The risk of developing a second cancer after receiving craniospinal proton irradiation.
The purpose of this work was to compare the risk of developing a second cancer after craniospinal irradiation using photon versus proton radiotherapy by means of simulation studies designed to account for the effects of neutron exposures. Craniospinal irradiation of a male phantom was calculated for passively-scattered and scanned-beam proton treatment units. Organ doses were estimated from treatment plans; for the proton treatments, the amount of stray radiation was calculated separately using the Monte Carlo method. The organ doses were converted to risk of cancer incidence using a standard formalism developed for radiation protection purposes. The total lifetime risk of second cancer due exclusively to stray radiation was 1.5% for the passively scattered treatment versus 0.8% for the scanned proton beam treatment. Taking into account the therapeutic and stray radiation fields, the risk of second cancer from intensity-modulated radiation therapy and conventional radiotherapy photon treatments were 7 and 12 times higher than the risk associated with scanned-beam proton therapy, respectively, and 6 and 11 times higher than with passively scattered proton therapy, respectively. Simulations revealed that both passively scattered and scanned-beam proton therapies confer significantly lower risks of second cancers than 6 MV conventional and intensity-modulated photon therapies.
Newhauser
Wayne D
WD
Department of Radiation Physics, The University of Texas M D Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX, 77030, USA. wnewhaus@mdanderson.org
Fontenot
Jonas D
JD
Mahajan
Anita
A
Kornguth
David
D
Stovall
Marilyn
M
Zheng
Yuanshui
Y
Taddei
Phillip J
PJ
Mirkovic
Dragan
D
Mohan
Radhe
R
Cox
James D
JD
Woo
Shiao
S
D004781:Environmental Exposure; D006801:Humans; D008093:Literature, Modern; D008280:Magnetics; D008297:Male; D009010:Monte Carlo Method; D009381:Neoplasms, Radiation-Induced / Q000209:etiology* / Q000473:pathology*; D009502:Neutrons / Q000009:adverse effects; D061766:Proton Therapy; D011874:Radiometry; D011878:Radiotherapy / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects; D012306:Risk; D012542:Scattering, Radiation; D012886:Skull / Q000528:radiation effects*; D013131:Spine / Q000528:radiation effects*; D011522:Protons
D011522:Protons