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ESTRO 36
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EP-1158 Vmat radiation induced nausea/vomiting in
adjuvant breast cancer radiotherapy: dosimetrical
issues.
G. Lazzari
1
, A. Terlizzi
1
, B. Turi
1
, M.G. Leo
1
, D. Becci
1
, G.
Silvano
1
1
Azienda Ospedaliera SS. Annunziata Presidio Osped,
Radiology, Taranto, Italy
Purpose or Objective
Breast radiotherapy is associated with a minimal
emetogenic risk in MASCC/ESMO guidelines. Although the
emetogenic potential risk is estimated < 30%, VMAT
adjuvant radiotherapy may induce an unexpected acute
toxicity defined radiation induced nausea and vomiting
(RINV) as we observed in our experience. Aim of our report
is to find a correlation between dosimetrical factors and
RINV occurrence in our patients (pts).
Material and Methods
In our institutionfrom January 2013 to May 2016 106 breast
cancer pts were treated with adjuvant radiotherapy (RT)
in VMAT modality. Al pts had surgery ( conservative or
radical). Mean age was 54 years. Neoadjuvant or adjuvant
chemotherapy was given in 6 pts and 68 pts respectively
(62 pts had high risk emetogenic agents combination, 12
pts had CMF). Left side breasts were treated with in 95
pts, right breast RT occurred in 11 pts. CT planning
included all the chest from C6 to D12-L3 vertebrae. PTV
consisted of residual breast or chest wall and nodal sites.
According ICRU 83 , the prescribed dose was 50 Gy total
dose (2 Gy/25) to breast-chest wall and internal mammary
chain (10 pts). Supraclavicular nodes (36 pts) were treated
simultaneously , 1.92 Gy/25 fractions to 48 Gy total dose.
VMAT was planned on treatment planning system Oncentra
Masterplan® (collapsed cone algorithm) or Monaco®
(Monte Carlo photon algorithm) and consisted of dual arc
plan (170°/340° for left breast; 190°/20° for right breast)
and 6 MV photons beams. In all the pts we retrospectively
contoured on CT planning a volume containing the
anatomical structures of emetic vagal-simpatical
afferental pathways as the celiac plexus and
gastroesophageal junction (GEJCPs). This area was
identified as an organ at risk (OAR) for which the total
volume, Dmax, Dmean and D1cc were calculated.
Univariate analysis with χ
2
, t-test and Pearson covariance
were used for statistical analysis.
Results
On 106 pts, 68 (64%) patients complained acute RINV
according CTCAE v.3 criteria G1 nausea in 46 pts (43%), G2
nausea in 13 pts (12%), G1 vomiting in 8 pts (7 %) were
recorded. Symptoms occurred at 34 Gy delivered dose
(mean 30 Gy, range 20-34). In right side irradiated breasts
RINV occurred in 3 pts (27%), in left side RT in 65 pts (60%).
RINV was related to a Dmax >10 Gy on GEJCPs (p < 0.005).
G1 vomiting and G2 nausea were related to a Dmax > 17
Gy (p < 0.005) and to a Dmax > 15 Gy (p < 0.005)
respectively. Radiation breast side, age, systemic
therapy, nodal radiation and PTVs volume values were not
statistically significant for RINV.
Conclusion
RINV in breast radiation is not a common acute side effect.
VMAT in breast radiation is responsible for a low dose bath
to nearest structures as the GEJCPs and this may explain
RINV in our cases. A useful constraint as Dmax < 10 Gy on
GEJCPs like a serial structure may be considered in VMAT
breast planning to avoid RINV.
EP-1159 Hypofractionated adjuvant radiotherapy and
concomitant trastuzumab for breast cancer: 5-year
results
M. Pasetti
1
, A. Fodor
1
, C. Sini
2
, F. Zerbetto
1
, P. Mangili
2
,
P. Signorotto
2
, I. Dell'Oca
1
, C. Gumina
1
, M. Azizi
1
, A.M.
Deli
1
, P. Passoni
1
, N. Slim
1
, C.L. Deantoni
1
, B. Noris
Chiorda
1
, S. Foti
1
, A. Chiara
1
, G. Rossi
1
, C. Fiorino
2
, A.
Bolognesi
1
, N.G. Di Muzio
1
1
San Raffaele Scientific Institute, Department of
Radiotherapy, Milano, Italy
2
San Raffaele Scientific Institute, Medical Physics,
Milano, Italy
Purpose or Objective
To report 5-year outcomes and toxicity in early breast
cancer pts treated with whole breast hypofractionated
adjuvant radiotherapy(HRT) and concomitant trastuzumab
after breast conservation surgery(BCS).
Material and Methods
From February 2009 to October2011, 442 pts with breast
cancer pTis-T2 pN0-N1(up to 3 positive lymph nodes)
underwent forward planned intensity modulated HRT to a
TD=40 Gy/15 fr at out institution, and reached 5 year
median follow up; 31/442 pts presented c-erb B2
overexpression and were treated with HRT and
concomitant trastuzumab. Acute toxicity during HRT was
evaluated using the RTOG scale, while late side effects
were assessed using SOMA-LENT score.
Results
Patients’ median age was 60,5(28-75)years; tumor breast
side: 20 left and 11 right. Histology: DCI: 24 pts; DCI+DCIs:
6 pts; DCI+ LCIs:1 patient; apocrine carcinoma: 1 patient.
With a median follow-up of 63,8 (42,5-79,2) mts 3/31 pts
(9,7%) presented a local relapse, 2/31 pts ( 6,5%) a lymph
nodal relapse and 4/31 pts (12,9%) a distant relapse,
confirming the higher propensity for loco-regional and
distant relapse of c-erb B2 positive tumors. All pts were
alive at the last follow up. Acute toxicity was G0 in 7 pts
(22,6%), G1 in 20 pts(64,5%) and G2 in 4 pts(12,9%) with
no G3 toxicity. Late G1 edema and hyperpigmentation
persisting up to 18 mts after HRT was observed in 7 pts
(22,6%). Two persistent late toxicities were registered
only in pts treated with FEC chemotherapy before HRT:
one G2 fibrosis, starting 36 months after the end of HRT,
with breast volume of 1812 cc (cut-off observed in our
series: 866 cc), and one G3 teleangiectasy with breast
volume of 596 cc. Two cardiac toxicities were registered,
both in left sided breast cancers, one in a patient treated
with AC x3 cycles+TXT x 12 weeks +trastuzumab x 12 mts,
another in a patient treated with FECx5 cycles+
trastuzumab x 12 mts, which presented a mediastinal
relapse, treated with salvage chemotherapy. The same
patient presented BPCO exacerbations, again after the
salvage chemotherapy. While chemotherapy and breast
volume were important predictors for acute toxicity,
the
association of trastuzumab was not statistically
significant for both acute and late toxicity at the
multivariate analysis.
Conclusion
HRT after BCS demonstrated good outcomes and low
toxicity. The association of hypofractionated radiotherapy
with trastuzumab does not increase acute and late
toxicity.
EP-1160 T4s for T4 small Breast cancer: a new TNM
classification subgroup proposal
W.S. Zrafi
1
, S. Tebra
1
, H. Ouaz
1
, N. Bouaouina
1
1
Farhat Hached University Hospital, Radiation oncology
departement, Sousse, Tunisia
Purpose or Objective
T4 breast cancer are tumors of any size with direct
extension to the chest wall and, or the skin, including
inflammatory breast cancer. Non inflammatory T4 breast
cancer are a considerably heterogeneous group of tumors
with a subgroup of small-sized tumors.
Our aim is to evaluate the prognosis of small sized (under
3 cm) non inflammatory T4 breast cancer, comparing them
with larger T4 tumors and inflammatory breast cancer.