In the early 1970s, the net adjusted survival at one year was 50%. This meant that in the 1990s, 50% of cancer patients lived 5 years, and in the most contemporary data evaluation, that figure reached 10 years, meaning we have multiplied for 10 the survival of the patients with cancer. This is palpable stage by stage, disease by disease, in almost all circumstances.
In practical terms, this means that the patients are living longer with cancer and that cancer is becoming a chronic disease. Because of this, we are beginning to see a number of patients with early metastatic disease and also early first diagnosis with minimal disease. This means that on one hand, aggressive treatments, mutilating treatments, that were considered in the past standard of care are no longer valid.
On the other hand, a patient that has early metastatic disease should not be labeled as palliative or terminal and an non-healistic approach is not considered valid any longer. Also, because the explosion in the technology of the radiological detection tools such as CT scan, MRI's, PET scans, etc., we are able to diagnose cancer at a much earlier stage. As I said before, we can diagnose not only in primary presentation but also in early metastatic disease.
There are a number of new treatment modalities arising from the radiation therapy standpoint. I will introduce a few on this editorial and complete it by next month’s editorial.
This new treatment modality can address and treat tumors with high precision, high accuracy, and minimal side effects at early disease. It is called stereotactic radiosurgery and is, in essence, the ability with new technology to deliver a high dose of radiation therapy in 1 or up to 5 fractions with the precision of 1 mm in the setup and treatment delivery, meaning 1 treatment session or up to 5 treatment sessions compared to the traditional timings of 5 to 10 weeks of treatment.
The scientific literature is beginning to be inundated with reports from large, private practice clinician groups as well as academic institutions who are putting those treatments on the map and are beginning to be considered first choice in the management of a number of cancer diseases as I will relate later in this editorial.
It is important to know that there is numerous, advanced technology, which we should technically call them treatment platforms, which can deliver treatments with the accuracy and precision of 1 mm. Here is a description of all of them. They are not all exactly interchangeable, however the vast majority can do the same job.
It is important to note that many specialists recommend patients to receive, access treatment with the “gamma knife” in the U.S., however what they are recommending is either stereotactic radiosurgery or stereoctactic body radiation therapy, also known as SRS or SBRT. The gamma knife is a dated technology invented in the 1950s which delivers just what I describe – high doses of radiation with this exact precision.
Today, this same treatment is delivered with the gamma knife still, a linear accelerator and most sophisticated technology, the Cyberknife. I will explain the function of the latter two technologies.
The first technology of the latest generation is the linear accelerator, this is the traditional radiation therapy machine that has the capability to deliver stereotactic radiosurgery. The treatment, as I said in my intro, can be delivered with 1 mm accuracy and has an internal imaging system that allows for verification of the positioning prior to the treatment and during the treatment with the accuracy of 1 mm, as quality assurance and control is key. In order to do this, the linear accelerator must have an external imaging system, called online board imager, also known as OBI. It is particularly effective against small, well-defined tumors in inoperable or surgically risky locations such as the brain and spine.
Cyberknife Technology Photo
The second technology is called the CyberKnife. This machine is the first to have a robotic arm that was adapted for medical uses from its original conception in the automobile industry where it was used in the car assembly lines to do arc welding. This robotic arm has a 6-degree of freedom, which means that it can move in every direction, allowing more flexibility, and on the head of the machine, instead of a laser or a welding system, we have a small linear accelerator.
The CyberKnife system also has external x-ray guidance that allows for patient positioning, patient tracking together with a computer system which can retrofit the robotic arm and correct the trajectory of the treatment delivery if the patient has moved, very sophisticated.
These treatment modalities deliver high doses of radiation with microscopic precision, making it a good option for some patients with inoperable or surgically risky tumors. It is a non-invasive alternative to surgery for the treatment of certain tumors.
I will introduce a couple of other technologies on next month’s editorial together with which patients and indications would be appropriate for these treatments – for stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT).