Systematic review and meta-analysis of radiotherapy in various head and neck cancers: comparing photons, carbon-ions and protons.
ABSTRACT To synthesize and compare available evidence considering the effectiveness of carbon-ion, proton and photon radiotherapy for head and neck cancer.
A systematic review and meta-analyses were performed to retrieve evidence on tumor control, survival and late treatment toxicity for carbon-ion, proton and the best available photon radiotherapy.
In total 86 observational studies (74 photon, 5 carbon-ion and 7 proton) and eight comparative in-silico studies were included. For mucosal malignant melanomas, 5-year survival was significantly higher after carbon-ion therapy compared to conventional photon therapy (44% versus 25%; P-value 0.007). Also, 5-year local control after proton therapy was significantly higher for paranasal and sinonasal cancer compared to intensity modulated photon therapy (88% versus 66%; P-value 0.035). No other statistically significant differences were observed. Although poorly reported, toxicity tended to be less frequent in carbon-ion and proton studies compared to photons. In-silico studies showed a lower dose to the organs at risk, independently of the tumor site.
For carbon-ion therapy, the increased survival in mucosal malignant melanomas might suggest an advantage in treating relatively radio-resistant tumors. Except for paranasal and sinonasal cancer, survival and tumor control for proton therapy were generally similar to the best available photon radiotherapy. In agreement with included in-silico studies, limited available clinical data indicates that toxicity tends to be lower for proton compared to photon radiotherapy. Since the overall quantity and quality of data regarding carbon-ion and proton therapy is poor, we recommend the construction of an international particle therapy register to facilitate definitive comparisons.
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ABSTRACT: Proton beam therapy (PBT) makes it possible to deliver a high concentration of radiation to a tumor using its Bragg peak, and it is simple to utilize as its radiobiological characteristics are identical to those of photon beams. PBT has now been used for half a century, and more than 60,000 patients worldwide are reported to have been treated with proton beams. The most significant change to PBT occurred in the 1990s, when the Loma Linda University Medical Center became the first hospital in the world to operate a medically dedicated proton therapy facility. Following its success, similar medically dedicated facilities have been constructed. Internationally, results have demonstrated the therapeutic superiority of PBT over alternative treatment options for several disease sites. Further advances in PBT are expected from both clinical and technological perspectives.International Journal of Clinical Oncology 03/2012; 17(2):79-84. · 1.41 Impact Factor
- Chinese Journal of Cancer Research 06/2013; 25(3):267-8. · 0.45 Impact Factor
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ABSTRACT: The use of particle ion beams in cancer radiotherapy has a long history. Today, beams of protons or heavy ions, predominantly carbon ions, can be accelerated to precisely calculated energies which can be accurately targeted to tumors. This particle therapy works by damaging the DNA of tissue cells, ultimately causing their death. Among the different types of DNA lesions, the formation of DNA double strand breaks is considered to be the most relevant of deleterious damages of ionizing radiation in cells. It is well-known that the extremely large localized energy deposition can lead to complex types of DNA double strand breaks. These effects can lead to cell death, mutations, genomic instability, or carcinogenesis. Complex double strand breaks can increase the probability of mis-rejoining by NHEJ. As a consequence differences in the repair kinetics following high and low LET irradiation qualities are attributed mainly to quantitative differences in their contributions of the fast and slow repair component. In general, there is a higher contribution of the slow component of DNA double strand repair after exposure to high LET radiation, which is thought to reflect the increased amount of complex DNA double strand breaks. These can be accurately measured by the γ-H2AX assay, because the number of phosphorylated H2AX foci correlates well with the number of double strand breaks induced by low or / and high LET radiation.Current Genomics 09/2012; 13(6):418-25. · 2.48 Impact Factor