Focus on Lymphoma for World Lymphoma Awareness Day 2014
By Dr. Brian Bird
Being diagnosed with lymphoma may be a frightening time for the patient and their loved ones. The language used, tests and scans can seem overwhelming.
Every patient is different and a team of doctors, scientists, pharmacists and nurses will work together to come up with a treatment plan. Remember to call the Irish Cancer Society helpline or drop into the Daffodil Centre in your hospital for support and advice.
Lymphoma is a malignancy of white cells called lymphocytes which are the smart cells or "generals" of the immune system. Lymphoma is vulnerable to treatment with chemotherapy, “smart drugs” and radiotherapy. It is always treatable and frequently curable.
There are many different types of lymphoma. They all tend to involve the lymph nodes and may spread to involve other organs such as bone marrow and liver.
Patients may present with a painless lump in neck, armpit or groin or with complaints of unexplained fever, weight loss over one stone, and drenching night sweats. Surgery is only used to remove a lymph node for diagnosis and cannot cure lymphoma.
Doctors called pathologists and scientists examine thin slices of the lymph node under a microscope and tell clinicians who treat patients what type of lymphoma the patient has. Physical examination, scans and blood tests tell us where it is in the body and how much lymphoma there is – the clinical stage.
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Different types of DLBCL seen down the microscope
The language doctors use to describe lymphoma and the treatments are very different to "solid" tumours such as breast or colon cancer. These tumours are cured by surgery with chemotherapy and radiation helping. Lymphoma cells are very sensitive to chemotherapy and radiotherapy.
Patients have a much better chance of being treated successfully for lymphoma even with advanced or Stage IV lymphoma compared with Stage IV cancer. Most lymphomas arise from a type of lymphocyte called B cells. Only 5% arise from T cells.
Thomas Hodgkin described lymphoma in the mid 1800s and Hodgkin's Disease or Lymphoma is named after him. Hodgkin's Lymphoma (HD) nearly always requires treatment with chemotherapy (and frequently radiotherapy as well) and is cured in the vast majority of patients. Physicians try and give patients the best chance of being cured and to reduce the risk of side effects happening 20-30 years later.
Hodgkin's Lymphoma tends to start in one lymph node and to spread to adjacent lymph nodes in a stepwise fashion. It is common in the late teenage to twenties and peaks again in those aged over 50. Non Hodgkin Lymphomas (NHL) are more complicated.
Some are "low grade" or "indolent" and these may be managed by careful observation or "watchful waiting". These are the types of lymphoma I tell my patients to imagine as "pussy cats" – unlikely to cause much harm but you'd keep an eye on them all the same.
If they cause trouble (fever, weight loss over one stone, swinging fevers) or grow rapidly then we consider using chemotherapy or radiotherapy. Common low grade NHL include Follicular Lymphoma and Small Lymphocytic Lymphoma.
The "tigers" or high grade Non Hodgkin Lymphomas include Diffuse Large B Cell Lymphoma and Burkitt Lymphoma (named after a Trinity graduate ). These require intensive treatment with chemotherapy and frequently radiotherapy as well.
A majority of DLBCL are cured with modern treatments. Mantle Cell Lymphoma (MCL) combines features of high and low grade NHL and is challenging to treat but outcomes and treatments are improving. The incidence of NHL increases with age.
What are the major advances in diagnosing and treating lymphoma?
PET scans
Cancer cells tend to burn sugar much more quickly than normal cells. In a PET scan a special radioactive sugar called FDG which glucose hungry cancer cells can absorb but not digest is injected into a vein in the forearm.
The patient must rest in a warm dark room for 90 minutes. This is to ensure that the muscles or fat don't suck up the radioactive sugar. The FDG emits energy which can be detected using a gamma camera. Lymph nodes which emit radioactivity are called "hot". This tells doctors where the lymphoma is hiding.
PET is generally not used for low grade NHL but is used routinely in HD and high grade NHL at time of diagnosis and completion of treatment to check that the lymphoma has been eradicated. Most patients with a cold end of treatment PET scan are cured.
Not everything that lights up on PET is lymphoma – infections, scar tissue and autoimmune disease can also suck up the FDG.
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2. Antibodies which stick to the lymphoma cell and are used with chemotherapy to increase the chances of cure
Rituximab is used in most NHL alongside chemotherapy. It binds to a target found on most B cells called CD20. When Rituximab (Rituxan) binds to a B cell it makes it vulnerable to chemotherapy and signals the immune system to attack it. Rituximab has increased cure rates in DLBCL by at least 20%. It prolongs remission in FL. There are newer antibodies which bind to CD20 such as Ofatumumab which is used in SLL.
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Rituximab alerts the immune system to destroy the NHL cell
Sometimes a very toxic poison can be glued onto an antibody targeting a lymphoma cell. The combined antibody-toxin is eaten by the lymphoma cell and the toxin destroys the cell. For rare HD patients who are not cured with conventional chemotherapy a new drug called Brentuximab Vedotoxin which uses this approach may be helpful.
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3. Oral targeted agents which turn off a signal or switch which is jammed open in the lymphoma cells
Cells use chemical switches called enzymes to decide whether to reproduce or to die.
Lymphoma cells are addicted to signals which normal cells can cope without. New drugs targeting these signals include idelaselib and ibrutinib. These drugs represent a huge advance in the treatment of low grade NHL especially FL and MCL. Clinical trials will make their role in treating chemotherapy resistant DLBCL clearer.
The myeloma drug Lenalidomide has variable activity in NHL.
4. Bendamustine
This is a great drug for low grade NHL and generally well tolerated by elderly patients. Combined with Rituximab, Bendamustine has excellent activity in FL.
5. Lower dose radiotherapy with tighter fields
Radiation is like an incredibly strong light which punches through the body damaging cells. Healthy cells are better able to repair DNA damage than cancer cells.
Improved techniques and clinical trials showing that lymphoma cells don't need high doses of radiation mean that cure rates have improved while side effects are lessened.
6. Lymphoma Survivorship
Because most patients with lymphoma will live a long time after they complete treatment it's really important that they are helped to recover physically and mentally and live healthy active lives. Some treatments can accelerate aging of heart muscle and coronary arteries.
Patients can protect their hearts by exercising, eating healthily and controlling weight gain. General Practioners play a huge role in aggressively treating high blood pressure and high cholesterol in lymphoma survivors with increased cardiac risk.
Patients should ask their oncologist for treatment summary and lifestyle guidance. The Irish Cancer Society guidelines on healthy diet and exercise to prevent cancer are a great start for patients who have completed lymphoma treatment!
I hope you have found this brief article helpful. Remember that more and more patients are successfully treated for lymphoma with fewer side effects than ever before.
World Lymphoma Awareness Day takes place on Monday 15th of September 2014. If you have any questions about Lymphoma you can contact the National Cancer Helpline on Freefone 1 800 200 700 and speak to specialist nurse.
Dr Brian Bird is a Consultant Oncologist with the Bons Secours Hospital in Cork. Find out more about his work on his webpage. You can also follow him on Twitter @DrHealeyBird.
