Potential advantage of studying the lymphatic drainage by sentinel node technique and SPECT-CT image fusion for pelvic irradiation of prostate cancer.
OBJECTIVE
This study aims to investigate the in vivo drainage of lymphatic spread by using the sentinel node (SN) technique and single-photon emission computed tomography (SPECT)-computed tomography (CT) image fusion, and to analyze the impact of such information on conformal pelvic irradiation.


METHODS
Twenty-three prostate cancer patients, candidates for radical prostatectomy already included in a trial studying the SN technique, were enrolled. CT and SPECT images were obtained after intraprostate injection of 115 MBq of 99mTc-nanocolloid, allowing identification of SN and other pelvic lymph nodes. Target and nontarget structures, including lymph nodes identified by SPECT, were drawn on SPECT-CT fusion images. A three-dimensional conformal treatment plan was performed for each patient.


RESULTS
Single-photon emission computed tomography lymph nodal uptake was detected in 20 of 23 cases (87%). The SN was inside the pelvic clinical target volume (CTV2) in 16 of 20 cases (80%) and received no less than the prescribed dose in 17 of 20 cases (85%). The most frequent locations of SN outside the CTV2 were the common iliac and presacral lymph nodes. Sixteen of the 32 other lymph nodes (50%) identified by SPECT were found outside the CTV2. Overall, the SN and other intrapelvic lymph nodes identified by SPECT were not included in the CTV2 in 5 of 20 (25%) patients.


CONCLUSIONS
The study of lymphatic drainage can contribute to a better knowledge of the in vivo potential pattern of lymph node metastasis in prostate cancer and can lead to a modification of treatment volume with consequent optimization of pelvic irradiation.
Krengli
Marco
M
Department of Radiotherapy, University of Piemonte Orientale, Novara, Italy. krengli@med.unipmn.it
Ballarè
Andrea
A
Cannillo
Barbara
B
Rudoni
Marco
M
Kocjancic
Ervin
E
Loi
Gianfranco
G
Brambilla
Marco
M
Inglese
Eugenio
E
Frea
Bruno
B
D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D010388:Pelvis / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy*; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D013382:Subtraction Technique; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*