Lymphomas are a group of cancers originating from the lymphatic system, a crucial component of the body's immune defence against foreign substances, infections and diseases. These cancers arise when lymphocytes, a type of white blood cell, proliferate uncontrollably. Lymphomas are broadly classified into Hodgkin lymphoma (formely known as Hodgkin's disease) and non-Hodgkin lymphoma, each with distinct spread patterns, effects on the body and responses to treatment. Lymphoma is the third most common cancer in children.
Hodgkin lymphoma is identified by the presence of abnormal Reed-Sternberg amidst lymphocytic infiltration. Epstein-Barr virus infection, autoimmunity and immunodeficiency are implicated factors in its development. It exhibits a bimodal age distribution, with early peaks in the mid to late 20s and a later peak post-50 in developed countries, while in developing countries, the early peak often occurs before adolescence.
Childhood Hodgkin lymphoma types:
More prevalent in children under 10 years, non-Hodgkin lymphoma encompasses three primary types: mature B-cell lymphoma, precursor lymphoid lymphoma and mature T-cell lymphoma.
Comprising about 40% of paediatric non-Hodgkin lymphoma cases1, this type typically presents with enlarged lymph nodes in the throat, neck or abdomen. It may be found in the bones or bone marrow. There are 3 major subtypes:
It can affect the bones, bone marrow and the mediastinum, potentially spreading to the lungs, heart sac and distant organs such as the kidneys. It's more common in older adolescents.
Making up about 30% of non-Hodgkin lymphoma in children1, this can manifest as swollen lymph nodes or a significant mediastinal mass.
When more than 25% of bone marrow comprises blasts, it is classified as acute lymphoblastic leukaemia (ALL).
While rare, mature T-cell lymphomas like anaplastic large cell lymphoma (ALCL) and peripheral T-cell lymphoma (PTCL) can involve lymph nodes, bones and organs. ALCL is responsible for about 10% of childhood non-Hodgkin lymphoma2 and may present with skin rashes or lumps, rapid growth and severe systemic inflammation.
1Principles and Practice of Paediatric Oncology (7th Edition),
2American Cancer Society
The exact cause of lymphoma in children remains unknown. However, there are certain risk factors that increase susceptibility:
Lymphoma can manifest in various forms, making early diagnosis challenging. Symptoms might not be evident until the disease has progressed significantly
Hodgkin lymphoma symptoms:
Non-Hodgkin lymphoma symptoms:
Indicators of possible lymphoma:
Due to these varied symptoms, lymphoma is often initially misdiagnosed. For example, a child with fever and cough might be treated for tuberculosis, or abdominal pain might be mistaken for constipation, delaying the correct diagnosis of lymphoma.
Led by a paediatric oncologist, the team at NUH designs a comprehensive treatment plan, beginning with a detailed history and physical examination to understand the child's symptoms and their progression.
Chemotherapy, which is central to lymphoma treatment, employs powerful medications to destroy or inhibit the growth and division of cancer cells. These medications are typically administered intravenously, but some are oral. Combination therapy, using various medications simultaneously, is common, with treatment duration depending on the cancer's type and stage.
For queries about chemotherapy and potential side effects such as hair loss and fertility issues, please consult your paediatric oncologist.
Radiation therapy employs high-energy X-rays or other types of radiation to target cancer cells. In young children, it can affect bones and soft tissue growth and may increase the risk of heart disease and secondary cancers later in life. It is less commonly used in treating Hodgkin lymphoma in children.
Lymphoma usually spreads throughout the lymph system, negating the presence of a specific tumour site. However, if there is a significant accumulation of lymphoma in one area, surgery to remove the tumour may be considered.
Increasingly utilised for advanced or treatment-resistant lymphomas, targeted therapy attacks specific substances essential for cancer growth wile sparing normal cells. Examples include using Brentuximab, an anti-CD30 antibody-drug conjugate targeting CD30 on lymphoma cells, and Crizotinib, an anti-Anaplastic Lymphoma Kinase (ALK) inhibitor used in high-risk ALK-positive ALCL cases.
Crizotinib, an anti-Anaplastic Lymphoma Kinase (ALK) inhibitor, is used as upfront therapy to target ALK-positive ALCL for high-risk cases.
For hard-to-treat lymphoma or recurrence after chemotherapy, high-dose chemotherapy followed by an autologous stem cell transplant (using the child's own stem cells) may be proposed. The child's stem cells are harvested, stored and later infused back into their body.
In certain situations, an allogeneic transplant (using a donor's stem cells) may be required, particularly if the child's lymphoma relapses or does not respond to an autologous transplant.
Effective follow-up care is a vital aspect of treatment for children with lymphoma. The frequency of follow-up visits depends on the type of cancer and the treatments used. Children undergoing treatment may need follow-up checks as often as weekly or as infrequently as monthly.
After treatment completion, follow-up care continues. Typically, visits are scheduled every three months for the first year, biannually for the second year and then annually thereafter.
These visits may include blood tests and imaging tests like PET-CT scans to monitor for lymphoma recurrence. Additionally, late effects of cancer treatment will be assessed, including growth and hormone disturbances and organ function issues in the liver, kidneys, lungs and heart.
Hodgkin Lymphoma generally has a more favourable prognosis compared to non-Hodgkin Lymphoma. Non-Hodgkin lymphoma outcomes can vary significantly due to the diverse types and biological characteristics of the disease, impacting treatment response. The five-year survival rates for non-Hodgkin lymphoma range from 45–87%, while early-state Hodgkin's lymphoma sees survival rates around 95%3.
9a Viva-University Children's Cancer Centre, the five-year survival rate for treatment-naïve Hodgkin Lymphoma is 100%, and 88.5% for non-Hodgkin lymphoma. However, survival rates for relapsed patients, especially those with non-Hodgkin lymphoma, remain lower, indicating a need for further research in this area.
Information is correct as of September 2017.
Source: 3National Cancer Institute
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