More and more children are surviving cancer due to fantastic improvements in cancer treatments. However, many treatments still cause problems because they can harm healthy body cells as well as cancer cells. These effects can last for many years after treatment, or even become life-long health issues. Doctors call these the late effects of childhood cancer.
There are a lot of different late effects, depending on what treatment was used and where in the body it was directed. Some treatments, like chemotherapy, can affect the entire body and cause various issues. Treatments like radiotherapy, which uses focused radiation to kill cancer cells, are normally directed to just one area of the body.
This can mean fewer effects elsewhere in the body but can unfortunately cause a lot of damage to nearby healthy tissue that also gets irradiated. Radiotherapy is used to treat lots of cancer types, either to shrink tumours before chemotherapy or to kill cancer cells to stop them coming back after treatment.
One place where radiotherapy is used is for cancers in the abdomen, such as for a childhood kidney cancer called Wilms tumour. However, radiotherapy to this area can cause serious damage to an important organ: the spleen.
The organs in the abdomen are close together, so radiotherapy to one area can easily affect nearby organs like the spleen.
Google says that there are around 79 organs in the human body – but the spleen probably wouldn’t make it into anyone’s top ten organs. However, it turns out it’s quite important.
It’s a small organ that lives in the left side of your body, tucked under your ribs and next to your stomach. It mostly deals with blood: removing old blood cells and making sure there are the right amounts of the different types of blood cells. As part of this, it also fights any germs that end up in the blood using immune cells. All in all, it helps to keep your blood, and therefore you, healthy.
What about when it goes wrong?
When the spleen is damaged, it can start to get rid of blood cells which are healthy. This can lead to things like anaemia, issues with blood clotting properly, and an increased risk of infections. This is why it is important to find out how radiotherapy affects the spleen.
Dr Paula Adkin
Dr Paula Adkin is a children and young people’s doctor who specialises in long-term follow up after cancer, as well as a late effects researcher. Since 2021, she has been working on a CCLG-funded project led by Dr Henry Mandeville, which aims to find out whether radiotherapy near the spleen could put patients at a higher risk of serious infections later in life.
She said: "Radiotherapy is an important component of treatment for many children and teenagers with cancer, however, the long-term side effects of receiving radiotherapy to the spleen are poorly understood.
Over the past few decades, we have seen a significant improvement in survival rates for children diagnosed with cancer. Treatments are improving, however 60-70% of long-term survivors are left with at least one significant side effect (late effect) of treatment. The goal should now not just be survival, but to live well after cancer treatment.
In the project, the team has worked with research groups in Birmingham and France and have reviewed nearly 9,000 cases of childhood cancer patients. They looked at how many times these survivors had had serious infections, for example, needing hospitalisation, and compared these rates in different treatment groups.
Paula hopes that they will find out precisely what effect the radiotherapy has on their risk of severe infections, and what factors, such as dose or proportion of the spleen that received radiation, affect this risk.
Paula said: "We know that patients who have their spleen removed are at an increased risk of infection. However, there have been very few studies exploring the risk of infection following radiotherapy to the spleen. Radiotherapy may affect the spleen’s ability to neutralise certain bacterial infections. Currently, patients receiving high dose abdominal radiotherapy are advised to take life-long antibiotics, as well as receive 5-yearly vaccinations to reduce this risk.
"We are exploring whether the radiotherapy dose or the volume of the spleen receiving radiotherapy has the biggest influence on risk of infection."
Paula with Dr Henry Mandeville and co-investigator Dr Mary Taj.
What's next?
Now that the researchers have reviewed the huge amount of data available, they are ready to analyse it. This is quite a long and complicated process, but there are already intriguing results.
Explaining that their analysis was ongoing, Paula added:
It appears that the volume of the spleen in the radiotherapy field may be more significant than the average dose. More data is required to determine how radiotherapy affects the function of the spleen, and to find out which survivors may benefit from life-long antibiotics.
Once the analysis is complete, Henry and Paula will be publishing their findings so that other doctors and researchers can benefit from their work. They also hope to get funding to answer their remaining questions.
Ellie Ellicott is CCLG’s Research Communication Executive.
She is using her lifelong fascination with science to share the world of childhood cancer research with CCLG’s fantastic supporters. You can find Ellie on X: @EllieW_CCLG
