European Multidisciplinary Conference in Thoracic Oncology (EMCTO 2011) 24—26th February 2011, Lugano
Stereotactic radiosurgery for stage I non-small cell lung cancer
Dr Rafal Dziadziuszko – Medical University of Gdansk, Poland
Professor Rafal Dziadziuszko, you have what is described as a treatment giving a high impact on survival in patients with early lung cancer. Now in your section of the conference you’re talking on what is the optimal care for patients with stage 1-3 non-small cell lung cancer. Let me ask you – what is it, from the radiation oncologist’s point of view?
During my presentation I will be focussing on some aspects of radiation therapy for early non-small cell lung cancer. I will start with the description of outcomes of patients treated with stereotactic radiotherapy for early lung cancer. This is an exciting topic for many oncologists because the technique was developed in thoracic malignancies since about 2000 and now we are beginning to understand what its impact on lung cancer survival is.
Now it looks as if it may have a big impact; it’s very recent and it gives the possibility of getting much finer margins, doesn’t it?
Yes, indeed. This technology was originally developed for brain tumours and since the time we understood that it may be used also for thoracic tumours with very small margins, high precision and very high dose per fraction, which is simply not possible through conventional radiation oncology techniques like, for example, conformal radiotherapy. Outcomes of patients treated with this technology have been presented during the last three years in larger series of patients and we now understand that the local control is excellent, like 10% local relapse rate, which is indeed comparable to what surgeons would experience in their series of operable patients. Now the technology is used mainly for medically inoperable lung cancer patients; that means those patients who cannot undergo surgery. However, there are also numerous attempts to compare this technology with open surgery or with any kind of surgery. Of course, whether this will indeed be used in surgical patients or not will be a matter of next generation research projects.
Let me ask you though, which patients, specifically, would you use stereotactic radiotherapy in? Because you’ve got to define the tumour very precisely and then if you hit it hard enough you can kill the cancer.
Yes indeed. What matters is very adequate staging; you have to have local disease with no regional, meaning mediastinal or higher lymph nodes, involved. And you have to have tumours that are generally not more than 5cm, although there were also several series of selected patients with higher primary disease volumes.
But basically it needs to be stage 1, not stage 2 or 3?
Yes, exactly. Also, it’s very important to have very well defined staging based on PET scanning and assessment of lymph nodes by EBUS or EUS, meaning… and the bronchial, and as a fragile ultrasound and any other technique that is important for staging has to be very well-adapted here to make sure that we are dealing really with stage 1 non-small cell lung cancer.
Now you said that it needs to be given to patients who are basically inoperable, now that gives you a dilemma, doesn’t it? You have a patient, first of all you’ve got to decide on whether it’s resectable.
You know, for now it’s quite obvious because in most European institutions we practise multidisciplinarity. So we meet with other physicians, thoracic surgeons, radiologists, pulmonologists and so on to discuss the patient and it’s quite obvious, based on performance, age, comorbidities and so on, for most of the patients who should be treated with standard of care, which is surgery, and who may benefit from this procedure because the risks of surgical procedure are too high.
How difficult is it to give stereotactic radiotherapy though, because you’ve got to have a patient who doesn’t move?
Yes. The problem is that to obtain a reliable treatment plan, you have to adapt a number of quality assured procedures in your radiation therapy department. First of all, during treatment planning you have to precisely know how the tumour moves. To achieve this point what is called a four dimensional CT scan is essential; that means that you are able to obtain the tumour motion picture after you have your CT scans and you account for that in your planning of radiation therapy. So once you’ve registered how the tumour looks and how it moves during respiration, you just… as minimal margin as possible, meaning treat to 5mm and you irradiate this to a very high dose.
Is it suitable for treating all tumours, does it matter about the location?
That’s a very good point. For now on it’s not. For centrally located tumours we have a problem because in a series of patients that have been published there has been some increased toxicity, including fatal toxicities, so clinical trials to answer the question of how we should fractionate centrally located tumours are on-going and are very promising.
Does this all add up to the need for a centre of excellence for doing this or do you think this can be used in most centres?
I think that for now we have to have very well-defined radiation oncology centres to start such a procedure because it needs a very extensive quality assurance programme. So I don’t think that it will be cost-effective to do it in every radiation oncology facility in the country. For example, in Poland, where I practise, we have about four or five centres that are doing stereotactic radiation therapy for early lung cancer and other centres are referring patients to us. The volume of patients is not so high so we can actually achieve this goal within a limited number of centres.
Now, in non-small cell lung cancer you’ve been using it for ten years or so, long term results are awaited of course, but you intimated that there could be a big impact on survival. Now I know you don’t have the data yet, but how big an impact are you looking for?
There has been a very nice publication from the group of three universities from Amsterdam; actually this group pioneered stereotactic body radiation therapy in Europe, together with colleagues from Karolinska and other institutions. This group has very nicely shown that in their very well defined cancer registries, implementation of stereotactic radiotherapy for early non-small cell lung cancer has impacted survival from the epidemiological perspective. I was talking to my colleague, Dr Suresh Senan, this morning about this important landmark paper and he told me that they are looking for their global picture in the Netherlands to see how much it impacts on outcomes after the procedure was introduced. And it looks like it’s really a huge impact.
In percentage terms, then, in both quality and length of life, what might that be?
First of all the length of life, just a percentage of cured patients with early stage increased by something like, if I recall correctly, between 15-20% which is a remarkable thing especially in this population of patients for whom traditionally surgery was contra-indicated for a number of reasons.
And therefore no cure, automatically?
And we have been treating those patients with traditional radiotherapy which has limited long term outcome impact.
What should doctors be remembering from this?
If any physician sees an early lung cancer patient that is not suitable for surgery from comorbidities, age or any other reason, the patient should definitely be considered as a candidate for stereotactic radiotherapy rather than conventional 3D radiotherapy or any other treatments.
And you did mention toxicities that are still being examined, are there any risks?
Actually there are a number of toxicities but once you have the procedure well developed and you pay attention to what we know about this technology, it seems that the risk of serious toxicity is really limited, certainly not more than for traditional conformal radiotherapy. The toxicities are different and careful treatment planning is essential to achieve the measures to minimize toxicity. According to a well-defined series of patients, major toxicities occur in less than 10% of patients, which is a very good outcome for such a treatment.
So what you’re saying, in a nutshell, is that radiation is a powerful curative modality?
Professor Dziadziuszko, thank you very much indeed. It’s great to hear from you and we look forward to hearing more about this.