World Congress on Gastrointestinal Cancer 14, Barcelona, Spain
Advances in radiotherapy for rectal cancer
Dr Karin Haustermans – University Hospital Leuven, Belgium
What important developments in rectal cancer were highlighted at the ESMO 14th WCGC?
In rectal cancer there are several important developments. First of all we have our screening programmes, so we detect rectal cancer at a much earlier stage, so the question is: do we have to treat these patients in the same way as we treat patients with locally advanced cancer? Probably we do not, probably a local excision in most of these patients is sufficient to cure them and it is, of course, a major step forwards because that way leads to more organ preservation and less side effects. That’s for the early cancers; for the more advanced stages we now introduce functional imaging in our decision process. This means that we do PET CT scans and diffusion weighted MRI in these patients before the start of treatment and after ten fractions of chemoradiation, then we look at how the tumour responds to the chemoradiation and in about half of these patients we see a very good response to this treatment. For these patients we can probably also go for organ saving techniques, maybe these patients don’t even need an operation and can just be followed after the chemoradiation. The other half of the patients, unfortunately they do not respond very well and so in these patients we have to look for treatment intensification and there we have several possibilities. Either we increase the dose of radiation or we add more drugs to the treatment, combined with the radiation, or in the interval after the end of the chemoradiation and the surgery.
Have there been any changes to how or when you give radiotherapy for rectal cancer?
Classically we go for a long course of chemoradiation which means 25-28 fractions of radiotherapy with an overall treatment duration of 5-5½ weeks. But now more and more people are looking into giving a short course of radiotherapy, only 5 fractions, only one week, and then wait for 6-8 weeks before going to surgery. It might be that patients that are treated with a short course of radiotherapy respond as well as patients treated with a long course of chemoradiotherapy. The advantage of going for a short course of radiotherapy is that during the interval before surgery there is the possibility to give full dose chemotherapy to these patients. We see that in locally advanced cancer most of the patients die of metastases so systemic disease is becoming more of a problem than the local recurrence or the local problem.
Can you overview what the session on multimodal treatment for rectal cancer will cover?
During the session we will have a radiologist talking on the different imaging modalities. She will mainly focus on MRI and the future of MRI to play a more and more important role in the treatment of the disease. Then we will have two surgeons discussing the role of organ preservation for locally advanced tumours but also for the early cancers. Then I will talk on the new developments in the field of radiotherapy, how techniques are evolving and then we will have a speaker on how to schedule chemotherapy, radiotherapy in the pre-op setting, in the post-op setting, and we’ll have a speaker talking on the need for post-operative chemotherapy in patients that respond well to pre-op chemoradiotherapy or in patients that do not respond well to pre-op chemoradiotherapy.
What are some of the new radiotherapy approaches you will be speaking about?
First of all the introduction of functional imaging in our treatment process and we use functional imaging to better delineate our target for radiation and also to follow the tumour during treatment so that we can adapt our radiotherapy and use shrinking volumes during treatment. That’s one aspect, the other aspect is that, of course, technology is also evolving and we have newer machines available to treat our patients, machines that integrate MRI, so a linear accelerator combined with an MRI. This allows us to follow the tumour even during the delivery of the radiotherapy and adapt the treatment.
How are these new approaches making their way into clinical practice?
That, of course, needs time. These are all preliminary studies, they are hypothesis generating and then, of course, we need the multi-centre trials to validate these techniques. These will be rather prospective studies than randomised trials as it is very difficult to randomise patients between the standard arm and the new treatment approach with, very likely, a better outcome than the standard treatment.
Are there any other data you would like to highlight?
This has been a very interesting meeting. Yesterday we had very interesting sessions on oesophageal cancer, GE junction cancer and stomach cancer. It is clear that we are moving more and more into the field of personalised treatment, of characterisation of the tumours and adapt treatment according to the molecular characteristics of the tumours.