COMMON CHILDHOOD CANCERS. PL Tan and TC Quah

Transcription

1 COMMON CHILDHOOD CANCERS PL Tan and TC Quah In Singapore, approximately 1 in 600 children between ages 1 and 15 develops cancer and there are about 83 new cases a year of childhood cancer nationally. As in most developed countries, the mortality rate is approximately 30% (about 25 deaths annually for Singapore), making childhood cancer the commonest cause of death in children locally. Besides the local cases, we manage a significant number of childhood cancers from the region as well. CONTENTS Introduction Common Childhood Cancers o Types of Cancers o Presentation Patterns Making the Diagnosis Briefly, on Management Follow-Up Care References 1

2 1. COMMON CHILDHOOD CANCERS Types of Cancers Childhood Cancers in Singapore Leukaemia 32% 30% Brain Tumours Lymphomas Neuroblastomas 8% 10% 20% Bone and Soft Tissue Sarcomas and Others Childhood Leukaemias Leukaemias comprise 30% of these cancers. The most common are the acute lymphoblastic leukaemias (ALL), which make up 80% of all leukaemias. The peak age of presentation is between 2 to 3 years of age. The second commonest are the acute myeloid leukaemias (AML) (about 15%). Chronic myeloid leukaemias (CML) which make up < 5% of the cases are occasionally seen. Childhood Brain Tumours Brain tumours comprise about 20% of childhood cancers and are the second most common cancer in children. The common brain tumours include gliomas of varying grades of aggressiveness, medulloblastomas and craniopharyngiomas. Children of all ages are affected equally. Lymphomas Non-Hodgkin s lymphoma (NHL) and Hodgkin s disease (HD) make up the lymphoma group. Generally, older children who are above 10 years are affected. NHL accounting for 6% of all cancers is commoner than HD which contributes 4%. 2

3 Neuroblastomas and other infant tumours Neuroblastomas (NB) are the next largest group and about 6 to 7 new cases (8%) are diagnosed each year. Half of these patients are younger than 2 years and 30% younger than 1. Together with retinoblastomas, Wilms tumours (also known as nephroblastomas) and hepatoblastomas, these tumours occur primarily in the infants and pre-schoolers age group (<5 years). Others Bone tumours (osteosarcomas, Ewing s sarcoma), soft tissue sarcomas (rhabdomyosarcomas, non-rhabdomyosarcomas soft tissue sarcomas), germ cell tumours and other rarer carcinomas comprise the rest. 2. PRESENTATION PATTERNS Diagnosis usually does not pose a problem when symptoms and signs are obvious and when disease is advanced. Commonly these include: Pallor Bruising and petechiae Lymphadenopathies (generalised or single, persistent and growing) Hepatosplenomegaly Masses in the abdomen Limb swellings (hard and rapidly growing masses in the long bones) Visual disturbances (knocking into things) Symptoms and signs of raised intracranial pressure or endocrine disturbances Constitutional symptoms are usually present with: Non-specific changes in behaviour Lethargy Loss of appetite and weight Prolonged, intermittent fevers that resolve for short periods of time but recur, with little evidence of a source of infection (e.g. URTI), indicative of a malignant fever. 3

4 The Masqueraders Bone pain or aches as primary presenting complaints are not uncommon and are usually non-articular in leukaemia and bone cancers, in contrast to the articular involvement in rheumatologic disorders. Very small children with these pains often present with persistent irritability and a preference for inactivity. Red herring injuries are common and can delay the diagnosis of bone tumours. Other presentation symptoms such as gum swellings and bleeding despite good dental hygiene (infiltration from AML) can be the first symptoms. Histories from the main carers may suggest a white pupil ( cat s eye ) or abdominal masses felt while bathing the children or even an unusually protuberant abdomen. Unusual emergency presentations 1 Superior Mediastinal Syndrome (SMS) Thoracic tumours such as NHL, HD, NB and germ cell tumours can cause compression, obstruction or thrombosis of the superior vena cava with or without tracheal compression causing respiratory embarrassment. Patients often have oedema, cyanosis and plethora of face and neck with cervical and thoracic venous distension. Wheezing or stridors are common and coexisting signs of pleural or pericardial effusion may be present. These signs might be very subtle in the beginning and there were occasions where patients were inappropriately treated for asthmatic exacerbations with steroids resulting in temporary relief. Spinal Cord Compression Acute retention of urine or constipation with refusal to walk due to lower limbs weaknesses are often the presenting features of acute spinal cord compression. Dumb-bell neuroblastomas in the spinal cord and lymphomas are the commonest causes. These signs may be difficult to detect as young children often cannot tell or cooperate for good neurological examination. 4

5 3. TRENDS AND SURVIVAL In the USA, the incidence of all childhood cancers have remained relatively constant from 1975 to 1997 for children younger than 15 years. 2 There was an apparent increase in the incidence of childhood brain tumours in the late 1970s to mid-1980s, but the incidence has not increased since the widespread availability of magnetic resonance imaging in the mid-1980s suggesting that improvements in diagnosis and reporting may have accounted for that apparent increase. 3 In Singapore, the trend has been similar. 4, 5 With risk-adapted, dose-intensified therapies, survival rates have improved dramatically for childhood cancers in general since the 1960s from an overall 5-year survival rate of 28% to rates exceeding 75% in the 1990s for children less than 15 years old MAKING THE DIAGNOSIS Making a diagnosis of childhood cancer can be complex but if attention are given to these areas, the risks of missing or delaying the diagnosis might be reduced significantly. Thorough history and examination 1. Identify the actual main carer 2. Sedation might be needed to examine a fretful child (caution with very young children) 3. Always check the for red reflexes for well baby visits High index of suspicion The eye don t see what the mind don t think Repeated reviews New findings or progression can be detected earlier Do simple investigations (e.g. blood counts, simple X-rays) if in doubt Pay attention to the concerns of highly anxious parents Understand the background for any disagreement with regards to further investigations, as intangibly, parents often intuitively know something is wrong with their child. 7 Consult with a GP or a specialist colleague 5

6 Our Paediatric oncologists here are always happy to provide advice and are just a phone call away. 5. REFERRAL Once a child with a suspected cancer is referred to a Paediatric oncologist here, he or she will be seen within 24 hours. 6. BRIEFLY, ON MANAGEMENT The chief aims in the initial periods include attending to immediate medical problems or emergencies. Upon counselling of parents and the main carers, diagnostic tests including a series of blood tests, radiological tests and biopsies will be arranged. Treatment usually starts within a day or a week after confirmation of the diagnosis. Referrals are made concurrently to medico-social workers and play therapists to assist in parental / patient education and support. Often in the course of the first admission, the options of indwelling central venous catheters are offered to parents/ patients. Having such an access allows safe administration of chemotherapy and easy blood sampling and significantly reduces distress and anxiety for all patients. These catheters are usually inserted under general anaesthesia (GA) when the child is stable or at the same sitting of a biopsy that is done under GA. 7. FOLLOW-UP CARE Generally, the patients stay for 5 days to 3 weeks for the diagnosis admission, depending on presence or absence of complications. Most therapies are outpatient based and follow-ups are once or twice a week and as needed. There will be requirements for inpatient therapies and these vary with different protocols. Patients have 24 hours access to the doctors and nurses in the team and admissions if needed are arranged directly. Patients can choose to see their regular family doctor for common illnesses if they prefer. Detailed letters of the diagnosis and management plans are prepared for this purpose and as standby for emergencies. 6

7 REFERENCES 1. Rheingold SR, Lange BJ. In: Pizzo PA, Poplack DG eds. Principles and Practice of Pediatric Oncology (4 th edition): Oncologic Emergencies pp Surveillance, Epidemiology, and End Results (SEER) program, National Cancer Institute. 3. Smith M, Freidlin B, Ries L, et al. Trends in reported incidence of primary malignant brain tumours in USA [see comments]. J Natl Cancer Inst 1998; 90: Chia KS, Seow A, Lee HP, Shanmugaratnam. Cancer Incidence in Singapore Singapore Cancer Registry Report No Chia KS, Seow A, Lee HP, Shanmugaratnam. Trends in Cancer Incidence in Singapore Singapore Cancer Registry Report No Ries LA. In: Harras A, Edwards BK, Blot WJ, et al., eds. Cancer: rates and risks. Bethesda, MD: National Cancer Institute, 1996: Mary Dixon-Woods, Michelle Findlay, Bridget Young, Helen Cox, David Heney. Parents' accounts of obtaining a diagnosis of childhood cancer. Lancet 2001; 357: