Risk of radiation-induced second malignant neoplasms from photon and proton radiotherapy in paediatric abdominal neuroblastoma

Abstract

Background and Purpose: State-of-the-art radiotherapy modalities have the potential of reducing late effects of treatment in childhood cancer survivors. Our aim was to investigate the carcinogenic risk associated with 3D conformal (photon) radiation (3D-CRT), intensity modulated arc therapy (IMAT) and pencil beam scanning proton therapy (PBS-PT) in the treatment of paediatric abdominal neuroblastoma. Materials and Methods: The risk of radiation-induced second malignant neoplasm (SMN) was estimated using the concept of organ equivalent dose (OED) for eleven organs (lungs, rectum, colon, stomach, small intestine, liver, bladder, skin, central nervous system (CNS), bone, and soft tissues). The risk ratio (RR) between radiotherapy modalities and lifetime absolute risks (LAR) were reported for twenty abdominal neuroblastoma patients (median, 4y; range, 1-9y) historically treated with 3D-CRT that were also retrospectively replanned for IMAT and PBS-PT. Results: The risk of SMN due to primary radiation was reduced in PBS-PT against 3D-CRT and IMAT for most patients and organs. The RR across all organs ranged from 0.38 ± 0.22 (bladder) to 0.98 ± 0.04 (CNS) between PBS-PT and IMAT, and 0.12 ± 0.06 (rectum and bladder) to 1.06 ± 0.43 (bone) between PBS-PT and 3D-CRT. The LAR for most organs was within 0.01-1% (except the colon) with a cumulative risk of 21 ± 13%, 35 ± 14% and 35 ± 16% for PBS-PT, IMAT and 3D-CRT, respectively. Conclusions: PBS-PT was associated with the lowest risk of radiation-induced SMN compared to IMAT and 3D-CRT in abdominal neuroblastoma treatment. Other clinical endpoints and plan robustness should also be considered for optimal plan selection.

Automatic Radiobiological Comparison of Radiation Therapy Plans: An Application to Gastric Cancer

“…The corresponding dimensions for the female phantom were 1627 mm and 66 kg. The XCAT phantoms have already been used for treatment planning and dosimetric purposes in radiation therapy [ 10 , 11 , 12 ].…”

Proton‐to‐photon comparative treatment planning guidelines for the Australian context

“…If target volume coverage is comparable between PBT and photon treatment plans and there is negligible difference between the probabilities of late effects, differences in integral dose should be considered as a means to reduce the likelihood of second cancer induction. Use of second cancer induction models may be useful to estimate the relative risk associated with proton and photon dose distributions 31,32 ; however, the significant uncertainty inherent in such models should also be noted in the evaluation report.…”