Cure rates for cancer in childhood have improved substantially in the past 50 years. Today, 80% of children with acute lymphoblastic leukaemia (ALL) survive, similar results occur in non-Hodgkin lymphoma, 90% of children with Wilms’tumor are cured and improvement has occurred in various sarcomas.
But for some survivors, cure comes at a price, best illustrated by the evolution of treatment for ALL where cure did not occur until measures were taken to prevent leukaemic involvement of the central nervous system (CNS). It was subsequently recognised that many survivors exhibited neuro-cognitive problems which required remedial education support. Further studies were then undertaken to determine whether effective CNS prophylaxis could be achieved without long-term toxicity. Another example of serious late adverse effects occurred in South Australia where more patients treated for Hodgkin lymphoma have died from treatment complications than from progressive disease.
All modalities of cancer treatment can cause late adverse effects despite careful monitoring during the acute treatment phase. Thus some surgical procedures can produce long-term functional problems which have resulted in a re-appraisal of certain surgical interventions. Radiation therapy causes abnormalities in soft tissue and bone development, various endocrinopathies, and increases the risk of occurrence second tumors. In the past 20 years, chemotherapy has been progressively intensified and while this has clearly improved survival, it can also cause late organ dysfunction, infertility and secondary leukaemia. The new concept of “risk-adapted therapy” promotes less intensive treatment for those with “low-risk disease” with the aim of minimising late effects without compromising the chance of cure.
Finally, long-term follow-up of childhood cancer survivors is generally considered to be necessary, but how is it best conducted – in primary care settings or in hospital-based late-effects clinics, and should such follow-up be physician or nurse led? Discussion of this topic continues.