Targeted Intraoperative Radiotherapy Tumour Bed Boost: Our experience
Victoria Navarro Aznar,
Spain
PO-1203
Abstract
Targeted Intraoperative Radiotherapy Tumour Bed Boost: Our experience
Authors: Victoria Navarro Aznar1, Arantxa Campos Bonel2, Cecilia EscuÃn Troncho2, Anabela Miranda3, MarÃa Cerrolaza Pascual2, Alberto Lanuza Carnicer2, Sonia Flamarique Andueza2, Patricia Rubio4, Verónica Alba Villalba5, Maria Carmen Casamayor Franco6, Reyes Ibáñez Carreras2
1Hospital Universitario Miguel Servet, Radiation Oncology , Zaragoza, Spain; 2Hospital Universitario Miguel Servet, Radiation Oncology, Zaragoza, Spain; 3SOLCA Matriz Guayaquil , Radiation Oncology, Guayaquil, Ecuador; 4Hospital Universitario Miguel Servet, Gynecology, Zaragoza, Spain; 5Hospital Universitario Miguel Servet, Radiophysics, Zaragoza, Spain; 6Hospital Universitario Miguel Servet, General Surgery, Zaragoza, Spain
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Purpose or Objective
Intraoperative radiotherapy (IORT) can
be used as a technique of tumour bed overimpression in patients with molecular
profile early stage high-risk breast cancer (Her2+ and Triple Negative) in whom
initial surgical treatment is performed. This technique is considered an option
for local treatment until completion of external radiotherapy, once systemic
therapy has been completed, with an impact on local control of the disease. Our
objective is to analyse local control and toxicity.
Material and Methods
From a total of 707 patients treated
between May 2015 and May 2021 with IORT in our community, 31 patients received
initial treatment as boost, delivering a single dose of 20Gy using 50 kV X-rays.
Subsequently, this was completed with hypofractionated hologlandular external
beam radiotherapy. We analysed demographic, surgical, radiotherapeutic and
local control data.
Results
The mean age was 67 years. All tumours
were infiltrating ductal carcinoma with a mean size of 14.53mm. 77.42% (n=24) were Triple Negative, 19.35%
(n=6) Luminal B-HER2+ and 3.22% (n=1) pure Her2.
The mean IORT administration time was 9.8
minutes. Adjuvant glandular radiotherapy was performed with a median interval
of 6.6 months during which systemic treatment was given. The adjuvant
fractionation schedules used were 40.05Gy in 15 sessions in 62.5% and 26Gy in 5
sessions in 37.5%.
At a median follow-up of 25 months,
there was no acute or chronic toxicity > G2, and no local or distant
relapses have been observed.
Conclusion
The application of IORT as an
overimpression of the tumour bed in patients with early stage breast cancer and
poor prognostic subtypes allows to secure the bed until other adjuvant
therapies are given. A comparison between boost administration with IORT vs.
integrated with external beam radiotherapy in these patients would remain to be
done in the future.