Precision Oncology tags
What is the CyberKnife? What is stereotactic radiotherapy?
The CyberKnife is a very sophisticated radiotherapy machine that is used to deliver "stereotactic radiotherapy" robotically. It allows very high doses radiotherapy to be delivered to small tumours safely and effectively. "Stereotactic" refers to accurate co-ordinate referencing to achieve the very high level of anatomical precision and reproducibility of each treatment session.

For stereotactic radiotherapy, the treatment is given in multiple treatment sessions (usually 3, 5 or 8 sessions in total). Stereotactic radiosurgery can also be delivered using the same machine, which is when the dose is given in a single treatment session.

The CyberKnife consists of a compact linear accelerator which generates high energy x-rays fitted to a sophisticated robotic arm. This means that x-rays can be directed very accurately and reliably from a number of different angles. These multiple beams can be directed at a tumour to deliver a very high dose of radiotherapy, whilst giving only low doses of radiotherapy to the normal tissues that surround the target.

Importantly, the CyberKnife can also track the tumour position continuously before and during each treatment session. For example, the robot can continuously adjust the beam direction if the tumour moves with breathing. This means the tumour is always in the beam target and we can confidently deliver the full dose of treatment to the tumour target. This also helps minimise the dose to surrounding normal tissues, therefore reducing side effects of treatment.

Treatment with the CyberKnife

Stereotactic radiotherapy and radiosurgery are suitable for specific clinical situations. At Precision Oncology UK, all treatments we give are double checked and approved by more than one Oncology expert to ensure all patients receive the highest quality of care.

In clinic, the Precision Oncology Consultant will provide a thorough consultation and fully explain the treatment procedure, the benefits and any potential side effects or risks. All cases are discussed with the Multi-disciplinary Team, with whom we work closely to ensure you have easily accessible support during and after your treatment.

If the tumour is likely to move during treatment, then small metal markers, called fiducials, will need to be placed around the target. These can be seen by the CyberKnife system and are used by the robot to track the tumour during treatment. The insertion is a relatively simple procedure that is performed by a Consultant Radiologist. In an out-patient procedure, the Radiologist will insert the markers through the skin in the correct position inside internal organs using scans to define and guide the placement.

Just over a week after the markers have been positioned, a set of scans will be performed. These scans are done with you in the best position for the specific treatment being considered. This will be discussed with you in detail in your first clinic appointment. For example, it may be with you lying on your back with your arms on your chest, or arms by your side, or wearing a tailor-made mask that fits over your head and shoulders if an area in the head and neck is to be treated.

These scans are used to design the treatment, optimising the beam directions and sizes to give the best possible dose to the tumour and the lowest possible dose to the surrounding tissues. This work is done by expert physicists. A computerised 3D map of the doses is created so we know exactly how the treatment will be delivered and where the dose goes.

Once all the calculations are checked, the treatment can begin. In many ways the treatment is similar to having a scan; all the patient needs to do is lie still on a couch in the CyberKnife treatment room. Specialist treatment radiographers will ensure the position is correct, then leave the room to operate the CyberKnife from the control area. They are able to monitor the patient via closed circuit TV. The CyberKnife will then move to planned positions and deliver the treatment. The treatment itself is painless and there is nothing to see or to feel.

Each treatment can last between 45 minutes to two hours. Treatments are usually in a single session, or 3 to 8 sessions given over 3 to 14 days. The whole treatment is given as an outpatient and there is usually no need for admission to hospital. The timings of treatment will be discussed with you in your first clinic appointment with Precision Oncology UK.

The side-effects vary according to where in the body the treatment is being given. All possible side effects will be fully explained before the treatment is agreed.

There is usually a review appointment with the doctor about a month after treatment is complete. A programme of follow up after that will be discussed in clinic, and further scans booked to assess the effect the treatment has had. These are usually done about 3 months after the last CyberKnife session.

In clinic, the Precision Oncology Consultant will provide a thorough consultation and fully explain the treatment procedure, the benefits and any potential side effects or risks. All cases are discussed with the Multi-disciplinary Team, with whom we work closely to ensure you have easily accessible support during and after your treatment.
What is VMAT?
Volumetric Modulated Arc Radiotherapy (VMAT) is the most advanced technique available for giving radiotherapy using a conventional "linear accelerator."

A linear accelerator produces high energy X-rays. These are the same X-rays used for imaging, for example taking a Chest Xray or a CT scan, but have higher energy which means they affect the DNA in cells. Imaging X rays have a low energy and generally pass straight though cells and do not cause significant effects.

In VMAT, the X-ray beam is switched on and the treatment machine rotates around the patient. This means that the treatment is delivered from every direction possible, spreading out the dose entering the patients and therefore reducing the dose to the parts of the body outside the tumour.

At the same time, the intensity of the beam is continuously varied. Portions of the tumour that need a higher dose from a particular direction receive more X-rays during one moment, and as soon as the direction changes as the machine rotates, the X-ray intensity is changed appropriately. Likewise, the intensity is reduced dramatically when the beam passes though important normal tissue, therefore reducing the dose. The combination of the continuous rotation and the varied intensity of the beam across its profile results in a dose of radiotherapy that is high where we want it to be and lower than previously achievable on normal tissues, reducing the risk of side effects.

If VMAT is the most appropriate form of radiotherapy for your condition, we will give you more information about, including possible side effects and useful websites, when we see you in the Precision Oncology UK clinic.

In clinic, the Precision Oncology Consultant will provide a thorough consultation and fully explain the treatment procedure, the benefits and any potential side effects or risks. All cases are discussed with the Multi-disciplinary Team, with whom we work closely to ensure you have easily accessible support during and after your treatment.
Radiotherapy for Oesophageal Cancer
Oesophageal cancer affects the gullet, the tube that connects the throat to the stomach. There are 2 main types of oesophageal cancer - squamous cell carcinoma (SCC) and adenocarcinoma (AC). The diagnosis is determined by taking a sample, usually through an endoscope (a thin flexible tube with a camera, inserted in to the oesophagus). The extent of disease will also be assessed by either CT or PET-CT scan.

When oesophageal cancer is diagnosed at a very early stage, it may be treated with surgery alone. More frequently, the primary tumour extends deeper into the oesophageal wall, or cancer cells have spread to the local lymph nodes. In these situations, additional treatment may be needed.

SCC localized to the oesophagus and local lymph nodes is very sensitive to radiotherapy and therefore the curative treatment approach would be radiotherapy and chemotherapy given at approximately the same time. Treatment is given over 5 to 5.5 weeks. Chemotherapy is commonly given as a combination of 2 infusions and continuous tablets for the duration of the radiotherapy.

If an oesophageal cancer planned for radiotherapy is in the lower oesophagus, near the diaphragm, movement of the tumour with breathing can be significant. At Precision Oncology UK, we therefore use 4-dimensional CT (4D-CT) radiotherapy treatment planning to compensate for any movement during breathing. A 4D-CT scan provides additional information on the range of tumour movement throughout the breathing cycle. With this information we shape an individualised radiotherapy field to the motion of the tumour. This will minimize radiation dose to nearby organs and thereby side-effects to lung, heart, liver, bowel and stomach. All radiotherapy treatments are delivered using Volumetric Arc Radiotherapy (VMAT - see information on this website].

Treatment for AC is often with surgery. However, in many cases we would recommend chemotherapy before and after surgery, or an alternative approach, combining radiotherapy with chemotherapy over 4.5 weeks before surgery. These additional treatments have been proven to increase the chance of cure and a successful operation compared to surgery alone. We may also recommend radiotherapy with chemotherapy as the primary treatment for AC for patients who are not fit or are otherwise unsuitable to undergo an operation.

When you meet us at Precision Oncology UK, we will discuss your individualized oncology treatment plan and will provide additional information on possible side effects. We will also direct you to websites providing useful information.

In clinic, the Precision Oncology Consultant will provide a thorough consultation and fully explain the treatment procedure, the benefits and any potential side effects or risks. All cases are discussed with the Multi-disciplinary Team, with whom we work closely to ensure you have easily accessible support during and after your treatment.
Radiotherapy for rectal cancer
Cancer of the rectum can be treated with an operation called Total Mesorectal Excision. In this Operation, the surgeon removes the tumour, the rectum and a layer of tissue around the rectum called the mesorectum. The success of the operation depends on the surgeon removing the tumour with a good safety margin of mesorectum around it.

Sometimes we can tell from initial scans, particularly MRI scans, that this surgical safety margin is not achievable. Under those circumstances, the multi-disciplinary team, consisting of oncologists, surgeons and radiologists, often recommends radiotherapy with some chemotherapy to shrink the tumour before the operation.

As the tumour shrinks during and after the radiotherapy, the safely margin increases and we can then increase the chance of a successful operation.

A good safety margin dramatically reduces the chance of the disease returning in the same region at some future timepoint.

The technique of radiotherapy we use in Precision Oncology UK for these situations is Volumetric Arc Radiotherapy (VMAT - see information on this website]. This very precise form of radiotherapy allows a very effective dose of radiotherapy to be given to the target, and reduces the dose to nearby organs like the bladder, small bowel and hips. The aim is to minimise side effects from treating normal tissues near the target.

We will give you more information about this treatment, including possible side effects and useful websites, when we see you in the Precision Oncology UK clinic.

In clinic, the Precision Oncology Consultant will provide a thorough consultation and fully explain the treatment procedure, the benefits and any potential side effects or risks. All cases are discussed with the Multi-disciplinary Team, with whom we work closely to ensure you have easily accessible support during and after your treatment.
What is SIRT?
SIRT is "Selective Internal Radiotherapy" or sometimes called "radioembolisation (radioembolization)" (RE). It is a way of treating liver tumours, whether those tumours originate from the liver itself, or have spread to the liver from elsewhere in the body (e.g. the bowel or breast).

Millions of little radioactive "beads" are injected into the artery that supplies the liver. The beads are tiny and too small to be seen without a microscope. Each bead is much smaller than the width of a human hair.

These microspheres contain a radioactive source which emits radiation that travels only a very short distance within the liver. Once injected into the liver, the microspheres emit radiation, which treats the tumour cells near the beads. The beads also help to cut off the blood supply to the tumours, thus starving them of oxygen. The radiation lasts for a period of days, and the treatment effect on the tumour can last much longer.

What should I expect?

This treatment is only suitable for patients who have malignant liver tumours and whose scans have been reviewed at a meeting of cancer specialists, called a Multi-Disciplinary Team Meeting.

To assess your suitability for the microspheres treatment, the following investigations will be performed:

Liver Angiogram

  • A catheter is inserted into your groin and contrast is injected into the blood vessels that supply your liver.
  • Even if you have a similar procedure before, you will need another one. This angiogram specifically assesses the blood flow and maps the blood vessels within your liver.
  • During this procedure, the radiology consultant doing the angiogram will block off ("embolise") any vessels that he/she thinks might represent a risk of microspheres going elsewhere in the body. There is no risk associated with blocking off these tiny vessels, but it can sometimes cause mild pain for a few hours after the procedure, so you will be monitored in the hospital for at least 4 hours before you can go home.
  • On the same day, this procedure will include a Nuclear Medicine scan of your liver to calculate the correct microspheres dose for you.

CT Scan

  • You will need two CT scans, the first one a few weeks before the treatment and another one approximately 2-3 months after the procedure
  • CT scans you have had recently may be sufficient for measuring the liver tumour.
Based on the results of these 2 tests, it will be decided whether you can have the SIRT treatment and the dose will be ordered from abroad so that it is ready for the day of your treatment.

Injection of the Microspheres

  • Approximately one week after the liver angiogram, you will have a very similar procedure, during which the Microspheres will be injected into the liver via a catheter.
  • You will be monitored in the hospital for at least 4 hours after the procedure and you may be asked to stay in hospital overnight for observation in case you need strong painkillers.

After the treatment

  • After the first liver angiogram and after the procedure, you may be admitted for 1 night on each occasion.
  • It is important to drink plenty of fluids for 6-8 weeks after this procedure.
  • The range of the radiation given off inside the body is only 1-2 centimetres. Very little of the radiation will leave your body, but as a safety measure you will be given a yellow card telling you some precautions you must take when you leave hospital.
  • You may have visitors but they should be over 18 and no one who is pregnant may visit.

Side effects

As with many treatments, you may experience side effects from the procedure, but not all patients will get them.

The most common side effects are:

  • Fatigue - this is the commonest side effect. It is usually mild, but it can last for 4-6 weeks.
  • Mild fever - can last from a few days to a week and usually does not cause concern.
  • Abdominal pain for a few hours after the procedure and sometimes several days. This will be controlled with painkiller tablets.
  • Nausea, usually mild and easily controlled with tablets.
  • Diarrhoea, usually mild and not requiring treatment.

If you do experience any side effects, they will be treated with medications during your stay and you will be given tablets to take at home.

Side Effects (less than 1 in 10 patients treated)

  • If a few microspheres reach the stomach or intestine, they may cause symptoms of indigestion, gastritis or abdominal discomfort similar to having a peptic ulcer. To prevent this from happening, you will be asked to take an anti-ulcer treatment once daily from the day you have the liver angiogram for a minimum of 8 weeks.

Rare Side Effects (less than 1 in 100 patients treated)

  • Lung - if a few of the microspheres reach the lungs, you may experience some shortness of breath and a cough for 2-3 months after the treatment. This is very rare, but if it occurs, it may be treated with steroids tablets.
  • Liver - radiation treatment to the liver may cause abnormalities in blood tests of liver function. This may appear weeks after the treatment. You will have regular blood tests to monitor your liver function. Should this occur, you may be treated with steroids or you may just be monitored until it subsides. This rare side effect can be fatal in a small number of cases.
  • Cholecystitis - inflammation of the gallbladder can result from the radiation, although this is very unusual. Normally this will resolve without treatment, but if it persists, it is possible to remove the gall bladder in an operation 2-3 months after the microsphere treatment.

The potential long-term risk from these radiation doses is uncertain. However, as long as the radiation is confined to your liver, the side effects are usually mild. Any exposure to radiation has the potential for long-term damage such as scarring of the liver or a small risk of other malignancies developing many years later, but this risk is small and cannot be measured.



In clinic, the Precision Oncology Consultant will provide a thorough consultation and fully explain the treatment procedure, the benefits and any potential side effects or risks. All cases are discussed with the Multi-disciplinary Team, with whom we work closely to ensure you have easily accessible support during and after your treatment.



Further Information



NICE Guidance states that SIRT can prolong time to progression of hepatic metastasis patients previously treated with chemotherapy. For patients who have not previously received chemotherapy, the effectiveness of the treatment has not been proven. All relevant clinical information is entered on a national SIRT Registry.



Further information can be found on the following websites:
www.sirt.org.uk
www.mysirtstory.org.uk
www.nice.org.uk
http://cancerhelp.cancerresearchuk.org
www.macmillan.org.uk