Med Bull Sisli Etfal Hosp. 2021; 55(1): 81-85 | DOI: 10.14744/SEMB.2020.25986

Effective of Pre-operative 2-Deoxy-2-[fluorine-18] fluoro-d-glucose/Positron Emission Tomography/Computed Tomography in the Determination of Boost Volume in Adjuvant Radiotherapy after Breast-conserving Surgery

Berrin Inanc¹, Kubilay Inanc², Begum Okten¹, Ozlem Mermut^1
1Department of Radiation Oncology, University of Health Sciences, Istanbul Training and Research Hospital, Istanbul, Turkey
²Department of Radiation Oncology, University of Health Sciences Turkey, Sisli Hamidiye Etfal Teaching and Research Hospital, Istanbul, Turkey

Objectives: Determining boost volume (BV) during breast radiotherapy can be challenging at times. Therefore, surgical clips are now being widely used. At times, when surgical clips are inadequate in determining the BV, other additional imaging methods are required. In the present study, we aimed to demonstrate that pre-operative positron emission tomography/computed tomography (PET-CT) can be used to determine the BV after a breast-conversing surgery.
Methods: We selected thirty patients who underwent breast-conserving surgery with surgical clips and had preoperative Fluorine-18-Fluorodeoxyglucose PET (18 FDG PET/CT). The BV in planning tomography (CT) and primary tumor volume (TV) in pre-operative F-18 FDG PET/CT was contoured by a radiation oncologist. These two volumes were superposed using rigid image fusion. In every patient, two BVs were measured. The mean shift between the two volumes by the calculation of the center of mass and percentage of the PET-CT TV (PET-CT TV) in planning the BV (planning target volume [PTV]-BV) was calculated.
Results: The median age was 52 years (range 25–72 years). The pre-operative PET-CT TV median was 8.89 cm3 (range 1.00–64.30 cm3). The median PTV-BV was 62.92 cm3 (12.57–123.07 cm3). The median shifts between the center of volumes were 1.76 cm (range 0.90–3.50) in X(coronal), 1.73 cm (range 0.60–3.60) in the Y(axial), and 1.20 cm (0.40–2.80) in the Z(sagittal) directions, respectively. The shifts in these three planes were determined to be statistically significant (p<0.001). The percent volume of PET-CT TV included PTV TV, ranging from 35% to 100% (mean 54%, standard deviation 29.53) and 100% in two out of 31 patients.
Conclusion: Our study has shown that pre-operative PET-CT cannot be used to determine the BV in patients who replaced surgical clips and had undergone breast-conserving surgery. To define a more accurate BV, surgical clips should be placed in four planes, and more PTV margins should be given in treatment planning.

Keywords: Boost volume, breast cancer; positron emission tomography/computed tomography; radiotherapy; surgical clips.

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Cerrahi Öncesi 18 FDG/PET-BT’nin Meme Koruycu Cerrahi sonrasýnda Adjuvan Radyoterapide Boost Hacminin Belirlenmesinde Etkinliði

Berrin Inanc¹, Kubilay Inanc², Begum Okten¹, Ozlem Mermut^1
1Saðlýk Bilimleri Üniversitesi, Ýstanbul Eðitim ve Araþtýrma Hastanesi, Radyasyon Onkolojisi Anabilim Dalý, Ýstanbul
²Saðlýk Bilimleri Üniversitesi, Þiþli Hamidiye Etfal Eðitim ve Araþtýrma Hastanesi, Radyasyon Onkolojisi Anabilim Dalý, Ýstanbul

Amaç: Meme radyoterapisi sýrasýnda Boost hacmini belirlemek bazen zor olabilir, bu nedenle cerrahi klipsler günümüzde yaygýn olarak kullanýlmaktadýr.Bazen cerrahi klipsler Boost hacmini belirlemekte yetersiz kalabilir, baþka görüntüleme yöntemi gerekeli olur.Biz bu çalýþmamýzda, cerrahi öncesinde çekilen 18-FDG /PET-BT’nin Boost hacminin belirlenmesideki etkinliðini agöstermeyi amaçladýk.
Yöntemler: Meme koruyucu cerrahi sýrasýnda cerrahi klips yerleþtirilen ve cerrahi öncesinde 18-FDG /PET-CT’si bulunan otuz hasta incelendi.Boost hacmi planlama tomograsinde ve cerrahi öncesinde 18-FDG /PET-BT’sinde ayný radyasyon onkoloðu tarafýndan belirlendi.Her iki hacim birbiri üstüne füzyon yapýldý.Her iki hacminde orta noktasý belirlenip hacimlerin ortalama farklarý ölçüldü ve planlama tomograsindeki Boost hacmi (PTV-BV), PET-BT’deki tümör hacmi( PET-CT TV)’nin yüzde kaçýný içerdiði hesaplandý.
Bulgular: Hastalarýn yaþ ortalamasý 52 (25-72 yaþ)’dur.Cerrahi öncesi PET-BT TV ortalama 8.89 cm3 ( 1.00-64.30 cm3). PTV-BV’nin ortalama hacmi 6.92 cm3 (12.57-123.07 cm3).Her iki hacmin orta noktalarýndan, X (Coronal) düzlemde ortalama 1.76 cm (0.90-3.50), Y(aksiyel) düzleminde ortalama 1.73 cm (0.60-3.60), Z (sagittal) düzleminde ortalama1.20 cm(0.40-2.80) fark tespit edildi.Üç düzlemdeki fark istatiksel olarak anlamlý bulundu (p<0.001).PTV BV ortalama %54±29.53 (%35-%100) oranýnda PET-BT TV’ni içerir ve 30 hastanýn 2 tanesinde
PET-BT TV’ü PTV BV’nin tamanen dýþýndadýr.
Sonuç: Meme koruyucu cerrahi sonrasýnda cerrahi klips yerleþtirilen hastalarda boost hacminin belirlenmesinde cerrahi öncesi çekilen PET-BT kullanýlmamalýdýr.Daha doðru bir boost hacmi tanýmlanmasý için cerrahi klipsler 4 düzleme yerleþtirilmeli ve tedavi planlanmasýnda daha fazla PTV marjlarý verilmesi gerekir. (SETB-2019-12-156)

Anahtar Kelimeler: PET-BT, Boost hacmi, meme kanseri, cerrahi klipsler, radyoterapi

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