Journal of Thoracic Oncology:
Poster Abstracts: Novel Therapeutics:New Horizon and Others: NT: Radiation Posters, Wed, Sept 5 - Thur, Sept 6
MAASTRO Clinic, GROW, University Hospital Maastricht, Maastricht, The Netherlands
The prognosis of patients with NSCLC is still poor. Amongst distant metastases, also local tumour recurrence is still a problem. Because charged particles (protons and C-ions) have a better dose-distribution than the currently used photons, at least from a theoretical point of view, they should lead to superior results compared to photons. On top of the physical superiority of protons over photons, C-ions also display a biological advantage.
In this review, we searched for clinical evidence that protons or C-ions would really be beneficial to patients with NSCLC.
We performed a review based on published literature by means of a standardized query using the following electronic databases (up until January 31, 2007): CINAHL, EMBASE and MEDLINE. There was no limit applied to publication year, language or study design. Search terms (using free text words as well as MESH terms) were used alone or in combination, related to lung cancer and charged particle treatment. This included the following terms: neoplasm, cancer, carcinoma, lung cancer, proton, ion, charged particle and hadron.
Six fully published series (protons:3, C-ions:3), all dealing with NSCLC, mainly stage I, were identified. No phase III trials could be identified. On proton therapy, weighted means of 2-5 year local tumour control rates varied between 68% and 84%. The weighted mean for 2 year/5 year overall survival and 2 year/5 year cause specific survival were 53%/23% and 66%/46% respectively. Radiation induced pneumonitis was observed in about 10% of the patients. On C-ion therapy, the local tumour control rate was 77% and the 5 year overall survival and cause specific survival rates were 42% and 60% respectively.
The results with charged particles, at least for stage I disease, seem to be better than that which is generally achieved by conventional radiotherapy. However, they seem to be similar to what may be achieved with hypofractionated “stereotactic" photon techniques, with which in several phase I/II studies, local tumour control rates of 90 % and more were reported. Due to the overwhelming theoretical data on the beneficial properties of protons and light ions, further investment in the infrastructure needed to perform large trials in patients with different lung cancer stages, is warranted.
Until these results are available, for lung cancer, charged particle therapy should be considered as experimental.
Copyright © 2007 by the European Lung Cancer Conference and the International Association for the Study of Lung Cancer.