Systematic review and meta-analysis of radiotherapy in various head and neck cancers: comparing photons, carbon-ions and protons.
OBJECTIVE
To synthesize and compare available evidence considering the effectiveness of carbon-ion, proton and photon radiotherapy for head and neck cancer.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Ramaekers
Bram L T
BL
Department of Radiation Oncology (MAASTRO), GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands. bram.ramaekers@maastro.nl
Pijls-Johannesma
Madelon
M
Joore
Manuela A
MA
van den Ende
Piet
P
Langendijk
Johannes A
JA
Lambin
Philippe
P
Kessels
Alfons G H
AG
Grutters
Janneke P C
JP
D002244:Carbon / Q000627:therapeutic use*; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D007477:Ions / Q000627:therapeutic use; D017785:Photons / Q000627:therapeutic use*; D061766:Proton Therapy; D011878:Radiotherapy / Q000379:methods*
D007477:Ions; D002244:Carbon