Future Horizons in Lung Cancer

Current state of the art radiotherapy in lung cancer

Prof Corinne Faivre-Finn - The Christie NHS Foundation Trust, Manchester, UK

I’m giving a talk on state of the art radiotherapy in lung cancer and a lot has happened in the last decade in terms of advanced radiotherapy techniques which have translated into improvement in local control and also survival in lung cancer patients. So I’m going to focus on three aspects in my talk, one is SABR treatment, so stereotactic ablative body radiotherapy for early stage non-small cell lung cancer. I’m also going to talk about locally advanced non-small cell lung cancer, where unfortunately less progress has been made, and the last part of my talk is on limited stage small cell lung cancer and I’m going to talk about a study I presented at ASCO aiming to establish a standard of care in this group of patients.

What are the benefits of SABR?

SABR involves the use of very high dose hyperfractionated radiotherapy, so hyperfractionated means that we’re delivering a small number of fractions, so typically 3-8 as opposed to 20-33 with conventional radiotherapy. So it is a treatment that is very convenient for patients, also for the radiotherapy department. The treatment compared to standard forms of radiotherapy works much better so the local control is around 90% compared to less than 50% with standard forms of radiotherapy.

This has been studied and tested quite extensively and used extensively?

A number of prospective studies have been reported, unfortunately to date we have no randomised controlled trial comparing SABR to either best supportive care or standard forms of radiotherapy or surgery. There are studies that are currently recruiting patients, some have recently completed but we have no randomised data. However, given the excellent results published so far in prospective studies, SABR is now accepted as a standard of care in this group of patients providing that they are medically inoperable. So the majority of international guidelines will now recommend SABR as a standard treatment. In patients who are operable surgery remains the standard of care.

Can you tell me about the work you presented at ASCO?

I presented the CONVERT study which is an international phase III trial comparing the standard treatment in this disease, which is twice-daily radiotherapy given concurrently with chemotherapy, to a higher dose of radiotherapy given once a day, again with concurrent chemo-radiotherapy. So this study showed that there was no difference in survival between the two arms, however, survival in both arms was much higher than previously reported and importantly toxicity was much lower than previously reported. So one of the toxicities that most oncologists are very concerned about with radiation is oesophagitis and if severe this can lead to hospitalisation and poor quality of life. So our study showed a reduction in 50% in the rate of severe oesophagitis compared to previous studies.

The implication is that twice daily radiotherapy, which is the control arm of the study, should remain the standard of care given that CONVERT was not an equivalence trial. However, I still think that it is reasonable to offer once daily radiotherapy if patients do not wish to travel twice a day to have their treatment or if, from a logistical point of view, the radiotherapy department cannot deliver twice-daily radiotherapy given that there is very little difference in survival between the two arms and toxicity is the same in both arms.

Anything else to mention on lung radiotherapy?

In stage 3 non-small cell lung cancer or locally advanced non-small cell lung cancer unfortunately very little progress has been made in the last twenty years. Particularly we are not able to personalise treatments in this group of patients. We know that in stage 4 disease we can take into account histology, driver mutations, to tailor the treatment that is delivered to the patients. That is not the case in stage 3 disease. So far none of the studies have shown that we should take into account the anatomical location, the volume of the disease, driver mutations, histology, to tailor the treatment. There are studies ongoing that may answer these questions.