18FDG-PET based radiation planning of mediastinal lymph nodes in limited disease small cell lung cancer changes radiotherapy fields: a planning study.
OBJECTIVE
To investigate the influence of selective irradiation of 18FDG-PET positive mediastinal nodes on radiation fields and normal tissue exposure in limited disease small cell lung cancer (LD-SCLC).


METHODS
Twenty-one patients with LD-SCLC, of whom both CT and PET images were available, were studied. For each patient, two three-dimensional conformal treatment plans were made with selective irradiation of involved lymph nodes, based on CT and on PET, respectively. Changes in treatment plans as well as dosimetric factors associated with lung and esophageal toxicity were analyzed and compared.


RESULTS
FDG-PET information changed the treatment field in 5 patients (24%). In 3 patients, this was due to a decrease and in 2 patients to an increase in the number of involved nodal areas. However, there were no significant differences in gross tumor volume (GTV), lung, and esophageal parameters between CT- and PET-based plans.


CONCLUSIONS
Incorporating FDG-PET information in radiotherapy planning for patients with LD-SCLC changed the treatment plan in 24% of patients compared to CT. Both increases and decreases of the GTV were observed, theoretically leading to the avoidance of geographical miss or a decrease of radiation exposure of normal tissues, respectively. Based on these findings, a phase II trial, evaluating PET-scan based selective nodal irradiation, is ongoing in our department.
van Loon
Judith
J
Department of Radiation Oncology (Maastro Clinic), GROW Research Institute, University Hospital Maastricht, Maastricht, The Netherlands. judith.vanloon@maastro.nl
Offermann
Claudia
C
Bosmans
Geert
G
Wanders
Rinus
R
Dekker
André
A
Borger
Jacques
J
Oellers
Michel
M
Dingemans
Anne-Marie
AM
van Baardwijk
Angela
A
Teule
Jaap
J
Snoep
Gabriel
G
Hochstenbag
Monique
M
Houben
Ruud
R
Lambin
Philippe
P
De Ruysscher
Dirk
D
D018288:Carcinoma, Small Cell / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D003287:Contrast Media; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy*; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008482:Mediastinum; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18