Cyberknife vs. cancer

Cancer treatment with radiosurgery method – Cyberknife

“In fact, we want to treat better, more efficiently, in a way that is more convenient and easier for patients. We want to help those who are undergoing treatment, but the effects of a severe illness persist, and these issues were impossible to solve using the resources available in Latvia until now.
Actually, modern technology CyberKnife shoud be applied in all cases when necessary,” says Dr. Dace Saukuma and Dr. Māris Mežeckis, radiation therapists of SIA Sigulda slimnīca.

Both colleagues have considerable experience in treatment of cancer patients. Dr. Saukuma has worked as a radiation therapist for more than 10 years, she is the chief physician of the Radiosurgery Department in the Oncology Centre of Latvia, and has worked in the field of radiosurgery since 2010. Dr. Mežeckis was the head of Radiosurgery Department in Liepaja Regional Hospital and has given special attention to treatment of prostate tumors. They both have mastered CyberKnife technology in the USA and Italy.

The Stereotactic Radiosurgery Centre was opened in Sigulda Hospital at the end of last year; this is the place where malignant and benign tumours can be treated with robotic stereotactic radiosurgery equipment of the latest generation CyberKnife M6 – in other words, with cyberknife. Tumour cells can be destroyed without surgical intervention using very accurate, precisely aimed ionising radiation. So far, this device is not available in other Baltic States.

First of all, please tell us about the technique!

Dace Saukuma: American neurosurgeon John Adler invented the device (in 1994 at the University of Stanford). The first patients were treated in the USA using CyberKnife of the first generation in 1999, in Europe the first centre with CyberKnife device was established  in 2002 in Italy, and in 2003 – in Germany. Sigulda Radiosurgery Centre is currently the most modern centre in Eastern Europe. 40 patients underwent treatment using CyberKnife in the first nine months. In December last year we began to treat benign and malignant brain tumours and metastases in the head. In February, we continued to apply the technique to treat tumours in the spine, in June – in the prostate, and now we have mastered the technique so that we can treat small primary tumours and metastases throughout the body – in the liver, kidneys, adrenal glandss, pancreas, and lungs. If necessary, this technique can be combined with other kinds of treatment.

How do patients get to you?

D.S.: In different ways. In most cases diagnostics and partly treatment is carried out in other healthcare facilities. The initial tumour in some patients was often cured three or four years ago – the primary tumour was removed, they had local radiation therapy and chemotherapy, however, despite all efforts, the disease continues to progress and new metastases occur. If metastases occur in different organs, it is quite difficult to surgically remove them, and it means the patient has to undergo several surgeries. CyberKnife can help without incisions.

Māris Mežeckis: There are situations when CyberKnife is the treatment of the first choice. For example, in patients with the first or second stage of prostate cancer which has not spread yet. In such cases a urologist usually offers not to undergo surgery at once and observe the progress of the disease by undergoing regular check-ups. For men, surgery is a comparatively difficult treatment with a rather long period of recovery. Most patients have issues related to urine incontinence and impotence after surgery. However, some patients believe it is unacceptable to delay the surgery, as the tumour can continue growing for one or two years and even cause remote metastases. Moreover, some patients find is difficult to live with this diagnosis and know that they have cancer, it can be psychologically depressing… In this case, CyberKnife is a good solution: we carry out the manipulation which is as effective as surgery – we destroy tumour cells, remove the tumour, and the result is ensured not by an incision, but by high-dose highly-accurate ionising radiation. It usually involves five radiation sessions or fractions – this technique has been relatively well-proven in the world. The treatment is performed in an out-patient’s facility. Now a patient comes to our centre five days in a row, and each procedure lasts about 40 minutes.

D.S.: To eliminate small tumours and metastases in other organs, the dose of ionising radiation is given during 1-5 sessions. For example, small tumours in the liver, head and lung periphery can usually be destroyed by one radiation fraction.

What about side effects, as a patient is exposed to radiation?

M.M.: It depends on the organ in which cancer cells are destroyed. If it is the prostate, side effects are similar to classic radiation, but the acute period begins faster and ends faster after CyberKnife procedure. When the prostate is exposed to radiation, adjacent organs and surrounding tissues slightly suffer from this ionising radiation – urethra is irritated, patients may experience burning sensation during urination or discomfort in the urinary bladder. Diarrhoea may sometimes occur, as the prostate is located near the intestinal wall. Side effects occur within a week after the beginning of the therapy, they can last at most two or three weeks, and it takes two to three months until they completely disappear. We say to our patients: if there are even the slightest complaints, please call us at once – if we can somehow improve their situation, their well-being, we will immediately do it.

Men certainly wonder what will happen to potency after treatment with CyberKnife

M.M.: It decreased by 10-15% on average. In fact, potency after prostate radiosurgery depends on many factors: stage of the patient’s disease, whether the patient has received hormone therapy, and, most importantly, on potency before the treatment. If potency has slightly decreased, most often it can be compensated by respective drugs or other methods.

How is this procedure performed?

M.M.: First the patient should be prepared for it – special golden markers are placed in the target organ so that the device can accurately focus the light beam. It is similar to biopsy, but in case of biopsy a needle is inserted into the prostate to take tissue samples, but we are doing the opposite – we insert the needle and leave golden markers which are 2-4 mm large. Markers are necessary, since the prostate moves by several millimetres due to the functioning intestines. During the classical radiation therapy, in order to destroy the prostate cancer cells, a small-dose radiation is used on a much larger area, but in our case, a large dose which should precisely hit the target.

A patient also attends Diamed or Orto clinics which make special computed tomography and magnetic resonance images that enable us to see where exactly the prostate is located in the pelvis. Then, a radiation therapist marks the area to be exposed to radiation and adjacent organs, and determines the planned dose, and a physicist plans and checks light beams of rays in order to hit the tumour with a dose that will destroy it and to spare surrounding organs as much as possible. Then the patient comes to the clinic for the procedure, during which he lies quietly on the therapeutic table in a special vacuum bag that holds him in a stable position, and the rest is performed by the device overseen by a radiology assistant, physician and medical physicist. The source of rays CyberKnife – linear accelerator – moves around the patient under a special programme and transmits precise beams of rays. The robotic arm delivers beam of rays under almost any angle, moreover, it takes into account the position of the prostate tumour or another tumour at a specific moment. The changes are insignificant in the surrounding tissues through which one ray has passed through, but the effect is summed up in the point of intersection thus destroying the tumour cells. CyberKnife can emit beams of rays to the area to be destroyed under up to 1,200 different angles.

How accurate is the Sigulda CyberKnife, what is the smallest area it can influence?

D.S.: The smallest size of the target is 3-4 millimeters. In case of trigeminal neuralgia it can be a few millimetre large, and the entire prostate is exposed in case of prostate tumour. This method is the most effective when the tumour size is less than 3.5 centimetres. Situations when we can provide therapy to tumours up to 5 cm in diameter are less common. However, there are no strict specific figures – everything depends on the specific clinical situation: how many tumours are there, where are they located, in what part of the body. For example, the maximum number is three metastases in the liver, but there may be four to six metastases, but their diameter should be smaller.

What should patients bring to the consultation?

D.S.: The results of all previous examinations over the past few years. And, in there is a tumour, all diagnostic examinations and excerpts related to treatment from the beginning up to the present moment. To make a decision regarding the application of radiosurgery, the information about other diseases is also very important – myocardial infarction, stroke, chronic diseases. Blood tests should be done two months before the procedure.

What is the guarantee of the procedure efficiency?

D.S.: To be sure that radiation therapy will be efficient, we recommend the patient to undergo positron emission tomography (PET/CT) – this examination is a full-body scan which gives clear and accurate information about dissemination and stage of the tumor. We must be absolutely sure that the tumour is really at the first stage, not the third or fourth stage, and that it has not spread beyond the area of the primary tumour localisation.

M.M.: PET/CT examination allow targeting the treatment more accurately, as this examination shows the activity level of cellular metabolism when the tissues are not visually changed for computed tomography. This method allows finding tumour dissemination, when it is still not visible for computed tomography and magnetic resonance imaging, and it sometimes allows ruling out the nodes that visually changed, but don’t actually contain tumour cells.

It is also important to assess the effectiveness of therapy after it is completed by evaluating the metabolic activity of the respective neoplasm in PET/CT to find out whether there is any malignant activity in the tissues. If there are no changes in the laboratory tests and PET/CT findings after the therapy, it means that cancer-related issue has been solved for the patient at this particular moment.

D.S.: In case of unclear clinical situations we can invite the best consultants. For example, Vladislav Burik, associated processor from Ukraine, gives us valuable advice in case of tumours in the head and spine. He is an expert in neuroradiology and has 6-year experience with CyberKnife in Ukraine, and he had been an operating neurosurgeon for many years before that. If the cancer has spread to the lungs, we consult thoracic surgeons. If the treatment is required for the liver, we involve invasive radiologists or oncologic surgeons and medical oncologists.

As to other benefits of treatment using the CyberKnife…

Patient’s everyday activities are not interrupted, and no one on the outside will know that this person is undergoing treatment. If necessary, we issue a sick leave certificate. In our clinic, the patient’s health issue is confidential information. It is much easier to ensure the privacy here than in a large hospital, where a patient can be recognised in the hallway of a department. Our centre, which is a part of Sigulda Hospital, is located in a separate building.

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