Oncology

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Chapter 14 Oncology

Long Case

Oncology

The oncology long case provides an opportunity for a general paediatrician to display competence in assessing and managing a child with cancer, and his or her family, both within multiple contexts: the domestic situation, schooling requirements, wider social relationships and within the medical framework. The medical needs reflect the multi-layered levels of care required for the patient and delivered by the general practitioner, the general paediatrician, the paediatric oncologist and other consultants whose help may be required from time to time.

The general paediatrician (the candidate) should be able to demonstrate that he or she can competently handle the medical aspects of a child with cancer as well as the complex professional interrelationships that are involved in coordinating care. The candidate should also be familiar with any recent advances that could affect the management of the patient, which requires a close relationship with the treating oncologist.

The last few years have seen many advances in most areas of paediatric oncology, including a more detailed understanding of the genetic basis of cancer, the development of disease specific investigations and an expansion of disease classifications. For example, acute myeloid leukaemia (AML) is now regarded as a group of related but biologically distinct diseases. This has led to specific treatments being developed for specific subtypes of AML. Advances in paediatric oncology have led to the recognition that prognosis and relapse risk for patients can be better defined by use of multiple molecular biology techniques, such as the use of very sensitive methods to detect cancer-specific genetic changes, which are used to detect minimal residual disease (MRD) burden after therapy. In addition, advances have led to a better understanding of the interacting abnormal genetic and mechanisms that are responsible at a molecular level for the pathogenesis of neoplasms.

Haematopoietic stem cell transplantation (HSCT) now has an expanded set of indications for malignant diseases, including various subgroups of patients with acute lymphoblastic leukaemia (ALL), AML and myelodysplasia.

Of great importance is the role of medical practitioners to provide long-term sensitive surveillance and follow-up. A web-based comprehensive set of guidelines for management of such survivors, the Children’s Oncology Group (COG) Long-term Follow-up Guidelines for Survivors of Childhood, Adolescent, and Young Adult Cancers, can be found at www.survivorshipguidelines.org. Both these initiatives have expanded the literature significantly and are very useful to many candidates.

In Australia and New Zealand, all major paediatric centres are members of the US-based Children’s Oncology Group (COG), a consortium of childhood cancer centres that promotes clinical and laboratory research trials in paediatric oncology.

The general principles of care are similar for patients with haematological malignancies, solid tumours or brain tumours.

An approach to any oncology long case could potentially fit into the following scheme.

History: an overview

At the outset of the interview, it is important to identify clearly the primary and secondary diagnoses, as well as important historical landmarks such as the date of diagnosis, the date of completion of therapy, the history of relapse, or major secondary events such as significant sequelae of therapy (e.g. endocrinopathies or second tumours). Spend your time wisely and carefully in the interview. Limit yourself to about 1–3 minutes to synthesise an overview of the child’s condition and focus on gathering data relevant to the presentation. Parents of oncology patients have frequently had sustained and prolonged medical contact, and could fill hours recounting ‘what the doctor said’. This approach is very time-consuming and often unhelpful.

Before diagnosis

Factors 3 and 4 (above) will impact on the family’s approach to their sick child and possibly bias the relationships that they establish subsequently with people entrusted with the care of their children, particularly as the care and follow-up of a child with cancer nowadays can be expected to span in excess of 10 years for long-term survivors (over 70% of cases) whom we expect will survive.

Management plan

The following is an outline of the major issues that the general paediatrician may need to address, divided into general and specific problem areas.

Growth and development

Irradiation is the single most important factor in determining long-term growth and development. The candidate should know which structures were within the treatment portal, and the total dose used. Patients treated with craniospinal irradiation will be at the combined risk of hypopituitarism and relative shortening of the vertebral column. In addition, even if the pituitary is spared, the thyroid gland may well receive sufficient radiotherapy to result in biochemical hypothyroidism that requires intervention (because if it is untreated, the risk of thyroid cancer is enhanced). Any irradiated area may demonstrate relative soft-tissue atrophy.

In the past, cranial radiotherapy was used for CNS prophylaxis in a majority of patients with ALL. Modern treatment regimens now restrict the use of cranial radiation to 10% or less of patients with ALL. Up to 50% of children treated for acute leukaemia with cranial radiotherapy can have decreased growth hormone secretion. Loss of final height can also be influenced by early (rarely precocious) onset of puberty, or (too) early institution of testosterone therapy for hypogonadism in boys. The management usually comprises growth hormone, delaying treatment with testosterone. There have been reports in the literature linking use of growth hormone with subsequent brain tumour development. However, most investigators do not believe currently that the risk is enhanced.

If there has been a bone marrow transplant, the eyes should be checked by a paediatric ophthalmologist regularly (say, 12–24 monthly) for cataracts from total body irradiation (or from steroids). Hearing may be impaired by drugs such as cisplatin or aminoglycosides, and requires regular review and audiological assessment. Ideally, a formal psychological assessment should be carried out before any cranial irradiation. After treatment, psychological assessment may be repeated on a regular basis, in conjunction with neurological examination, MRI scanning and assessment of school performance, to monitor neuropsychological outcome and provide early rehabilitative intervention if needed. The spectrum of central nervous system damage varies from decreased performance at school, to frank leukoencephalopathy, spasticity and significant intellectual impairment. Intravenous methotrexate may result in leuko-encephalopathy in children with ALL, especially after irradiation. Pubertal development may be early (rarely precocious); however, delayed puberty is more common, with high gonadotropin levels from end-organ gonadal damage.

The one issue to address in adolescent patients is future reproductive potential. In boys with tumours such as Hodgkin’s disease, sperm storage should be considered before irradiation and chemotherapy. In girls, ovarian tissue storage is now available.

Infection

The child on chemotherapy

Common childhood infections occur in children receiving therapy for cancer just as in normal children, and many can be managed in the usual way, provided that the child does not appear toxic, there is an identifiable localised infection, the neutrophil count is greater than 1.0 × 109/L and regular follow-up is provided. Often chemotherapy may be continued, after consultation, through the course of mild infections, be they bacterial or viral. If a child is unwell at home, with a fever and rhinorrhoea, the parents should be advised to contact the paediatrician. If the temperature is above a previously agreed level (e.g. 38°C), then the child should be seen either in hospital.

All children on therapy who are febrile need prompt assessment, and in most cases antibiotics should be started early (without waiting for result of blood count). Blood cultures should be collected before antibiotics.

If the neutrophil count is low (below 0.5 × 109/L), the child should be admitted to hospital. The management of febrile neutropenia should include broad-spectrum parenteral antibiotic therapy (e.g. ceftriaxone, tobramycin, teicoplanin). Antibiotics ideally should be commenced within 1–2 hours of the child reaching the emergency room. It is inappropriate to wait for the results of the blood count before starting therapy with antibiotics, especially if there is any delay in processing the sample in the laboratory. In such circumstances, antibiotics should be started. If the count is normal, there is less cause for concern. Remember, however, that many patients have central venous access devices in place, which can be the cause of serious infections despite normal neutrophil numbers. Always