The difficulty in establishing a definitive diagnosis of neuroblastoma sets the tone for the complex and anxious journey ahead.
Many doctors will never see a case of the disease throughout the course of their career due to its very low incidence. Another complicating factor is that neuroblastoma does not always present with the same symptoms in two individuals, with symptoms often very similar to those of less severe childhood illnesses . A fever, pain in joints or bones, abdominal pain, bruising and weakness are all potential signs. Even once referred to an oncologist, a child must go through rigorous tests to determine the nature of their tumour.
Neuroblastoma is a cancer of the sympathetic nervous system, with tumours more often than not occurring in the adrenal glands or abdomen. Abdominal pain or the recognition of an abdominal often leads to diagnosis. Definitive diagnosis is made a biopsy of a child’s tumour or bone marrow.
The significant heterogeneity (differing characteristics) between patients translates into diverse progress and outcomes in each case. Tragically, in the majority of cases the disease has already spread by the time of diagnosis, meaning many children fall into the high risk category. Metastatic sites (places which tumours have spread to) often include the bones and bone marrow, sometimes the lungs and lymph nodes and less frequently the brain. Neuroblastoma is aggressive and malignant, with half of all neuroblastoma all cases classified as high risk, and necessitating treatment immediately.
Due to the nature of the cancer, therapies for high risk neuroblastoma often come from the more intensive end of the cancer treatment spectrum. This can include chemotherapy, surgery, myeloablative radiation, and stem-cell transplants. Around a fifth of high risk neuroblastoma cases, however, will be resistant to initial therapy (refractory). Some children will therefore never reach remission and many of those who do will subsequently relapse. Relapsed neuroblastoma is the most dangerous form of the disease. The recurrence of the disease is often down to minimal residual disease (MRD) which has resisted chemotherapy and radiatiotherapy.
Despite its severity, neuroblastoma has comparatively high rate of spontaneous regression, meaning some cases go into remission without a need for treatment.
Another important risk factor is the presence of the MYCN oncogene, which is found in around 20% of patients and is strongly associated with a poor prognosis. Along with other factors, the occurrence of this gene is used to classify patients into risk groups, which relate to the expected severity of their condition. These other risk factors include age, tumour pathology, genetics and the stage which the disease has already reached. The heterogeneity of the cancer, and its distinctly different features from adult cancers, make it difficult for doctors to give reliable prognoses.
Despite progress in the treatment and understanding of neuroblastoma, standard therapy is still centre around chemotherapy, radiation, and restorative stem-cell transplant. Survival rates for neuroblastoma have fallen behind the improving outcomes in childhood cancer at large. This is particularly true in high risk cases. Earlier diagnosis, advances in the application of genomic data in therapy, treatment paths individual to patients, and targeted therapies which reduce toxicity are all crucial to improving the lives of children with neuroblastoma. It is essential that promising developments in research are translated as swiftly as possible into effective interventions that not only save lives, but offer the maximum quality of life after cancer.