Hodgkin’s lymphoma

Classification according to ICCC: II.a (Hodgkin lymphomas)

Definition

Hodgkin’s lymphoma (HL) develops from a malignant transformation of B-lymphocytes in lymph nodes. Reed-Sternberg cells or their precursors (the so-called Hodgkin cells) are considered to be malignant. In the cancerous tissue, these malignant cells are surrounded by large numbers of reactive lymphocytes and histiocytes.

Occurrence

Hodgkin’s lymphoma (HL) accounts for 8% of childhood cancers. It is rare in preschool children: the incidence rate is about 1 case per 1 million children in this age category. The incidence peaks at the ages of 15–19 (with incidence rates of about 32 cases per 1 million teenagers in this age category). Incidence rates are approximately equal in boys and girls.

Symptoms

The disease affects lymph nodes at first, spreading to organs later (spleen, liver, lungs, bones). Painless enlargement of lymph nodes, typically cervical or supraclavicular ones, is a typical symptom of Hodgkin’s lymphoma. Intrathoracic lymph nodes are enlarged in more than a half of patients, potentially leading to cough, back pain, and later even dyspnoea as a result of compression of the respiratory tract. Approximately one third of patients show unspecific symptoms (the so-called B-symptoms: temperature above 38 °C of non-infectious origin, weight loss exceeding 10% over the last 6 months, night sweats), and their presence is linked to a poorer prognosis. Itching of the skin is a rare symptom.

Diagnosis

Painless, progressively enlarging cervical or supraclavicular lymph nodes are a typical symptom of Hodgkin’s lymphoma. Advanced Hodgkin’s lymphoma is characterised by an enlarged spleen, which is penetrated by lymphoma foci (as seen on an ultrasound image). Some children have visible scratching marks as a result of persistent itching of the skin. Laboratory tests show a high sedimentation rate, and the blood count is characterised by anaemia and leucocytosis. Biochemical examination might show increased levels of immunoglobulins, lactic dehydrogenase (LDH), and C-reactive protein (CRP). Biopsy from the affected tissue (typically from an enlarged lymph node) is essential in order to establish the diagnosis exactly. PET-CT scan is a standard imaging technique that is needed to determine the extent of the disease and to assess the treatment response.

Classification

The current WHO classification of lymphoid neoplasms distinguishes two types of Hodgkin’s lymphoma: nodular lymphocyte-predominant Hodgkin’s lymphoma (NLPHL), and classic Hodgkin’s lymphoma (CHL). Classic Hodgkin’s lymphoma is classified into four histopathological subtypes (nodular sclerosis, lymphocyte-rich, mixed cellularity, lymphocyte-depleted).

Therapy

Hodgkin’s lymphoma is the most easily curable cancer in children. Treatment is based on a combined chemotherapy, followed by a subsequent irradiation of affected lymph nodes. The intensity and duration of chemotherapy are determined by the extent of the disease, as well as by the presence of B symptoms.

The increasing percentage of cured children inevitably leads to a growing number of serious late effects of treatment (development of secondary cancers, more frequent occurrence of valvular heart disease and atherosclerotic changes in irradiated areas, increased risk of early menopause). The current treatment guidelines therefore limit the use of alkylating agents, and eliminate radiotherapy in children who have a good response to the induction chemotherapy.

Treatment outcomes

The chance of being cured is almost 100% in children with localised HL, and more than 90% in patients with advanced HL.

Role of general paediatrician

The general paediatrician should think about the possibility of Hodgkin’s lymphoma not only in patients with persistent lymphadenopathy in the cervical or supraclavicular area, but also in children suffering from chronic cough and breathing problems, and in cases of fever of non-infectious origin. The diagnosis itself is ensured by a haemato-oncological centre.

In the course of treatment, the general paediatrician cooperates with the centre and follows up the patient. He/she has also an important role in distinguishing potential late effects of treatment. Upon treatment completion, the vaccination of paediatric patients is performed in vaccination clinics.