Introduction

Embryonal tumours are brain tumours that arise from cells that are present in developing embryos. As they are part of a developing baby, this type of cancer is mostly seen in children of younger ages. The survival rate of embryonal tumours depends on the type of tumour, time of diagnosis, and spread of the tumour. While some tumours have high survival rates, neuroblastoma, stemming from the central nervous system (CNS), is particularly challenging due to its propensity for spreading and consequently has one of the lowest survival rates among cancers.

Types of embryonal tumours

1. Medulloblastoma

Medulloblastoma occurs in the central nervous system (CNS), and therefore, it originates from the spinal cord or brain. They are a group 4 type of cancer, indicating that they are highly cancerous and spread rapidly. It commonly forms in the cerebellum with leftover fetal cells, making it easy to identify using an MRI alongside a biopsy. 

2. Neuroblastoma

Neuroblastoma develops from neuroblasts and usually occurs in the sympathetic nervous system or adrenal glands. About 100 children in the UK are diagnosed with this condition. Neuroblastoma necessitates a urine test, along with biopsy and imaging, for diagnosis and monitoring. Elevated vanillylmandelic acid (VMA) and homovanillic acid (HVA) levels in urine are indicative of neuroblastoma due to their association with increased catecholamine production by tumour cells.

3. Wilms tumor

Wilms tumor is kidney cancer that develops from nephroblasts. It is the most common kidney cancer in children in the UK. It is usually unilateral (affects one kidney) but there are cases where it affects both, hence the different course of treatment.

4. Retinoblastoma

Retinoblastoma is a tumour formed by developing retinal cells and is malignant. It usually occurs in children below the age of 5. This condition can either be unilateral or bilateral, depending on the spread of the tumour. The condition is usually diagnosed by an examination of the inside, and back surface of the eye alongside biopsy and genetic testing for the RB1 gene.

5. Rhabdomyosarcoma

Rhabdomyosarcoma is a type of cancer that grows within muscles that are attached to the bone (voluntary muscles). It most commonly occurs in the head-neck area or the genital organs. Kids carrying genes for other inherited diseases like Li-Fraumeni syndrome are more prone to developing this type of sarcoma.

Causes and risk factors

Genetic factors

Cancer is the uncontrolled growth of cells, and since genes control the growth and development of a cell, genetic factors have a large influence on the development of an embryonal tumour. Kids whose parents are predisposed to cancer can pass along the gene, making them inevitably prone to cancer. 

Environmental factors

Since genes are considered the baseline for causing cancer, it is important to note that environmental factors like radiation exposure can cause the development of cancer. The sun’s rays contain UV radiation, which, in large doses, can cause mutations within cells, leading to uncontrolled growth. Subsequently, tobacco smoke and pollution have also been discovered to be carcinogens (cancer-causing molecules), making them a dangerous factor.

Symptoms and diagnosis

General symptoms

• Fatigue
• Random lump
• Persistent cough and breathing problems
• Blood in stool/cough
• Sudden weight loss or gain
• Changes in skin conditions

Diagnostic methods

Imaging tests

Imaging involves tests like MRI (Magnetic resonance imaging), CT (Computed tomography), and ultrasounds, which help get a better image of the tumour itself.

Getting an MRI involves using magnetic fields and dyes to locate any abnormalities in the suspected region. Although these dyes do cause some side effects, like dizziness and nausea, they are quite short-term. During the procedure, which lasts 15-90 minutes, you will move through cylindrical equipment on a motorised bed to get a full body scan.

A CT scan uses X-rays and technology to build up a detailed picture of your internal structures. This method also uses a dye (contrast medium) to highlight the important parts of the scan. This procedure can last from an hour to longer, depending on how the images form and which part of the body is being analysed.

Ultrasounds are useful for diagnosing tumours that cannot be identified through X-ray imaging. It is a quick, simple, and spontaneous procedure. It is also used alongside a biopsy to get the tissue sample from the right region to analyse.

Biopsy

Biopsy uses thin samples of tissue extracted from the patient’s body. It is studied under a microscope to identify the presence of cancerous cells and how aggressive they are. This helps formulate a course of treatment to prevent its spread as much as possible and combat the cancer.

Genetic testing

Genetic testing is a useful tool in figuring out if a cell has mutations, which can then be studied to know if it cause the cell to develop into cancerous cells. These are usually conducted by using blood or saliva samples and provide results within a few weeks, making them useful in identifying cancer risks as well.

Treatment options

Surgery

This involves using surgical techniques to remove the tumour from its origin. It is done when the cancer is still in the early stages and not as malignant. Typically, children who undergo surgeries are administered other treatments to prevent cancer from coming back later in life.

Chemotherapy

Chemotherapy is the use of drugs to kill cancer cells. For embryonal brain tumours, cytotoxic drugs are used to prevent any chances of the cancer spreading. When administering this treatment to children, it is important to remove and store stem cells, which can be introduced back by blood transfusion, to allow them to grow and develop without any complications. Since high doses of chemotherapy will damage and kill cells, this is important. 

Radiation therapy

Radiation therapy involves high-energy beams (mostly X-rays) directed at cancer cells. It is usually administered during the early stages of cancer alongside other treatments like chemotherapy to kill all cancer cells before it spread uncontrollably. This form of treatment can either be external or invasive in the form of injecting radiotherapy implants or consuming radiotherapy capsules.

Targeted therapy

Targeted therapy is the form of controlling proteins that control cancer cell growth and divisions. These therapies are usually small-molecule drugs or monoclonal antibodies which use the cell’s own mechanism to destroy it. As long as the cancer cells do not develop resistance, this therapy can be used as a course of treatment.

Stem cell transplant

Stem cell transplants do not directly attack cancer cells; instead, they provide an avenue from which patients can regrow cells post chemo and radiation therapy. It is a restorative procedure that is essential to providing a normal life post-treatment. These stem cells can either be obtained from the patient or someone else, but treatment is carried out to ensure low chances of rejection.

Support and resources

Support groups for patients and families

There has been an increase in support groups for patients and families to help them cope with the mental burden of embryonal tumours. Being diagnosed with cancer and undergoing strenuous treatments can take a big toll on one’s mental health; therefore, interacting with others going through the same process helps relieve their pain. Even in the case of parents, it is important to gauge support from others to prevent mental breakdowns and stay strong for their child.

Research organizations and foundations

Due to the increasing cases of cancer in children, many organisations have been researching embryonal tumours as well as novel technologies to combat their effects. Organisations like Cancer Research UK and Children’s Cancer and Leukemia Group have plenty of resources to guide families through this painful process.

These organisations also help families raise money for treatments. Cancer treatments involve the use of technologies and equipment, making them quite expensive. Therefore, by joining such organisations, families get financial and emotional support.

Prevention and outlook

Strategies for prevention and early detection

By having regular pediatric checkups and genetic testing, parents could prevent the development of cancer into an incurable disease. It is imperative to pay attention to all the symptoms and unusual signs, as they might be an indicator of cancer. This is extremely important for catching the disease early and preventing it from having too many effects on the child’s body.

Ongoing research and advancements

Constantly, there is funding going into cancer, as it is difficult to pinpoint the cause of it. Especially in terms of embryonal cancer, as it affects children, there need to be opportunities to provide pain-free treatments that do not have life-lasting consequences.

Summary

• Embryonal tumours are formed from foetal cells that are left behind post-development
• There are 5 main types of embryonal tumours
• They can be diagnosed using many methods, like imaging and biopsies
• With lower-grade cancers, it is easier to formulate a course of treatment with drugs, radiation, or surgery
• Many research groups are trying to evaluate how embryonal tumours can be prevented