Consensus and controversies on delineation of radiotherapy target volume for patients with non-small cell lung cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective To investigate the consensus and controversies on delineation of radiotherapy target volume for patients with non-small cell lung cancer(NSCLC). Methods Study questionnaires were designed by radiation oncologists in Peking University School of Oncology. The forms were sent through email to radiation oncologists in 10 radiation departments in China and 2 departments in US in November,2007. The brief introduction and PET/CT digital data of one patient with NSCLC were sent to radiation oncologists in 10 departments in Beijing. On Jan. 12,2008,the case discussion was held by more than 300 radiation oncologists from Beijing,Tianjin, Hebei, Liaoning Province and Inner Mongolia Autonomous Region. Results All receivers of the questionnaire responded . The set up error was 5-7 mm . For patients with locally advanced NSCLC treated with radiotherapy concurrently with near full dose chemotherapy,ll out ot 12 responding departments defined planning target volume(PTV) of primary tumor as gross tumor volume(GTV) plus 6-8 nun plus set-up error and respiratory movements ,and only one defined PTV as GTV plus set-up error and respiratory movements. For PTV of the mediastinal lymph nodes in the same patient,9 out of 12 responding departments defined PTV as GTV plus 6-8 mm plus set-up error and respiratory movements,and 3( of China) out of 12 defined PTV as GTV plus set-up error and respiratory movements. Stereotactic body .radiotherapy with high fraction dose was used in 11 out of 12 responding departments with fraction dose varying from 6 to 20 Gy,including 6 of which defined PTV of primary tumor as GTV plus 6-8 mm plus respiratory movements and set-up error, and 5 defined PTV of early stage lung cancer as GTV plus respiratory movements and set-up error. The consensus on delineation of primary tumor of the case discussion was that the appropriate window width and window level were 1600 Houasfield Units(HU) and -600 HU for lung window,and 400 HU and 20 HU for mediastinal window. The controversies was focused on whether the CTV for metastatic lymph nodes should be restricted as GTV plus 6-8 mm or enlarged to enclose all the involved lymph node region. Conclusions PIT of primary tumor and mediastinal metastatic lymph nodes should be GTV plus 6-8 mm plus respiratory movements plus set-up error. The basic controversies of target delineation are focused on the fraction dose and PIT range for early stage NSCLC, and on the possibility of defining the PIT as GTV plus respiratory movements and set-up error when treated with concurrent radiotherapy and full dose chemotherapy for locally advanced NSCLC.