cancer is the second most common cause of death after injuries in children >1 yr
cause is rarely known, but increased risk for children with:
chromosomal syndromes (e.g. Trisomy 21)
cancer predisposition syndromes (e.g. Li-Fraumeni syndrome)
prior malignancies
neurocutaneous syndromes
immunodeficiency syndromes
family history
exposure to radiation
chemicals
biologic agents
How common:
leukemias are the most common type of paediatric malignancy (30%) followed by
brain tumours (25%) and
lymphomas (15%)
some malignancies are more prevalent in certain age groups
newborns:
neuroblastoma
Wilms’ tumour
retinoblastoma
infancy and childhood:
leukemia
neuroblastoma
CNS tumours
Wilms’ tumour
retinoblastoma
adolescence:
lymphoma
gonadal tumours
germ cell tumours
bone tumours
unique treatment considerations in paediatrics because radiation, chemotherapy, and surgery can impact growth and development, endocrine function, and fertility
good prognosis: treatments have led to remarkable improvements in overall survival and cure rates for many paediatric cancers (>80%)
Lymphadenopathy
Clinical Features
features of malignant lymphadenopathy:
firm, discrete, non-tender, enlarging, immobile
worrisome location (i.e. supraclavicular or generalized)
abnormal imaging findings or bloodwork
constitutional symptoms
fluctuance, warmth, or tenderness are more suggestive of benign nodes (infection)
others as indicated (e.g. HIV, fungal, toxoplasmosis)
uric acid, LDH, electrolytes
CXR
inflammatory panel (ANA, RF, dsDNA)
biopsy:
if increasing in size; or >2 cm and unclear diagnosis or no response to treatment.
Do early biopsy if supraclavicular or very large single or group of nodes (>3-4 cm)
regional lymphadenopathy (1 body area)
period of observation if asymptomatic
trial of oral antibiotics
ultrasound
biopsy (especially if persistent >6 wk and/or constitutional symptoms)
if supraclavicular lymphadenopathy: CXR to rule out mediastinal mass
Leukemia
Epidemiology
mean age of diagnosis 2-5 yr but can occur at any age
heterogeneous group of diseases
ALL (80%)
AML (15%)
CML (<5%)
children with DS are 15 times more likely to develop leukemia
Clinical Features
infiltration of leukemic cells into bone marrow results in bone pain and bone marrow failure
anemia
neutropenia
thrombocytopenia
infiltration into tissues results in
lymphadenopathy
hepatosplenomegaly
CNS manifestations
testicular disease
fever
fatigue
weight loss
bruising, and easy bleeding
investigations:
CBC and differential
Anemia & Thrombocytopenia
variable WBC (most often cytopenias + blasts)
increased leukocytes >100 x 10⁹/L (occurs in 50% of patients);
peripheral blood smear
uric acid
LDH
extended electrolytes
renal function, and blood culture
CXR: patients with ALL may have a mediastinal mass
CT C/A/P and testicular ultrasound to screen for extranodal disease
specialized tests:
BM ± lymph node biopsy
flow cytometry
cytogenetics
molecular studies
hyperleukocytosis (total WBC >100 x 10⁹/L) is a medical emergency
presents clinically with respiratory or neurological distress caused by hyperviscosity of blood and leukostasis
risk of ICH, pulmonary leukostasis syndrome, tumour lysis syndrome
management:
fluids, allopurinol/rasburicase
fresh frozen plasma/platelets to correct thrombocytopenia
induction chemotherapy, avoid transfusing RBCs unless symptomatic (and then use very small volumes)
Management
combination chemotherapy using non-cross resistant chemotherapy agents, allogeneic stem cell transplantation for particular genetic subtypes, poorly responsive disease, or recurrent disease
supportive care and management of treatment complications
febrile neutropenia
tumour lysis syndrome
Prognosis
80-90% 5-yr event-free survival for ALL
50-60% 5-yr survival for AML
patients are stratified into standard risk and high-risk based on WBC and age; other prognostic factors include presence of CNS/testicular disease, immunophenotype, cytogenetics, and initial response to therapy (most important prognostic variable)
Lymphoma
Epidemiology
Hodgkin lymphoma: incidence is bimodal, peaks at ages 15-34 and >50 yr
non-Hodgkin lymphoma: incidence peaks at 7-11 yr
B symptoms
Fever
night sweats
weight loss
subtypes
A = absence of B-symptoms
B = presence of B-symptoms
Clinical Features
Hodgkin lymphoma
most common presentation is persistent, painless, firm, cervical or supraclavicular lymphadenopathy
can present as persistent cough or dyspnea (secondary to mediastinal mass) or less commonly as splenomegaly, axillary, or inguinal lymphadenopathy
constitutional symptoms in 30% of children
lymph nodes become sequentially involved as disease spreads
non-Hodgkin lymphoma
includes most commonly mature B cell lymphoma (Burkitt, diffuse large B cell), lymphoblastic, and mature T cell lymphoma (anaplastic large cell)
rapidly growing tumour with distant metastases (unlike adult non-Hodgkin lymphoma)
signs and symptoms related to disease site: most commonly abdomen, chest (mediastinal mass), head and neck region
investigations:
CBC and differential, peripheral blood smear, extended electrolytes, uric acid, LDH, renal function, liver enzymes and function, ESR, and blood culture if concerns for infection.
CXR and CT of neck/chest/abdomen/pelvis. S
BM aspirate and biopsy ± LN biopsy, LP, PET scan
Management
Hodgkin lymphoma
combination chemotherapy and radiation
increasing role for use of PET scanning to assess early disease response and plan therapy
non-Hodgkin lymphoma
combination chemotherapy
no added benefit of radiation in paediatric protocols
Prognosis
Hodgkin lymphoma: >90% 5 yr survival
non-Hodgkin lymphoma: 75-90% 5 yr survival
Wilms’ Tumour (Nephroblastoma)
Epidemiology
usually diagnosed between 2-5 yr; M=F
most common primary renal neoplasm of childhood
5-10% of cases both kidneys are affected (simultaneously or in sequence)
Asymptomatic abdominal mass (in 80% of children at presentation)
Abdominal pain or hematuria (25%)
Urinary tract infection and varicocele (less common)
Hypertension, gross hematuria, and fever (5-30%)
Hypotension, anemia, and fever (from hemorrhage into the tumor; uncommon)
Respiratory symptoms related to lung metastases (in patients with advanced disease; rare)may have pulmonary metastases at time of diagnosis (respiratory symptoms)
