Stereotactic radiosurgery involves the application of a very high radiation dose onto a small area – a neoplastic tumour. This way, neoplastic cells are destroyed and cell necrosis is achieved. Hence, it is a prerequisite of stereotactic radiosurgery (stereotaxy) for the tumour to be of minor size and have a location that affords the application of a radiation dose while bypassing healthy organs that are to be left intact. Traditional radiation therapy affects a larger area covering healthy organs, the radiation dose is administered over a longer period and the healthy tissues are still able to recover, even though they are exposed to considerable radiation dose.
Alternative to surgery
In some cases such a therapy may be considered as an alternative to traditional surgical procedure and the efficacy of both methods is comparable under such circumstances. An indication for stereotactic radiosurgery is, for instance, lung tumour, both primary and metastatic. Upon the validation of eligibility for this treatment the following considerations must be taken into account: the location of the tumour, disease advancement and the patient’s condition. Stereotactic radiation therapy is employed whenever the location of the tumour makes it difficult or impossible to access the tumour during surgery. This method is also used in patients whose health condition does not allow traditional surgery such as senior people. The treatment is also applied in patients who have developed chronic obstructive lung disease apart from tumours in lungs and their lungs are in a condition that does not allow a traditional surgery.
Most common application
Stereotaxy is mostly used in case of tumours located in lungs, brain, liver, prostate and bones. In case of lung and prostate tumours, radical therapy of the primary cancer of the organ is a common indication. In other locations, metastatic lesions are more likely to be treated, e.g., to liver or bones. Stereotactic radiosurgery proves effective in both primary and secondary lesions, with good results especially in brain tumours as their surgical access usually poses a significant challenge. This procedure also brings a promise of cure to patients who would have been subjected only to palliative care several years ago. This pertains to patients who have been diagnosed with a restricted diffusion of disease in multiple sites. In not such a distant past a patient of this sort would not have undergone a surgery or radiation therapy due to poor prognosis. Nowadays, by virtue of better diagnostics, we may identify all disease foci and attempt radical treatment. Today, such patients may be treated precisely by means of stereotactic radiosurgery.
Identification of tumour location
It is of utmost importance in the validation of eligibility for this method to accurately determine the location of the tumour and the development stage of the disease, which is why PET examination is always performed prior to irradiation. PET accurately shows the number and location of disease foci. Stereotactic radiosurgery is carried out when there is a limited number of metastatic foci. The most common upper boundary is 5 lesions. The procedure required immense precision. For this reason, the patient must be steadily immobilized and the patient’s position must be continuously monitored throughout irradiation. The procedures last from 15 to 30 minutes, depending on radiation dose. Each subject must be primed for the procedure in a meticulous way. Even the patient’s mobility that is associated with breathing during the procedure must be anticipated and considered in the treatment plan. The procedure may be interrupted to revalidate the patient’s position, if the preservation of the precision of radiation targeting so requires. Such radiation sessions must be repeated 3 or 5 times a few days apart from each other. The therapy usually spans a week or a fortnight. The treatment is reimbursed by the National Health Fund.