Physica Medica: European Journal of Medical Physics - Volume 32 - Supplement 1

A.48

POTENTIAL RADIATION-INDUCED MESOTHELIOMA AMONGST LONG-

TERM SOLID CANCER SURVIVORS

A. Farioli

a ,

G. Compagnone

, b ,

M. Ottone

a ,

A.L. Angelin

i b ,

F. Romani

b ,

C. Parmeggiani

b ,

G. Frezza

c ,

A.G. Morgant

i c ,

F.S. Violante

a .

UO Medicina

del Lavoro, Azienda Ospedaliero – Universitaria di Bologna, Bologna, Italy;

Fisica Sanitaria, Azienda Ospedaliero – Universitaria di Bologna, Bologna, Italy;

UO Radioterapia, Azienda Ospedaliero – Universitaria di Bologna, Bologna,

Italy

Introduction:

Malignant mesothelioma is a rare cancer that usually origi-

nates from the pleural and peritoneal lining cells. Evidence on the association

between external beam radiotherapy (EBRT) and pleural and peritoneal me-

sotheliomas is still controversial: thus the purpose of this study was to

analyse that relationship amongst long-term (

5 years) solid cancer survivors.

Materials and methods:

Data from the United States Surveillance, Epide-

miology and End Results (SEER) programme from 1973 to 2012 were

analysed. Cox proportional hazards regression survival models, adjusted

by age, gender, race and relative risk of primary mesothelioma in the county

of residence, were fitted for estimating cause-specific hazard ratios (HR)

with reference to non-irradiated patients. Latency was calculated by re-

ferring to the year of primary cancer diagnosis. Figures on cancer, and

individual records, were obtained with SEER*Stat software 8.2.1. The main

statistical analysis was carried out using Stata 12.1 SE (Stata Corporation)

software package.

Results:

A total of 913,873 patients were studied and 300 mesotheliomas

(264 pleural, 32 peritoneal, 4 others) were observed. The exposure was clas-

sified on the basis of presumed doses received by the mesothelium,

depending on the location of the primary cancer: direct and scattered ex-

posures were defined as the primary cancer was located within/next (

3 cm)

or far (

3 cm) from the pleura/peritoneum, respectively. The EBRT in-

creased the risk of mesothelioma (any site, fully adjusted HR

1.36, 95%

1.05–1.76). Only direct peritoneal irradiation was associated with peri-

toneal mesothelioma (age- and sex-adjusted HR

2.13, 95% CI

0.96–

4.74), particularly for latencies

10 years (HR

3.19, 95% CI

1.11–9.18).

Conclusions:

The clinical impact of secondary mesothelioma after EBRT

for a primary solid cancer is limited.

http://dx.doi.org/10.1016/j.ejmp.2016.01.052

A.49

CELL IRRADIATION TO INVESTIGATE MARKERS OF IONIZING RADIATION-

INDUCED DNA DAMAGE

G. Compagnone

* , a ,

A. Lorenzini

b ,

F. Romani

a ,

E. Croco

c ,

A.L. Angelini

a ,

M. Di Donna

a ,

S. Cammelli

d ,

A.G. Morganti

d .

UO Fisica Sanitaria, Azienda

Ospedaliero – Universitaria di Bologna, Bologna, Italy;

Dip. Scienze Biomediche

e Neuromotorie, Università di Bologna, Bologna, Italy;

Dip. Scienze per la

Qualità della vita, Università di Bologna, Bologna, Italy;

UO Radioterapia,

Azienda Ospedaliero – Universitaria di Bologna, Bologna, Italy

Introduction:

The detailed knowledge of mechanisms of DNA lesion repair

is crucial in many areas, from cancer cell killing by radiotherapy to proper

immune system development to cell aging, just to quote a few examples.

The purpose of this work was to study both qualitatively and quantita-

tively some novel DNA damage markers.

Materials and methods:

Cells were seeded on 160-μm-thick coverslips and

then irradiated with a calibrated Therapax 300 roentgentherapy unit at

60 kV, 25 mA and 1.65 mm Al of added filtration with 2 different geom-

etries, at source-to-surface distances of 30 cm (Modality A) and 50 cm

(Modality B). The same standard 10 Gy dose was delivered in the differ-

ent geometries and required exposure times of 7.5 and 21 min in Modalities

A and B, respectively. In Modality B the irradiation field was larger

(20 cm

20 cm) and a 12 multi-well cell culture cluster was used. Doses

lower than 10 Gy were also used in order to obtain a dose–response rela-

tionship with the investigated markers.

In parallel with radiation treatment, two chemotherapeutic agents were

also used: Etoposide and Neocarzinostatin.

Different markers of DNA damage were employed. A first set was repre-

sented by proteins directly involved in the DNA repair pathways: they are

either accumulated or activated in response to DNA damage and can be

identified by immunofluorescence. Another set was represented by the

more traditional comet and micronuclei assays, two tests that measure

directly, although at different levels, the physical damage endured by

DNA.

Results:

Our data show that at high DNA damage load cells with different

sensitivity respond in an indistinguishable way. At lower DNA damage load,

instead, it is possible to differentiate between cells with different damage

sensitivity.

Conclusions:

These new immunofluorescence-based markers could be

useful for studying by means of ionizing radiations the different sensitiv-

ity of cells to DNA damage.

http://dx.doi.org/10.1016/j.ejmp.2016.01.053

A.50

TOTAL BODY IRRADIATION: A TRADITIONAL TECHNIQUE RECONSIDERED

IN THE LIGHT OF TREATMENT PLANNING SYSTEM

A. Compagnucci

* , a ,

F. Fabbrizzi

b ,

C. Arilli

a ,

M. Casati

a ,

L. Marrazzo

a ,

C. Talamonti

a , b ,

S. Calus

i b ,

G. Simontacch

i a ,

S. Pallott

a a , b .

Azienda Ospedaliero

Universitaria Firenze, Firenze, Italy;

Universita’ degli Studi di Firenze, Firenze,

Italy

Introduction:

The aim of this study is to verify the possibility of plan-

ning TBI treatments with the treatment planning system (TPS).

Materials and methods:

In our hospital, AP-PA technique with 25MVRX

photon beam from Elekta Precise Linac is used. Total prescribed dose is 12 Gy.

With the patient lying in supine position, it is possible to plan the treat-

ment with the TPS. Beam calibration is performed with a Farmer ionization

chamber in a water phantom at 10 cm depth and SDD 4 m. Since both treat-

ment and beam calibration are performed in conditions very different with

respect to those for which the TPS is commissioned, the agreement between

measured and calculated values of TPR20/10 and absolute dose in TBI cal-

ibration conditions is investigated. Furthermore doses, measured on a Rando

phantom with an in-vivo dosimetry setup, are compared with the values

calculated by the TPS. For the in-vivo dosimetry, semi-conductor diodes

PTW-T60010HP (3 cm inherent build up), VIVODOS PTW-T10018 elec-

trometer and VIVOSOFT software are used. The influence of the dose rate,

distance and presence of immobilization cushion over the calibration of

the diodes is evaluated. Rando is irradiated with entrance and exit diodes

positioned at different superior–inferior levels of the body and the dose

at midline is evaluated. Entrance (Din) and exit (Dex) in-vivo measure-

ments are compared with the dose calculated by the TPS Pinnacle at 3 cm

of depth in the phantom, while the mean dose (Din

Dex)/2 is compared

with the dose calculated at midline.

Results:

The measured TPR and the absolute dose in calibration

conditions agree with TPS values within 1.5%. The dose rate and the

distance influence the diode calibration for 1%, while the presence of

cushion is irrelevant. For the in-vivo dosimetry the agreement between

the dose calculated by TPS and the dose measured by the diodes is

within 3%.

Conclusion:

The treatment planning system can be used in order to eval-

uate the dose distribution for a patient undergoing TBI irradiation.

http://dx.doi.org/10.1016/j.ejmp.2016.01.054

A.51

COMBINED RT AND EPIDERMAL GROWTH FACTOR RECEPTOR INHIBITOR

MONOCLONAL ANTIBODY-MOAB-EGFR TREATMENT OF HEAD AND NECK

CANCER (HNC): RADIOBIOLOGICAL MODEL FOR FAMOSO

M. Cremonesi

, a ,

D. Alterio

a ,

C. Garibaldi

a ,

A.M. Ferrari

a ,

F. Botta

a ,

M. Ferrari

a ,

S. Vigorito

a ,

E. Rond

i a ,

F. Cattani

a ,

M. Cossu Rocc

a a ,

L. Strigari

b ,

P. Pedicini

c ,

B.A. Jereczek-Fosa

a , d ,

R. Orecchia

a , d , e .

Istituto Europeo di

Oncologia, Milano, Italy;

Istituto Nazionale dei Tumori Regina Elena, Roma,

Italy;

R.C.C.S.-C.R.O.B., Rionero in Vulture, Italy;

Università degli Studi, Milano,

Italy;

CNAO Centro Nazionale di Adroterapia Oncologica, Pavia, Italy

Objective:

Administration of MoAbEGFr inhibitor during RT of HNC has

shown radiosensitizing effect as compared to RT alone. MoAb-EGFr con-

centration and radiosensitizing effect vary day by day after every week of

administration. A radiobiological (RB) model accounting for this variation

was adopted in the clinical protocol FAMOSO “Frazionamento Accelerato

MOdulato in SIB-IMRT dei tumori testa-collO” in order to optimize daily

e15

Abstracts/Physica Medica 32 (2016) e1–e70