ESTRO 36 Abstract Book

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S511 ESTRO 36
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Image-guided radiation therapy using MV imaging can be
incorporated into the treatment plan to give clinically
acceptable dose distributions. Dose to normal tissues is
increased, however, and depends on the imaging
technique, it is important to select the technique which
minimizes normal tissue dose while providing sufficient
image quality for patient setup.
Poster: Brachytherapy: Breast
PO-0922 Late toxicity and cosmetic outcome following
APBI using interstitial multicatheter HDR brachytherapy
T. Soror 1,2, G. Kovács2, N. Seibold 2, C. Melchert2, K.
Baumann 3, E. Wenzel 4, S. Stojanovic-Rundic5
1 National Cancer Institute, Radiation Oncology
Department, Cairo, Egypt
2 Interdisciplinary Brachytherapy Unit, University of
Luebeck/UKSH-CL- Germany, Lübeck, Germany
3 Clinic for Gynecology and Obstetrics, University of
Luebeck/UKSH-CL- Germany, Lübeck, Germany
4 Clinic for Plastic Surgery, University of Luebeck/UKSH-
CL- Germany, Lübeck, Germany
5 5Institute for Oncology and Radiology IORS, Radiation
Oncology Department, Belgrad, Serbia
Purpose or Objective
Accelerated partial breast irradiation (APBI) has became a
valid option in treating patients with early stage breast
cancer following breast conservation surgery (BCS). This
work reports on the late toxicity and the cosmetic
outcome following APBI using interstitial multicatheter
HDR intensity modulated brachytherapy (HDR-IMBT).
Material and Methods
Between 2006 and 2014, 114 patients received adjuvant
APBI using interstitial multicatheter HDR-IMBT. Late
toxicities were reported according to both the
RTOG/EORTC score and the LENT/SOMA score. Cosmetic
changes were documented by taking digital photographs
before the APBI and during each follow-up visit. For each
patient, we assessed two photographs, the first was taken
after surgery and before APBI (baseline image), and the
second at the last available follow-up visit. The cosmesis
was assessed through a multidisciplinary team using the
Harvard breast cosmesis scale. The clinical and the
dosimetric parameters were investigated for any potential
correlations with the cosmetic results.
Results
The median follow-up period was 3.5 years (range 0.6 –
8.5). Late skin/soft tissue toxicities at the last follow-up
visit are listed in Table1. Ten patients had grade-3 toxicity
(8.8%) and no patients showed grade-4 toxicity. The most
common toxicities were fibrosis (56.2% by LENT/SOMA
score, and 47.4% by RTOG/EORTC score) followed by pain
(42.1%).
The final cosmetic scores were 81.5% excellent/good and
18.5% fair/poor. Comparing both the baseline and the last
follow-up cosmetic scores, 59.6% of the patients had the
same score, 36% had a better final score, and 4.4% had a
worse final score. Patient age, tumor location, tumor size,
number of catheters, V100 (volume receiving 100% of the
prescription dose), V150 (volume receiving 150% of the
prescription dose), DNR (dose non-uniformity ratio), and
skin Dmax (maximum skin dose) were correlated with the
final cosmetic scores and with the change in cosmetic
scores between both photographs. Only lower DNR values
(0.3 vs 0.26; p=0.009) were significantly associated with
improved cosmetic outcome vs same/worse cosmetic
outcome.
Conclusion
APBI using interstitial multicatheter HDR-IMBT adjuvant to
BCS results in acceptable rates of late toxicity and
cosmetic outcome. Deterioration in the breast cosmetic
scores occurs in less than 5% of the patients. The final
breast cosmetic outcome seems to be mainly influenced
by the cosmetic result of the surgery. Lower DNR value is
significantly associated with better cosmetic outcome.
PO-0923 Does catheter entry-exit dosimetry correlate
with grade of skin marks after breast brachytherapy?
T. Wadasadawala1, R. Krishnamurthy1, U. Gayake1, R.
Phurailatpam1, S. Paul1, R. Sarin1
1Actrec-Tata Memorial Centre, Radiation Oncology, Navi
Mumbai, India
Purpose or Objective
Grade of post-implant skin marks after multi-cathetar
interstitial brachytherapy (MIB) is an important factor in
determining cosmesis. This study intends to establish the
correlation if any between catheter entry-exit (E-E)
dosimetry and grade of skin marks at the E-E sites.
Material and Methods
Visibility of the post implant E-E catheter marks was noted
plane-wise for 25 patients (173 planes) with minimum 18
months follow-up post implant. All patients were treated
with 34 Gy in 10 fractions, twice a day at minimum 6 hours
apart. These were graded as 'not visible', 'faint', 'clear' and
'prominent'. Dose received by the skin at the E-E sites was
calculated from the treated plans which were retrieved
from the Oncentra treatment planning system (Figure 1).
Dose maximum (Dmax) for each plane was determined
meticulously. Closest distance of each E-E point in each
plane from the respective first or last dwell position,
clinical target volume (CTV) and the reference isodose
(85%) was measured. Statistical analysis was done in IBM
SPSS version 21. Correlation between quality of implant
marks and dosimetric parameters was analyzed using
Spearman’s co-efficient (single tailed). Chi square test
was done between the quality of marks and plane Dmax as
well as closest distances each from CTV, prescription
isodose and first or last dwell position. ROC curve was used
to determine dose constraints.