728 / 1096
S712
ESTRO 36
_______________________________________________________________________________________________
The NTCP model used previously validated dosimetric
parameters for late rectal bleeding: mean dose (Gy) and
V75 (%) as dosimetric predictors for late rectal bleeding.
It also included clinical parameters such as haemorrhoids
or use of hormonal therapy. The cost-effectiveness was
analyzed using an earlier published Markov model. The
incremental net monetary benefits (iNMB) was calculated
(assuming a willingness to pay of €80.000/QALY).
Results
The NTCP for the patients with a RBI and the virtual IRS
were 4.1% [range: 3.6-5.0%], and 4.0% [range: 3.4%-5.3%]
respectively. For the patients with a SPA the mean NTCP
was 4.6% [range: 3.7%-6.1%] while this was 4.4% [range:
3.8%-4.7%] for the virtual IRS (Table 1).
The mean iNMB of the RBI was -€ 1062 [range: -€ 1,974-€
658]. For the virtual IRS in these patients this was -€ 1042
[range: -€ 1,526.8-€ 400]. The mean iNMB of the SPA was
-€ 605 [range: -€ 2,383-€ 427]. For the virtual IRS this was
-€ 473 [range: -€ 1,405-€ 528] (Figure 1).
The virtual IRS had a 100% classification accuracy for this
study, i.e. when the iNMB of the real IRS was negative, so
was the iNMB of the virtual spacer, and visa-
versa.
Conclusion
Individual patient assessment for implantation of an IRS
will increase cost-effective ness of an IRS. The virtual IRS
approach in combination with a toxicity prediction model
and a cost-effectiveness analyses can serve as a decision
support tool for the implantation of either a SPA or a RBI.
EP-1328 Long term patients clinical outcome after
adjuvant postprostatectomy Radiation Therapy
P. Pietro Gabriele (Italy), A. Angelo Maggio, E. Elena
Delmastro, E. Elisabetta Garibaldi, S. Sara Bresciani, M.
Marco Gatti, A. Andrea Galla, M. Michele Stasi, D.
Domenico Gabriele
1
IRCCS-FPO candiolo cancer center, radiotherapy,
CANDIOLO Turin, Italy
2
IRCCS-FPO candiolo cancer center, medical physics,
candiolo /urin, Italy
3
IRCCS-FPO candiolo cancer center, radiotherapy
department, candiolo Turin, Italy
4
SASSARI university, radiotherapy department, SASSARI,
Italy
Purpose or Objective
To study the outcome of patients (pts) treated for prostate
cancer with postoperative radiotherapy (RT) after radical
surgery
Material and Methods
From October 1999 and December 2015, 279 patients (age
42-77ys median 66) operated for prostate cancer were
treated in our Institution with conformal radiotherapy (3D
or IMRT). Median preoperative PSA was 9 (range: 0.5-104),
median pathologic GS 7 (range: 4-10) and number of pts
with ct1, cT2, cT3 and cT4 were 1, 60, 207 and 11,
respectively. Lymph node invasion was presented in 34
patients; the number of nodes removed was 7 (0-38); the
number of patients with positive margins were 195 (69 %);
post-surgery PSA was 0.073 ng/mL (range: 0-6.22).
Radiation therapy was performed with Linac from 1999 to
2009 by 3DCRT and with Tomotherapy from 2010 by IMRT-
IGRT. Radiation dose were, 70.2 Gy (range 61.6-75.6 Gy)
to the prostate bed and 46.8 Gy (45-50.4) to the pelvis,
1.8Gy per fraction. The pelvis was irradiated in 65 patients
(24 %). 64 patients (23%) were treated during RT
with hormone therapy and 49 (18%) followed the
treatment after RT.
Results
With a median FU of 73.4 (range: 4-212) months from the
end of RT the 10 years prostate Cancer Specific Survival
was 88%; the Clinical Relapse Free Survival was 72% and
Biochemical Relapse Free Survival 60%. Cox univariate and
multivariate (MVA) analysis were performed. In MVA, the
pathologic Gleason Score (p<0.0001; HR>1.49) and last
follow-up PSA (p<0.001;HR>1.0006) were significantly
predictors for prostate Cancer Specific Survival, Clinical
Relapse Free Survival and Biochemical Relapse Free
Survival.
Conclusion
In this, based on a large database, it was found that the
Gleason score and the PSA measured at last low-up were
significantly independent prognostic factors of survival for
patients treated with postprostatectomy adjuvant RT.
Acknowledgments:
This work was supported by “5 per
Mille 2009 Ministero Salute-FPRCOnlus”.
EP-1329 IG-SBRT for localized prostate cancer: clinical
results and late toxicity of a phase-II study
A. Magli
1
, E. Moretti
2
, A. Tullio
3
, C. Foti
2
, M. Crespi
2
, M.
Urpis
1
, A. Prisco
1
, M.R. Malisan
4
1
ASUIUD, Radiation Oncology, Udine, Italy
2
ASUIUD, Medical Physics, Udine, Italy
3
Hygiene and Clinical Epidemiology Institute - University
of Udine, Department of Medical and Biological Sciences,
Udine, Italy
4
ICTP, Master of Advanced Studies in Medical Physics,
Trieste, Italy
Purpose or Objective
To evaluate the clinical outcome and late toxicity of a
phase II study dealing with SBRT with a total dose of 42 Gy
in 7 fractions, in patients with localized prostate cancer
at low/intermediate risk (according to NCCN score) and at
risk of pelvic lymph node involvement inferior to 17% as
evaluated by the Roach formula.
Material and Methods
This study was based on a prospective analysis of 42
patients enrolled between May 2013 and November 2014.
For planning, the GTV included the prostate with the 1/3
proximal seminal vesicles without margin; a margin of 5
mm in all directions around the GTV was applied to define
the PTV. All patients were treated with IG-SBRT, utilizing
VMAT technique with a 2 full arcs arrangement and
photons with beam energy of 6 MV, according to pre-