant infections, bone or nerve pains, abdominal pains, enlarged spleen or lymph nodes and lymph nodes are more than 2cm wide and have been so up to 6 weeks. However, bear in mind these symptoms are common amongst less serious medical conditions thus does not always mean an individual may have HL. Guidelines for children however are different; an enlarged spleen and liver or a mass in the chest (visible in an X-ray), lymph nodes are firm or hard and not sore to the touch, larger than 2cm across in the arm pit or collar bone and shortness of breath must be seen by a physician as soon as one or more symptoms become apparent.
If HL cells are present within a biopsy other tests such as blood tests to determine serum albumin, ESR (Erythrocyte sedimentation rate) and LDH (Lactic dehydrogenase) is also required as these are prognostic factors which may indicate how an individual may respond to treatment. Chest X-rays are required to observe the presence or absence of enlarged lymph nodes within the mediastinum or the middle part of one’s chest cavity. This determines the type of treatment one requires and may also indicate the presence or absence of pleural effusion or fluid collection around the lungs although this may be rare in HL. For those individuals diagnosed with HL using a biopsy a CT or MRI scan is also required to observe the presence or absence of enlarged lymph nodes around the body. PET scan may also be required to determine if the impending enlarged lymph node is scar tissue or lymphoma and this may also be used during treatment to ensure the patient is responding to the treatment. A joint PET-CT may also be done on patients of HL to observe the areas of the body with over active cells, activity and changes of cells within the body. Some HL patients may also be required to do a bone marrow test to observe the presence or absence of HL cells as this effects the treatment the patient may need. Patients may be subjected to other tests but will be varied amongst each patient.
The above information will be used to stage and decide the best treatment for the disease. HL comprises of 4 stages with stage 1 being the presence of HL only in a single group of lymph nodes or in an organ. Stage 2 means the presence of HL in 2 or more groups of lymph nodes or an organ and 1 or more group of lymph nodes with both sites being on the same side of the body while stage 3 the presence of these elements on both sides of the body. Stage 4 is when HL hasn’t been contained into a single compartment of the body, it has spread to organs such as the liver, bones and lungs along with multiple groups of lymph nodes. Stages 1 and 2 are collectively known as early stage HL without the presence of the bulky disease and favourable factors are present for these patients. Stage 3 and 4 are known as advance disease thus unfavourable conditions for treatment due to modifying features such as bulky disease, lymphoma outside of the LS, low serum albumin, low red blood cells, higher number of leukocytes and a low number of lymphocytes.
There are many different types of treatments available of HL patients although the 3 main types are radiotherapy, chemotherapy, bone marrow or stem cell transplant and steroids. The treatment of HL is successful in most cases with 80% of patients having a 5 year survival rate. However, the outcome of the treatment is dependent upon the stage of the HL, thus if the disease was discovered in its foetal stages along. The type of HL is also important in the treatment of the disease as some may have better treatment options than others.
