Lymphoid and haematological malignancy and related conditions

Chapter 8 discusses lymphoid and haematological malignancy and related conditions in children and young people. Radiotherapy is less frequently used in haematological malignancy and allied disorders than it once was. In Hodgkin lymphoma, better risk stratification, more effective systemic therapy and the use of 18F-fluoro-deoxyglucose positron emission tomography (18F-FDG-PET) imaging to assess response to chemotherapy have facilitated a safe reduction in the indications for radiotherapy. Nonetheless, radiotherapy remains an important component of multimodality therapy in patients with advanced or poorly responding disease. In acute leukaemia, radiotherapy is no longer used as part of first-line treatment schedules. Instead, it is reserved for refractory and relapsed disease. Total body irradiation remains valuable as part of conditioning prior to haemopoietic stem cell transplantation. Cranial and testicular radiotherapy is helpful for selected patients who relapse in these sanctuary sites. Radiotherapy is also indicated infrequently in some unusual and benign haematological conditions.

Aftercare

Chapter 5 discusses care during and after radiotherapy for children and young people. During and immediately after treatment, children and young people receiving radiotherapy need monitoring for acute complications of treatment and may require supportive care. Following completion of treatment, a response assessment is needed, followed by ongoing surveillance for recurrence. If relapse occurs, consideration can be given to further treatment, which may be radical or palliative in intent. With the passing of time, the risks of relapse recede and monitoring for the late effects of treatment becomes more important. As the majority of patients will have some long-term sequelae, some of which can be ameliorated by timely intervention, patients should be followed in a multidisciplinary clinic. A detailed treatment summary will help predict the risk of complications and guide long-term follow-up. Patients, when they reach adult life, should be aware of possible problems, including fertility issues and second malignant neoplasms.

Diagnosis, risk stratification, and therapeutic choices

Chapter 3 discusses cancer diagnosis, risk stratification, and therapeutic choices in children and young people. Radiological investigations support the diagnosis and provide staging information for accurate risk stratification. Interventional radiology is useful for obtaining tissue for pathological examination. Histopathology and molecular studies define the precise tumour type and subtype and are used to confirm or rule out the presence of metastatic disease. Post-operative histopathology defines the extent of spread and is important for the staging of some tumours. Together, these findings inform multidisciplinary team discussion and help to identify the best treatment schedule. A significant proportion of cancers have a genetic basis, and it is important to identify these from the family history, predisposing syndromes, or tumour type. Modern molecular genomic techniques have made definitive diagnosis easier. Some genetic conditions lead to increased radiosensitivity and may predispose the patient to excessive radiation-related morbidity and a high risk of second primary tumours.

Cancers in children, teenagers, and young adults

Chapter 1 introduces the topic of cancer in children, teenagers, and young adults. Cancer in children and young people is rare: less than 1% of total cancer incidence. There is a wide variety of tumour types, and these are often different from the common adult cancers. Leukaemia, brain tumours, and malignancies of embryonal origin are most common in younger children. Genetic predisposition is important. Environmental causes are less common than in adults. Treatments have improved significantly and, currently, about three out of four children and young people are cured of their cancer. Multimodality protocols including chemotherapy, surgery, and, more frequently now, biological treatment, in addition to selective use of more sophisticated radiotherapy techniques, is the norm. Increasing personalization of treatment based on risk stratification has allowed for improved cure rates with a reduction in treatment-related morbidity.

Central nervous system

Chapter 6 discusses brain tumours, the commonest solid neoplasms of children and young people, which account for about one-quarter of all malignancies in this age group. There are many different varieties: medulloblastomas and other embryonal tumours, and low- and high-grade gliomas, form the commonest categories. Craniopharyngiomas, ependymomas, intracranial germ cell tumours, and other rare types are less frequently encountered. Most brain and spinal tumours are treated with a multimodality schedule comprising surgery, chemotherapy, and radiotherapy. The place of radiotherapy in the management of central nervous system tumours is described in detail.

Radiotherapy preparation and treatment

Chapter 4 discusses radiotherapy preparation and treatment. There are many ways of delivering radiotherapy, and the best technique should be chosen for each child, teenager, or young adult for whom irradiation is indicated. Image-guided, intensity-modulated radiotherapy techniques are gradually replacing three-dimensional conformal approaches. Proton beam radiotherapy offers the advantage of lower normal tissue radiation doses in many circumstances, and its availability and use is growing. Highly specialized techniques including hypofractionated stereotactic radiotherapy, molecular radiotherapy, and brachytherapy offer important advantages in a small number of cases. Anaesthetic teams are essential for the immobilization of infants and most younger children requiring radiotherapy. Play specialists may reduce the need for anaesthesia in some cases, and greatly facilitate treatment of older children. Good imaging is essential for accurate target volume delineation, and careful prospective quality assurance of this process will help to improve outcomes.

Extracranial solid tumours

Chapter 7 discusses paediatric extracranial solid tumours. Paediatric extracranial solid tumours are very diverse. They include soft tissue and bone sarcomas, embryonal tumours such as neuroblastoma and Wilms tumour, and carcinomas. The prognosis of each type varies considerably depending on stage, tumour biology, and other factors. Careful risk stratification is necessary to determine the best approach to treatment. This is often multimodal, usually including chemotherapy and surgery, and sometimes radiotherapy. It is often possible to avoid radiotherapy in the better-prognosis risk groups, reserving this treatment, and the associated late effects, for those with the worst outlook. A strong evidence base has developed for the most common tumour types, but further clinical trials are required to optimize the role of radiotherapy.

Cancer services for children, teenagers, and young adults

Chapter 2 discusses cancer services for children, teenagers, and young adults. Paediatric and teenage and young adult practice covers an age range from babies through adolescence to maturity. Oncological services should be age and developmentally appropriate. As cancers in this age group are rare and different from common adult malignancies, specialist treatment should be limited to regional centres with the required expertise. Multidisciplinary teams with diagnostic, therapeutic, and supportive-care expertise are needed. As decision-making can be challenging, wider discussions are sometimes required to select the best treatment option. The aim is to maximize the chance of cure with the fewest late effects. Radiotherapy for children and young people is complex and requires a team approach including specialist radiographers and radiation oncologists, as well as support from paediatric medical, nursing, and anaesthetic staff. Enrolment into clinical trials is the standard of care. Paediatric radiation oncologists should be involved in these trials.