malignant disease in children

not common
1. 1 child in 500 develops Ca by 15 years old
2. 120-140 new cases per 10^6 kids under 15 years in Western countries
types of disease seen
1. 1. leukaemia
  1. commonest
  2. affects kids of all ages (but there's an early childhood peak)
2. 2. brain & spinal tumours
3. 3. neuroblastoma
  1. almost always seen in 1st 6 years of life
4. 4. soft tissue sarcomas
5. 5. Wilms tumour
  1. almost always seen in 1st 6 years of life
6. 6. (Hodkin lymphoma &) bone tumours
  1. peak incidence in teen & early adult life
7. 7. retinoblastoma
still commonest disease causing death in childhood beyond neonatal period
5 year survival of kids w/ all forms of Ca
1. about 75%
  1. but long term medical & psychosocial difficulties
aetiology
1. precise aetiology is unclear in most cases
  1. likely to involve interaction btw env factors & host genetic susceptibility
2. few established env risk factors
3. in most cases a specific mutation isn't known
  1. even though Ca occurs due to sporadic but possibly heritable mutations in cellular growth & controlling genes
4. bilat retinoblastoma
  1. e.g. of inherited Ca
  2. assoc w/ mutation within RB gene on chromosome 13
5. lots of syndromes assoc w/ increased risk of Ca in childhood
  1. assoc btw Down syn & leukaemia
  2. neurofibromatosis & glioma
clinical presentation
1. localised mass
2. conseqs of disseminated disease
  1. bone marrow infiltration
    1. causing systemic ill health
3. conseqs of Pa from a mass on local strucs or tissues
  1. e.g. airway obstruction 2ndary to enlarged lymph nodes in the mediastinum
Ix
1. radiology
  1. combo of US, plain X ray, CT & MRI
    1. to locate solid tumours & ID & localise evidence of mets
  2. nuclear medicine
    1. e.g. radiolabelled technetium bone scan
      1. ID bone or bone marrow disease
    2. using special markers (MIBG)
      1. localise tumours of neural crest origin e.g. neuroblastoma
2. tumour marker studies
  1. increased urinary catecholamine excretion (e.g. vanillylmandelic acid)
    1. useful to confirm diag of neuroblastoma
  2. high alpha-fetoprotein
    1. often seen in germ cell tumours & liver tumours
    2. levels used to monitor Rx & response
3. pathology
  1. all diags need histological confirmation
    1. bone marrow aspiration
      1. for leukaemia
    2. biopsy
      1. for most solid tumours
        but not always possible for brain tumours
    3. immunohistochemistry
      1. to differentiate tumour types
  2. molecular & genetic techniques
    1. used to confirm diag
      1. e.g. translocation of chromosomes 11 & 22 in Ewing sarcoma
    2. used to predict diagnosis
      1. e.g. amplification of N-myc oncogene assoc w/ poor prognosis in neuroblastoma
4. Mx
  1. detailed ix to define extent of disease (staging) vital to Rx
  2. kids treated as part of collaborative studies that are consistent in care & have helped improve outcomes
  3. initial ix & Rx in specialist centres
    1. w/ MDTs to give intensive medical & psychosocial support needed
    2. subsequent mx shared btw specialist centre, referral hospital & local services in community
  4. teens & young adults
    1. have poorer survival outcomes than kids
      1. related to specific types & biological behaviour of their tumours
    2. are their own distinct population
      1. related to the particular social/psychological needs
      2. -> development of age-approp Rx protocols, facilities & support networks
Rx
1. chemotherapy
  1. uses
    1. as primary curative Rx e.g. in acute lymphoblastic leukaemia
    2. to control primary or metastatic disease before local Rx w/ surgery &/or radiotherapy e.g. sarcoma or neuroblastoma
    3. as adjuvant Rx to deal w/ residual disease & get rid of presumed micromets e.g. after initial local surgery in Wilms tumour
2. radiotherapy
  1. still has role in Rx of some tumours
  2. risk of damage to growth & function greater in kid than adult
    1. need adeq protection of normal tissues & careful positioning & mobilisation of pt during Rx
      1. can be hard in practice
3. surgery
  1. initial surgery often restricted to biopsy to get diag
    1. more extensive ops usually done to remove residual tumour after chemo &/or radiotherapy
  2. high-dose therapy w/ bone marrow rescue
    1. limitation of chemo & radiotherapy is risk of irreversible damage to normal tissues, esp bone marrow
      1. bone marrow stem cell transplantation can be used to intensify Rx of pts w/ admin of potentially lethal doses of chemo &/or radiation
        source of marrow stem cells
        allogeneic
        from a compatible donor
        used in mx of high risk or relapsed leukaemia
        autologous
        from pt himself, harvested beforehand, while marrow uninvolved or in remission
        Rx of solid tumours w/ poor prognosis using conventional chemo e.g. advanced neuroblastoma
supportive care & (short- term) S/Es of Rx
1. bone marrow suppression
  1. anaemia
    1. may need blood transfusions
  2. thrombocytopenia & bleeding
    1. blood product support needed
      1. esp for kids
        w/ leukaemia
        undergoing intensive therapy needing bone marrow transplantation
        under Rx with more intensive solid tumour protocols
  3. neutropenia
    1. -> infection
2. immunosuppression
  1. infection
    1. due to Rx & underlying disease kids w/ Ca are immunocompromised & @ risk of serious infection
    2. kids w/ fever & neutropenia
      1. admit promptly to hospital for cultures & broad spec Abx
    3. opportunistic infections assoc w/ Ca
      1. Pneumocystis jiroveci (carinii) pneumonia
        esp in kids w/ leukaemia
      2. disseminated fungal infection
        aspergillosis
        candidiasis
      3. coag -ve staph infections of central venous catheters
    4. viral
      1. most no worse than in kids w/o Ca
      2. attn to measles & chicken pox
        atypical presentation & life-threatening
        if non-immune, immunocomp kids @ risk from contact w/ these viruses
        give Ig or zoster immune globulin promptly for some protection
        Rx
        aciclovir for established varicella infection
        none available for measles
        use of live vaccines
        contraindicated during chemo & from 6 months-1 year afterward
        after this re-immunisation against common childhood infections recommended
3. GI mucosal damage, nausea & vomiting, anorexia
  1. ->undernutrition
  2. gut mucosal damage from chemo ->
    1. diarrhoea
    2. G-ve infection
  3. mouth ulcers
    1. oommon
    2. painful
    3. if severe, can stop child eating enough
  4. many chemo agents nauseating & induce vomiting
    1. partially prevented by routine use of antiemetic
4. drug-specific S/Es
  1. doxorubicin
    1. cardiotoxicity
  2. cyclophosphamide
    1. haemorrhagic cystitis
  3. vincristine
    1. neuropathy
  4. extent of S/Es not always predictable
    1. monitoring needed during & sometimes after Rx done
5. other supportive care issues
  1. venous access
    1. central venous catheters
      1. avoid discomfort of multiple venepunctures
      2. risk of infection
  2. fertility preservation
    1. risk of infertility due to Ca Rx in some pts
    2. surgical removal of testis or ovary out of radiotherapy field
    3. sperm banking
      1. boys need to mature enough to achieve this
    4. preservation of ovarian cortical tissue
      1. uncertain long term efficiency
  3. psychosocial support
    1. counselling
    2. practical support
      1. transport
      2. finances
      3. accommodation
      4. care of siblings
    3. give detailed written material to parents
    4. encourage return to normal life once Rx established
      1. early return to school
    5. severe stress-> marital probs & behavioural difficulties in child & siblings

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malignant disease in children

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	Created by v.djabatey almost 11 years ago