Evaluation of the impact of integrated [18f]-fluoro- 2-deoxy-D-glucose positron emission tomography/ computed tomography imaging on staging and radiotherapy treatment volume definition of non- small cell lung cancer Ömer Sağer (*), Ferrat Dinçoğlan (*), Hakan Gamsız (*), Selçuk Demiral (*), Bora Uysal (*), Serdar Sürenkök (*), Kaan Oysul (*), Nuri Arslan (**), Murat Beyzadeoğlu (*) * Department of Radiation Oncology, Gulhane Military Medical Academy **Department of Nuclear Medicine, Gulhane Military Medical Academy Reprint request: Dr. Ömer Sağer, Department of Radiation Oncology, Gulhane Military Medical Academy, Etlik-06018, Ankara, Turkey E-mail: omersager@gmail.com Date submitted: January 03, 2012 • Date accepted: February 08, 2012 • Online publication date: September 12, 2012 ARAŞTIRMA/ORIGINAL ARTICLE Gülhane Tıp Derg doi:10.5455/gulhane.25723 © Gülhane Askeri Tıp Akademisi 2012 SUMMARY The aim of this study was to evaluate the impact of integrated positron emis- sion tomography (PET)/computed tomography (CT) imaging on staging and radiotherapy treatment volume definition of non-small cell lung cancer (NSCLC). Thirty-nine patients with NSCLC referred to the Department of Radiation Oncology of Gulhane Military Medical Academy, for radical radio- therapy between June 2011 and December 2011 were enrolled in this study. All patients underwent integrated PET/CT imaging in treatment position for initial assessment. For patients deemed suitable for radical radiotherapy, CT- based and integrated PET/CT imaging based radiotherapy treatment plans were generated to comparatively evaluate dose-volume parameters of both plans. Of the 39 patients initially assessed with integrated PET/CT imaging, 29 patients (74.4%) were deemed suitable for radical radiotherapy with cura- tive intent. Fifteen patients (38.5%) were upstaged after integrated PET/CT staging. Of the 29 patients treated with radical radiotherapy at our department using integrated PET/CT imaging based radiation treatment planning (RTP), gross tumor volume was decreased in 16 patients (55.2%) and increased in 13 patients (44.8%) by incorporating PET/CT into RTP. Integrated PET/CT imaging allows selection of patients eligible for radical radiotherapy along with tailoring of radiotherapy target volumes to prevent overtreatment and undertreatment. Key words: Non-small cell lung cancer, positron emission tomography, ra- diotherapy, treatment planning ÖZET Entegre [18f]-fluoro-2-deoksi-D-glikoz (FDG) pozitron emisyon tomografi/ bilgisayarlı tomografi görüntülemesinin küçük hücreli dışı akciğer kanseri evreleme ve radyoterapi tedavi hacim tanımlamasına etkisinin değerlen- dirilmesi Bu çalışmanın amacı entegre pozitron emisyon tomografi (PET)/bilgisayarlı tomografi (BT) görüntülemesinin küçük hücreli dışı akciğer kanseri (KHDAK) evrelemesi ve tedavi hacmi tanımlamasına etkisinin değerlendirilmesidir. Haziran 2011 ile Aralık 2011 arasında KHDAK tanısıyla Gülhane Askeri Tıp Akademisi (GATA) Radyasyon Onkolojisi Anabilim Dalı’na yönlendirilen 39 hasta çalışmaya dahil edilmiştir. Başlangıç değerlendirmesi için tüm hasta- lara tedavi pozisyonunda entegre PET/BT görüntülemesi yapılmıştır. Radikal radyoterapi için uygun olduğu değerlendirilen hastalara BT tabanlı ve entegre PET/BT görüntülemesi tabanlı iki ayrı planlama, doz-hacim parametrelerinin bu iki planlamada karşılaştırılması için yapılmıştır. Entegre PET/BT görüntüle- mesiyle başlangıç değerlendirmesi yapılan 39 hastadan 29’u (%74.4) küratif amaçlı radikal radyoterapi için uygun olarak değerlendirilmiştir. Entegre PET/ BT görüntülemesi sonrası 15 hastada (%38.5) evre atlaması görülmüştür. PET/BT’nin radyoterapi planlamasına dahil edilmesiyle kliniğimizde entegre PET/BT görüntülemesi tabanlı radyoterapi planlaması kullanılarak tedavi edi- len 29 hastadan 16’sında (%55.2) gros tümör hacmi azalmış, 13 hastada (%44.8) ise artmıştır. Entegre PET/BT görüntülemesi, fazla ve eksik tedavinin engellenmesi için radikal radyoterapiye uygun hastaların seçimiyle birlikte radyoterapi hedef hacimlerinin şekillendirilmesine imkan sağlar. Anahtar kelimeler: Küçük hücreli dışı akciğer kanseri, pozitron emisyon to- mografi, radyoterapi, tedavi planlaması 1 Introduction Lung cancer is the leading cause of cancer-related death worldwide and non-small cell lung cancer (NSCLC) comprises 75% to 80% of all lung cancer cases (1). Radiotherapy plays a central role in the management of NSCLC. Local control rates are im- proved with dose escalation, however, escalating the total radiation dose requires accurate target definition (2,3). Computed tomography (CT), the conventional imaging modality used in radiation treatment plan- ning (RTP) for NSCLC, may be insufficient to deter- mine the target volume in some circumstances such as atelectasis due to poor contrast between tumor and normal tissues. Inclusion of entire atelectasis may result in larger treatment volumes in some pa- tients leading to increased risk of treatment morbid- ity, which also limits the potential of dose escalation. Moreover, staging of the mediastinum with CT may not be accurate since the sole parameter to decide on lymph node involvement is a short axis diameter of 1 cm. In the study by Prenzel et al. 44% of lymph nodes <1 cm were reported to be malignant, whereas 77% of lymph nodes were benign (4). Thus, a major limitation of using CT alone in RTP for NSCLC is un- dertreatment owing to inaccurate mediastinal evalu- ation that may result in treatment failure. With the awareness of the uncertainity of CT to define treat- ment volumes in some circumstances, efforts have been focused on improving treatment volume defini- tion by incorporating other imaging modalities. Positron emission tomography (PET) with the glu- cose analog [18F]fluoro-2-deoxy-D-glucose (FDG) is a functional imaging modality which is increas- ingly being used in oncology for staging, restaging, You can cite this article as: Sağer Ö, Dinçoğlan F, Gamsız H, Demiral S, Uysal B, Sürenkök S, Oysul K, Arslan N, Beyzadeoğlu M. Evaluation of the impact of integrated [18f]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography imaging on staging and radiotherapy treatment volume definition of non-small cell lung cancer. Gülhane Tıp Derg/Gulhane Med J 2012; doi:10.5455/gulhane.25723