PMID- 28130055
OWN - NLM
STAT- MEDLINE
DCOM- 20180130
LR  - 20181202
IS  - 1724-191X (Electronic)
IS  - 1120-1797 (Linking)
VI  - 44
DP  - 2017 Dec
TI  - Optimal dose and fraction number in SBRT of lung tumours: A radiobiological 
      analysis.
PG  - 188-195
LID - S1120-1797(16)31119-X [pii]
LID - 10.1016/j.ejmp.2016.12.012 [doi]
AB  - The efficacy of Stereotactic Body Radiation Therapy (SBRT) in early-stage 
      non-small cell lung cancer for severely hypofractionated schedules is clinically 
      proven. Tumour control probability (TCP) modelling might further optimize 
      prescription dose and number of treatment fractions (n). To this end, we will 
      discuss the following controversial questions. Which is the most plausible 
      cell-survival model at doses per fraction (d) as high as 20Gy? Do clinical data 
      support a dose-response relationship with saturation over some threshold-dose? 
      Given the reduced re-oxygenation for severe hypofractionation, is the inclusion 
      of tumour hypoxia in TCP modelling relevant? Can iso-effective schedules be 
      derived by assuming a homogeneous tumour-cell population with alpha/beta approximately 10Gy, or should 
      distinct cell subpopulations, with different alpha/beta values, be taken into account? 
      Is there scope for patient-specific individualization of n? Despite the 
      difficulty of providing definite answers to the above questions, reasonable 
      suggestions for lung SBRT can be derived from the literature. The LQ model 
      appears to be the best-fitting model of cell-survival even at such large d, and 
      is therefore the preferred choice for TCP modelling. TCP increases with dose, 
      reaching saturation above 90% local control, but there is still uncertainty on 
      the threshold-dose. In silico simulations accounting for variations in tumour 
      oxygenation are consistent with an improved therapeutic ratio at 5-8 fractions 
      instead of the current 3-fraction reference schedules. Tumour hypoxia modelling 
      might also explain how alpha/beta changes with n, identifying the clonogen subpopulation 
      which determines tumour response. Finally, an optimal patient-specific n can be 
      derived from the planned lung dose distribution.
CI  - Copyright (c) 2016 Associazione Italiana di Fisica Medica. Published by Elsevier 
      Ltd. All rights reserved.
FAU - Ruggieri, Ruggero
AU  - Ruggieri R
AD  - Department of Radiation Oncology, Ospedale "Sacro Cuore - don Calabria", Via Don 
      A. Sempreboni 5, 37024 Negrar (VR), Italy. Electronic address: 
      ruggieri.ruggero@gmail.com.
FAU - Stavrev, Pavel
AU  - Stavrev P
AD  - Department of Radiation Oncology, Ospedale "Sacro Cuore - don Calabria", Via Don 
      A. Sempreboni 5, 37024 Negrar (VR), Italy.
FAU - Naccarato, Stefania
AU  - Naccarato S
AD  - Department of Radiation Oncology, Ospedale "Sacro Cuore - don Calabria", Via Don 
      A. Sempreboni 5, 37024 Negrar (VR), Italy.
FAU - Stavreva, Nadejda
AU  - Stavreva N
AD  - Department of Radiation Oncology, Ospedale "Sacro Cuore - don Calabria", Via Don 
      A. Sempreboni 5, 37024 Negrar (VR), Italy.
FAU - Alongi, Filippo
AU  - Alongi F
AD  - Department of Radiation Oncology, Ospedale "Sacro Cuore - don Calabria", Via Don 
      A. Sempreboni 5, 37024 Negrar (VR), Italy.
FAU - Nahum, Alan E
AU  - Nahum AE
AD  - Physics Department, University of Liverpool, UK.
LA  - eng
PT  - Journal Article
DEP - 20170124
PL  - Italy
TA  - Phys Med
JT  - Physica medica : PM : an international journal devoted to the applications of 
      physics to medicine and biology : official journal of the Italian Association of 
      Biomedical Physics (AIFB)
JID - 9302888
SB  - IM
MH  - Carcinoma, Non-Small-Cell Lung/pathology/*radiotherapy
MH  - *Dose Fractionation, Radiation
MH  - Humans
MH  - Lung Neoplasms/pathology/*radiotherapy
MH  - Neoplasm Staging
MH  - Radiobiology
MH  - Radiosurgery/*methods
OTO - NOTNLM
OT  - NSCLC
OT  - SBRT
OT  - TCP
EDAT- 2017/01/29 06:00
MHDA- 2018/01/31 06:00
CRDT- 2017/01/29 06:00
PHST- 2016/09/28 00:00 [received]
PHST- 2016/12/02 00:00 [revised]
PHST- 2016/12/14 00:00 [accepted]
PHST- 2017/01/29 06:00 [pubmed]
PHST- 2018/01/31 06:00 [medline]
PHST- 2017/01/29 06:00 [entrez]
AID - S1120-1797(16)31119-X [pii]
AID - 10.1016/j.ejmp.2016.12.012 [doi]
PST - ppublish
SO  - Phys Med. 2017 Dec;44:188-195. doi: 10.1016/j.ejmp.2016.12.012. Epub 2017 Jan 24.