Table 1 Risk of second fatal malignancy with IMRT compared to conventional or 3D-CRT

Followill 1997 [47]^¥

Out of field

Measured in phantom- previously published data

Whole body dose equivalent for neutrons and photons

6MV

0.6%§

1%

18MV

2.5%

4.5%

NCRP risk coefficients

25MV

4.5%

8.4%

Hall 2003 [2]

In field and out of field

Scanned volume: calculated from DVHs (TPS not stated)

LP

6MV

1%

1.75%

LE (with 2 gradients of dose fall off)

Scatter: measured in phantom- previously published

Kry 2005 [40]

Out of field

Measured in phantom- previously published data

Organ specific dose equivalents for photons and neutrons

6MV

NR

2.9%

10MV

NR

2.1%

15MV

NR

3.4%

NRCP risk co-efficients

18MV

1.7%

5.1%

Based on maximum MU to generate “conservative maximum risk estimate”

Schneider 2006 [41]

In field and out of field

Scanned volume: calculated from TPS (Eclipse 7.3.10)

Organ equivalent dose

Risk shown is increased risk relative to 15MV 3D-CRT

LE

6MV

15%(LE) 1%(LP)

Photon scatter and neutrons: measured in phantoms- previously published data

LP

15MV

20% (LE) 2% (LP)

18MV

60% (LE) 30% (LP)

Kry 2007 [50]

Out of field

Measured in phantom- previously published data

Organ specific dose equivalents for photons and neutrons

(Risk ratio relative to 18MV 3D-CRT and 90% CI in parentheses)

EPA risk co-efficients

6MV

with 1.9% (RR:1.4;1.1-1.8)

Based on average MU

10MV

1.5% (RR: 1.1; 0.9-1.3)

15MV

2.2% (RR: 1.6; 1.3-2.0)

18MV

3.6% (RR: 2.7; 2.1-3.2)

Schneider 2007 [49]

In field and out of field

Scanned volume: calculated from TPS (Eclipse 7.3.10)

Organ equivalent dose

Increased risk for 100Gy IMRT relative to 70Gy 15MV 3D-CRT

LNT

6MV

18.4% (LE), 15.0% (LP), 22.3% (LNT)

LE

15MV

25.3% (LE), 17.0% (LP), 14.1% (LNT)

Photon scatter and neutrons: measured in phantoms- previously published data

LP

Stathakis 2007 [45]

Primary and out of field photons

Calculated using Monte Carlo simulations (EGS4/MCSIM) using whole body CT scans

Whole body dose equivalent

6MV

2.40% (LNT)^**

3.55% (LNT)

NCRP risk coefficients

1.13%(LP)

2.65%(LP)

0.93%*

2.46%*

Neutron contribution not included-likely to increase risk by 4-10%

LNT

10MV

3.43% (LNT)

4.19%(LNT)

LP

1.72%(LP)

3.19% (LP)

Out-of-field component only

1.54%*

3.02%*

18MV

3.54% (LNT)

4.05% (LNT)

1.73%(LP)

3.07% (LP)

1.56%*

2.90% *

Ruben 2008 [42]

In field and out of field

Scanned volume: calculated from TPS Plato RTS v1.8 and Plato-ITP v2.5)

DVH analysis

18MV (3D-CRT)

1% (2.1%) (LP)

Data in parentheses shown for no correction for PCa patients with long term survival (i.e. no reduced weighting)

0.8% (1.5%)(LE)

Rest of body: measured in phantom Neutrons: measured in phantoms- previously published data

LP

6MV (IMRT)

0.8% (1.7%) (LP)

LE

0.6% (1.1%) (LE)

Stathakis 2009 [46]

In field and out of field

Calculated using Monte Carlo simulations (EGS4/MCSIM) using whole body CT scan

Whole body effective dose equivalent.

6MV

2.61%^**

3.39%

10MV

2.48%

3.09%

Neutron contribution not included

NRCP risk co-efficients

18MV

2.24%

2.84%

LNT

Bednarz 2010 [33]

Out of field

Calculated using Monte Carlo simulations (MCNPX) using computational phantom

BEIR VII co-efficients

18MV (3D-CRT: 4 field box + 6 field boost, anterior-posterior 4 field of box delivered using 6MV, rest of fields 18MV)

Risk of second tumour in:

Stomach: 0.03%

Colon: 0.3%

Oesophagus: 0.07%

Thyroid: 3.1X10^-4%

6MV IMRT

Risk of second tumour in:

Stomach: 0.04%

Colon: 0.4%

Oesophagus: 0.07%

Thyroid: 1.92X10^-4%

Patil 2010 [62]

In field

Scanned volume: calculated from TPS (Eclipse 7.3.10)

Organ equivalent dose

6MV

No comparator

Modal estimate per 10000 person years:

LP

Bladder: 0.1

Rectum: 3.42

Small intestine: 7.789

(Whole body: 129.95***)