ESTRO 2010, 12-16 September, Barcelona
Professor Luca Cozzi - Oncology Institute of Southern Switzerland, Bellinzona, Switzerland
The benefits of RapidArc and other new radiosurgery technologies
You’re talking a lot of research and stuff but particularly you’re demonstrating how this RapidArc stuff works. What’s all this about?
Well RapidArc was a rather innovative way of delivering rotational therapy that is a very old concept in radiation oncology but never came to good practice because of technical difficulties. So once these were solved we got a very powerful tool to deliver extremely focussed dose distributions to the patient and we got the possibility to spare organs at risk much more than before. So this is the background of RapidArc.
How do you spare organs?
Sparing the dose to the organs at risk because rotating the machine around the body just on a podium in the theatre, you can spot the light on the actor and then the rest is in the shadows. This is the principle.
The second very important pillar that we got as a technical benefit was speed. Delivery time, depending on the technology, but it is rather a long process in radiotherapy. The dose fraction takes normally now fifteen, twenty minutes for the very complicated deliveries, up to 50/90. This is extremely long and the patient has to stay on the couch that is uncomfortable, they have pain and they move; since they are breathing internal organs are moving, etc. So this new technology allowed us to drop dramatically the time, down to, for normal fractions, about two minutes or less for a single fraction; for hyperfractionated treatments or stereotactical treatments we can deliver within ten minutes very high dose levels. So organ movement is still there but can be managed quite efficiently, breathing can be managed quite efficiently. So combining the focalisation and the speed we opened also new treatment sites that were considered not really effective for radiotherapy.
Such as?
Such as, for example, advanced lung cancer that with conventional radiotherapy is often treated with insufficient dose. Now there are centres escalating the dose up to 70 - 72Grays that are still in the progress of becoming adequate but at least we can control much better the disease we are getting. For example, there is a centre in Italy, the Humanitas Institute near Milan in Rozzano, they are treating several centres in co-operation with my institute and the ratio of shrinkage of the tumour is now about 50% of the patients are experiencing, not a complete remission, but a near to complete remission. So these patients will live longer and we are now capable of managing their disease for a much longer time. We can then also control metastases and collateral complications.
Can you operate in those lung tumours after?
Eventually it can be operated or if the regrowth appears after complete remission, that will be very small and we will be able to treat it still with RapidArc under stereotactical conditions and deliver really high boost doses to the new focus and to eventually eradicate it.
Other indications that we are now treating are oligometastases in the abdomen with stereotactical conditions. So these are tumours or metastases that are appearing here and there in the abdomen so you can deliver a very focussed dose and once more we are prolonging the life of these patients and we are hoping to then control systemically the disease.
So these were indications that were always present but badly treated. Other indications that are coming new to the field or coming back to the field are, for example, liver cancer. Toxicity in the liver is extremely high when you deliver radiation so, as I mentioned before, RapidArc allows you to reduce the dose to the LT structures so now we can focus the dose to the liver and try to obliterate the tumour completely and to let the rest of the liver be sufficiently healthy to recover. So these are new indications and all the rest is clearly treated.
There’s a new word I’ve learned since I came to ESTRO a couple of days ago, and that’s radiosurgery. This is interesting. I’m not a surgeon by the way.
It’s an interesting concept of surgery delivered by non-surgeons. This is the way of focussing the dose with a very sharp dose fall-off. So ideally zero dose outside the target and maximum inside the target, and this has to be applied for very small tumours because early stages or brain tumours, but even benign diseases in the brain like schwannomas or meningiomas are subject to this kind of treatment. Once more, speed and limited dose outside is the key factor. In this way one small lung cancer is becoming a dominant effect, early stage 1, some stage 2 can be treated with RapidArc and doses up to three times 18 Grays. If you think radiobiologically, this is a tremendous dose, near to 80 - 100 Grays delivered.
So you’re giving three fractions a round?
Three fractions of 18 Grays and this might clearly cure and control completely the local tumour and then the patient is open for the rest of the treatment.
What I’m not seeing here are many randomised trials. I’m not seeing Gamma Knife versus Cyberknife; I’m not seeing Cyberknife versus RapidArc; I’m not seeing RapidArc versus HIFU in the liver metastases, for instance. When is this going to come because we need some evidence?
Yes, this is something that in traditional oncology is still missing, the concept of randomised techniques. What we are randomising standard are the dose prescriptions, the pathways of care but not the technology used. This derives, probably, from an ethical concern – when you have a technique that you feel is, by physics, better then you are scared about offering a randomised trial. This came, for example, in the protons community; protons are considered to be so superior from the physics that hardly an ethical committee will accept a randomised trial, photons against protons. So this is the background and probably this goes in the game for these new technologies like RapidArc, Cyberknife or Tomo.
But I fully agree with you because here we don’t have the evidence based on randomised trials. What we are trying to do, and these are coming now, my group, for example, is doing this for cervix cancer, is to make mixed pair analyses with historical groups of patients treated with different modalities and equivalent patients carefully matched with the new technique. This is not the equivalent of a randomised trial but it is a good approximation of it. The first evidence came from Amsterdam on lung cancer, they compared stereotactical treatments with conventional methods and RapidArc and they published it in the Journal of Clinical Oncology this year. They showed that the pattern of toxicity in terms of lung capacity was equivalent. This was a sort of phase I trial to demonstrate the absence of toxicity. So I guess these kinds of studies will be easier rather than doing a real randomised trial.
But we’d like the randomised trials too, please, eventually.
Yes, eventually that would be ideal, but also the cost of these kinds of trials is quite…
Exactly but the cost of the therapies is also a problem. What the public health systems and the governments around Europe are saying now is, “OK, these are expensive new equipments, tell us what the savings are.” You can do it in three fractions instead of six weeks, for instance, is that saving or not? And what about the patients, have you done the randomised studies looking at the quality of life and that sort of thing? Because I think more and more now governments are listening to the patients.
Absolutely. Well, there is a bit of difference between chemotherapies and radiation therapies because in our field the cost comes from the capital investment then the running costs are really limited, mostly to the personal cost and not to the machines themselves any more. So there is a different bias in this framework but yes, I fully agree, we need randomised trials. It will be difficult to set up and so probably matched pair analysis will be providing some sort of evidence at lower level.
Yes, but to go to one extreme, if you’re going to build a hadron facility, that’s a serious capital investment and if you’re the government, trying to get that money back, you need some data. The criticism of the hadron explosion in the United States is there’s no evidence.
There’s no evidence in that sense, yes. For these new technologies like RapidArc, what can be easily proven in terms of cost effectiveness is the reduction of waiting lists due to the higher efficiency and to the possibility to treat more types of tumours, as I mentioned before, that were not considered to be interesting for radiotherapy before. So these areas are economical aspects for the management of hospitals in terms that you can pay back the technology by treating more patients or to cut the collateral cost of the care path if you don’t treat them fast. So one aspect is probably covered, the other we have to do our homework.
ESTRO in two years’ time, we’ll get the results of some of these trials.
I hope so.
Thank you very much indeed.
