Dr Ren Manias, Consultant Paediatric Oncologist at Southampton General Hospital, explains what happens and why when doctors find it difficult to diagnose a child’s cancer.
When a child develops cancer, it’s important to make an accurate diagnosis so the right treatment can be planned, and to help families understand what to expect from the journey they’re about to
undertake. In most cases, the history and examination findings, imaging, blood tests and biopsy results fit together to give a clear diagnosis.
However, even straightforward cases can take a few weeks to diagnose and stage accurately, and sometimes diagnosing a child’s cancer can be even more difficult, perhaps because the cancer itself is rare, or because some features don’t fit the usual pattern we expect to see in certain cancer types. In these cases, making a definitive diagnosis can take time. This can be very stressful for parents and can raise all sorts of questions about treatment and what to expect in the future.
Children’s cancer diagnosis has become increasingly sophisticated in recent years. In the past, cancer was simply diagnosed based on imaging, blood tests and histopathology (viewing the tissue down a microscope). But now, other elements are incorporated to further refine the diagnosis and assign specific treatments according to cancer sub-type. These include:
- molecular diagnostics (which analyses the genetic code found inour cells to identify disease)
- cytogenetics (the testing of tissue or blood samples to look for changes in chromosomes that may be a sign of a genetic disease or a type of cancer)
- immunophenotyping (using antibodies to identify cells based on the types of antigens or markers on the surface of the cells to help diagnose certain diseases)
Some types of cancer are diagnosed and sub-classified following central review, which means that biopsies and imaging are sent to national laboratories and panels for expert analysis. This has advantages: treatment can be much more personalised, risk-stratified and targeted, translating to improved survival outcomes with fewer long-term side effects. But it also means it takes longer to gather all the information to form a definitive integrated diagnosis. Sometimes the original diagnosis and treatment plan can even change when all the new information is available.
What happens when a diagnosis takes time?
Your child’s consultant oncologist and treatment team will weigh up the benefits and disadvantages of starting treatment based on the most likely diagnosis, while waiting for all the results to come back. This decision will be based on a number of factors. These include:
- how unwell your child is
- whether the cancer is causing problems such as breathing difficulties or compression of vital organs
- how quickly it seems to be growing
- how confident they are that they’re right about the type of cancer it’s expected to be
In these cases, doctors start ‘empirical treatment’, based on broad principles about how different cancers tend to respond. The idea is that a broad type of treatment can be given to shrink the tumour (or slow its growth), helping the child to feel better. Then, when the diagnosis is confirmed, this treatment can be refined accordingly, and a definitive specific protocol can be decided.
Diagnosing and treating rare cancers
Sometimes, diagnosis is difficult because a cancer is very rare. Rare cancers are treated with the same treatments used for other childhood cancers, including surgery, radiotherapy and chemotherapy, or these in combination. There are now groups of experts in rare childhood cancers who meet to discuss difficult cases and provide guidance on treatment. Doctors also communicate
with colleagues in other countries to develop new forms of treatment and promote research in rare cancers.
National and international collaboration has resulted in significant improvements in care in recent years. However, specific treatment protocols or clinical research trials may not be available for a child’s particular tumour due to the small number of children with rare cancers. In this case, oncologists will offer the most appropriate treatment using guidelines agreed by experts, such as CCLG.
Every diagnosis of cancer is different, and it can be especially hard when there’s a long journey to reach a diagnosis. Your child’s health team will do their best to answer your questions and support
you while they determine the best treatment.
From Contact magazine issue 98 - Spring 2023
