Distribution of prostate sentinel nodes: a SPECT-derived anatomic atlas.
OBJECTIVE
The randomized Radiation Therapy Oncology Group 94-13 trial revealed that coverage of the pelvic lymph nodes in high-risk prostate cancer confers an advantage (progression-free survival and biochemical failure) in patients with ≥15% risk of lymph node involvement. To facilitate an improved definition of the adjuvant target volume, precise knowledge regarding the location of the relevant lymph nodes is necessary. Therefore, we generated a three-dimensional sentinel lymph node atlas.


METHODS
In 61 patients with high-risk prostate cancer, a three-dimensional visualization of sentinel lymph nodes was performed using a single photon emission computed tomography system after transrectal intraprostatic injection of 150 to 362 (median 295) mega becquerel (MBq) (99m)Technetium-nanocolloid (1.5-3 h after injection) followed by an anatomic functional image fusion.


RESULTS
In all, 324 sentinel nodes in 59 of 61 patients (96.7%) were detected, with 0 to 13 nodes per patient (median 5, mean 5.3). The anatomic distribution of the sentinel nodes was as follows: external iliac 34.3%, internal iliac 17.9%, common iliac 12.7%, sacral 8.6%, perirectal 6.2%, left paraaortic 5.3%, right paraaortic 5.3%, seminal vesicle lymphatic plexus 3.1%, deep inguinal 1.5%, superior rectal 1.2%, internal pudendal 1.2%, perivesical 0.9%, inferior rectal 0.9%, retroaortic 0.3%, superficial inguinal 0.3%, and periprostatic 0.3%.


CONCLUSIONS
The distribution of sentinel nodes as detected by single photon emission computed tomography imaging correlates well with the distribution determined by intraoperative gamma probe detection. A lower detection rate of sentinels in close proximity to the bladder and seminal vesicles is probably caused by the radionuclide accumulation in the bladder. In regard to intensity-modulated radiotherapy techniques, the presented anatomic atlas may allow optimized target volume definitions.
Ganswindt
Ute
U
Department of Radiation Oncology, Ludwig-Maximilians-University, Munich, Germany. ute.ganswindt@med.uni-muenchen.de
Schilling
David
D
Müller
Arndt-Christian
AC
Bares
Roland
R
Bartenstein
Peter
P
Belka
Claus
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008198:Lymph Nodes / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D008297:Male; D008488:Medical Illustration; D008875:Middle Aged; D009367:Neoplasm Staging; D010388:Pelvis / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy; D013668:Technetium Tc 99m Aggregated Albumin; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D013668:Technetium Tc 99m Aggregated Albumin; C083602:technetium Tc 99m nanocolloid