Pattern of occult nodal relapse diagnosed with (18)F-fluoro-choline PET/CT in prostate cancer patients with biochemical failure after prostate-only radiotherapy.
BACKGROUND
The purpose of this study was to describe the pattern of nodal relapse with (18)F-fluoro-choline (FCH) Positron Emission Tomography/Computerized Tomography (PET/CT) in prostate cancer patients after radiotherapy.


METHODS
Eighty-three patients had a FCH PET/CT at time of biochemical failure. Of 65 patients with positive findings, 33 had positive nodes. This analysis included 31 patients who had undergone prior prostate-only radiotherapy with or without a prior radical prostatectomy. Each FCH positive node was assigned to a lymph node station with respect to the CTV defined by the RTOG guidelines (CTVRTOG). 3D mapping was performed after each node was manually placed in a reference planning CT scan after automatic co-registration of the two scans based on bone anatomy. Eighteen patients (58%) underwent focal salvage FCH PET-guided stereotactic radiotherapy with no hormones.


RESULTS
Fourteen patients (45.2%) had a relapse outside the CTVRTOG. Of the 17 patients with a positive node inside the CTVRTOG, 15 had a single node (88.2%) while seven patients out of the 13 evaluable patients (53.9%) who had a relapse outside the CTVRTOG had ⩾2 positive nodes on FCH PET/CT (OR=8.75, [95% CI: 1.38-54.80], p=0.020). Relapses that occurred outside the CTVRTOG involved the proximal common iliac (19.3%) and lower periaortic nodes (19.3%) up to L2-L3.


CONCLUSIONS
3D mapping of nodal relapses evaluated with FCH PET/CT suggests that with IMRT the upper field limit of pelvic radiotherapy could be extended to L2-L3 safely to cover 95% of nodal stations at risk of an occult relapse.
Lab of Imaging Engineering (Le2I), IMAC Core, CNRS-UMR 6306, University of Burgundy, Dijon, France; Department of Radiation Oncology, University Hospital Jean Minjoz, Besançon, France.
Alexis
A
Lépinoy
Lab of Imaging Engineering (Le2I), IMAC Core, CNRS-UMR 6306, University of Burgundy, Dijon, France; Department of Nuclear Medicine, Georges François Leclerc Cancer Center, Dijon, France.
Alexandre
A
Cochet
Department of Biostatistics, Georges François Leclerc Cancer Center, Dijon, France.
Adèle
A
Cueff
Department of Urology, University Hospital Le Bocage, Dijon, France.
Luc
L
Cormier
Department of Radiation Oncology, Georges François Leclerc Cancer Center, Dijon, France.
Etienne
E
Martin
Department of Radiation Oncology, Georges François Leclerc Cancer Center, Dijon, France.
Philippe
P
Maingon
Department of Radiation Oncology, University Hospital Jean Minjoz, Besançon, France.
Jean François
JF
Bosset
Lab of Imaging Engineering (Le2I), IMAC Core, CNRS-UMR 6306, University of Burgundy, Dijon, France; Department of Nuclear Medicine, Georges François Leclerc Cancer Center, Dijon, France.
François
F
Brunotte
Lab of Imaging Engineering (Le2I), IMAC Core, CNRS-UMR 6306, University of Burgundy, Dijon, France; Department of Radiation Oncology, Georges François Leclerc Cancer Center, Dijon, France. Electronic address: gcrehange@cgfl.fr.
Gilles
G
Créhange
D002794:Choline / Q000031:analogs & derivatives*; D005462:Fluorine Radioisotopes; D006801:Humans; D007610:Kallikreins / Q000032:analysis; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D064847:Multimodal Imaging / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D049268:Positron-Emission Tomography / Q000379:methods; D017430:Prostate-Specific Antigen / Q000032:analysis; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D019275:Radiopharmaceuticals; D016879:Salvage Therapy; D014057:Tomography, X-Ray Computed / Q000379:methods
D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; C514960:fluorocholine; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen; D002794:Choline
(18)Fluoro-choline; Nodal relapse; PET/CT; Prostate cancer; Whole pelvic radiotherapy