ESTRO 36 Abstract Book

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S676 ESTRO 36 2017
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Target volume coverage and homogeneity were
comparable between the different planning techniques.
We compared multiple dose volume parameters to OAR
including V40 Gy and V50 Gy to the bowel cavity, V45 Gy
to the bladder, mean dose to femoral heads using IMRT, 2
arc VMAT and 3 arc VMAT techniques and found no
significant differences in any parameter. Both 3- and 4-
field proton treatment plans demonstrated significant
sparing on V40 Gy to the bowel cavity: median volume
using 2 Arc VMAT was 667 cc, 3- and 4-field proton therapy
522 cc and 535 cc respectively. V45 Gy to the bladder was
also considerably lower using protons: 2 arc VMAT 49,3%
vs. 23,4% and 28,5% using 3- and 4-field proton therapy.
Mean dose to femoral heads was significantly lower with
proton therapy while V40 Gy and V30 Gy to the sacral bone
were comparable.
Conclusion
We found dosimetric equality on the selected parameters
for OAR when comparing 2 arc VMAT with fixed field IMRT
and 3 arc VMAT, and no differences between 2 and 3 arc
VMAT either. VMAT reduces overall treatment time and is
a feasible option for standard treatment planning in SCCA.
In four patients with high V40 Gy to the bowel proton
treatment plans proved superior in V40 Gy to the bowel,
V45 Gy to the bladder, and mean dose to femoral heads
with the potential to reduce subsequent toxicity. Data on
acute toxicity will be presented at the meeting.
EP-1270 Clinical outcome of non-metastatic rectal
cancer patients with extremely high CEA level
S.H. YOUN1, D.Y. KIM1, T.H. KIM 1, S.Y. KIM2, J.H. BAEK2,
Y.J. CHA2, H.J. CHANG2, M.J. KIM 2, S.C. PARK 2, J.H. OH2
1 National Cancer Center, Proton Therapy Center,
Goyang-si-, Korea Republic of
2 National Cancer Center, Center for Colorectal Cancer,
Goyang-si-, Korea Republic of
Purpose or Objective
To investigate clinical outcome of non-metastatic rectal
cancer patients with extremely high pretreatment serum
CEA level after radical surgery following preoperative
chemoradiotherapy
Material and Methods
A total of 959 patients with clinical stage II-III rectal
cancer who underwent preoperative chemoradiotherapy
followed by radical surgery between October 2001 and
July 2011 were retrospectively analyzed. There were 332
patients with elevated pretreatment serum CEA level (>
5ng/ml) and among them, we defined 23 patients with CEA
level of > 50 ng/ml as an extremely high pretreatment CEA
group. Overall survival rate, relapse-free survival rate,
locoregional recurrence-free survival rate and distant
metastasis-free survival rate were compared between
pretreatment CEA levels of 5-50 ng/ml and > 50 ng/ml.
Results
Median follow-up duration was 69 months (range, 3-165).
The five-year survival rate were 80.5% and 73.4%, and the
10-year survival rate were 64.5% and 73.4% in patients
with pretreatment serum CEA level of 5-50 ng/ml and > 50
ng/ml, respectively ( p = 0.672). The extremely high CEA
group (> 50 ng/ml) had significantly lower relapse-free
survival rate (RFS) at 5-year and 10-year than patients
with CEA level of 5-50 ng/ml (5-year RFS 70.6% versus.
52.2%, and 10-year RFS 62.1% versus. 52.2%, p = 0.048,
respectively). Also, patients with extremely high CEA (>
50ng/ml) had trend to lower distant metastasis-free
survival rate (DMFS) (5-year DMFS 72.0% versus. 55.9%, and
10-year DMFS 67.4% versus. 55.9%, p = 0.087,
respectively), and there were no differences in
locoregional recurrence-free survival rate (LRRFS) (5-year
LRRFS 89.3% versus. 81.8%, 10-year LRRFS 82.8% versus.
81.8%, p = 0.355).
Conclusion
This study showed that non-metastatic rectal cancer
patients with extremely high pretreatment serum CEA
level (> 50 ng/ml) had higher risk of relapse with trend of
increasing distant metastasis.
EP-1271 Is 3D-CRT still a valid option in radical
radiochemotherapy of anal carcinoma in the era of
IMRT?
S. Shakir 1, A. Garant2, S. Alshehri2, D. Slobodan3, T.
Alcindor4, T. Vuong1
1Jewish General Hospital, Radiation Oncology, Montreal,
Canada
2McGIll University Health Center, Radiation Oncology,
Montreal, Canada
3Jewish General Hospital, Medical physics, Montreal,
Canada
4McGIll University Health Center, Medical oncology,
Montreal, Canada
Purpose or Objective
Intensity Modulated Radiation Therapy (IMRT) is well
accepted in our institution as standard radiation technique
for patients with anal canal cancer. We are reporting
treatment related toxicity profiles recorded during
treatment with 3D conformal radiation (3D-CRT) versus
IMRT with radical concomitant radiochemotherapy at
McGill University Health Center.
Material and Methods
This is a retrospective study of all patients’ charts
diagnosed with squamous cell carcinoma of anal cancer
from January 2002 to May 2009. The standard treatment
was radical radiation with 2 cycles of chemotherapy using
5-Fluorouracil (1000mg/ m2 daily for 4 days in a 24 hours
continuous perfusion) and Mitomycin-C (at 10 mg / m2).
Radiation doses were 50.4 Gy, 54 Gy and 60 Gy in 28, 30,
33 fractions to macroscopic disease for T1, T2/T3, and T4
tumors respectively and 30 Gy in 15 fractions to
microscopic nodal disease at risks. Demographic data,
treatment modality, different acute toxicities and
tolerance as well as outcomes were compared between
patients treated with 3D-CRT using conformal diamond
diagonal opposing fields [1], and those treated with IMRT.
Results
From January 2002 to May 2009, 90 patients (3D-CRT: 40,
IMRT: 50) treated with radical intent were included in this
study. The median age for the entire cohort was 57 years.
Male to female ratio was 0.61. Fifty-four percent (n=41)
of patients had greater than stage II disease (table 1-A).
Acute toxicities were collected prospectively with weekly
blood tests, intra treatment weekly evaluation for bowel
frequency, skin-reaction and hospital admission for
treatment related toxicity. Toxicity grading was based on
the national cancer Institute common toxicity criteria
version 2.0. The rates of ≥ grade 2 skin, hematological and
gastrointestinal toxicities for 3D-CRT group were 65%, 45%
and 25% respectively; whereas for IMRT group; 58%, 48%
and 20% respectively with corresponding p values of 0.522,
0.834 and 0.617 respectively. Treatment interruption rate
was significantly higher (p value: 0.018) with 5% vs 24%
rate among patients treated by 3D-CRT vs IMRT, despite a
non-significant difference for higher grade 3
hematological rate of 20% versus 28% for 3D-CRT and IMRT
groups, respectively, (p = 0.46), (table 1-B).
Conclusion
Acute toxicity profiles did not differ significantly between
the two radiotherapy techniques, but treatment
interruption was significantly higher in IMRT group with a
trend of higher grade 3 hematotoxicity. Thus, 3D-CRT
diamond fields remain a valid option for patients with anal
canal cancer. Since May 2009, IMRT has become our
standard treatment and we are now looking at its impact
on local control in our patient population.