Case ReportAn unusual case of radioactive seed migration to the vertebral venous plexus and renal artery with nerve root compromise
Introduction
Radioactive seed brachytherapy implantation is commonly used in the treatment of localized prostate cancer. Seed migration is a well-documented complication and has been reported most commonly to the lungs [1], [2] with rates ranging from 0.7% to 55% [3], [4]. Embolization to uncommon sites, such as the right coronary artery resulting in myocardial infarction has also been reported (5). Migration to the vertebral plexus is very uncommon and to our knowledge only two cases have previously been reported (6). Here, we report an additional case resulting in nerve root compromise and subsequent migration to the renal hilum.
Section snippets
Case study
A 52-year-old male with low-risk adenocarcinoma of prostate with prostate-specific antigen level of 5.5, clinical stage T1c, Gleason score 3 + 3 = 6 was treated with low–dose rate brachytherapy. The preimplant ultrasound volume study of the prostate was measured at 42 cc. Subsequent planning was performed and 145.0 Gy was prescribed to the 100% isodose.
A total of 100 I-125 seeds with source activity of 0.368 mCi were peripherally loaded and were deployed with image intensifier and ultrasound guidance
Dosimetry study
A GEANT4 (7) Monte Carlo simulation of the single seed (Oncura 6711) (8) was performed. In this Monte Carlo study, the seed was given rotations in all three directions to match the CT data set and radiographic images. Two simulations were performed; one in a phantom with water only, and one in a voxelized phantom, including the bone material. The duration of exposure was a worst-case scenario of 60 days (i.e., from implant date to surgery date). The critical and nearby structures were contoured
Discussion
The vertebral venous plexus is a series of valveless epidural sinuses that extend from the coccyx to foramen magnum. Batson hypothesized that there is interconnectivity of this venous plexus from the pelvis to the cranium and that this system can provide a direct vascular route for spread of tumor cells, emboli, or infection [9], [10], [11], [12], [13], [14]. This theory of retrograde seeding may in part explain the predication of prostate cancer to the spine (15). Tumor cells may also
Conclusions
Seed migration to the vertebral venous plexus is uncommon and to our knowledge this is the third reported case. Its subsequent migration to the renal hilum is most unusual. CT with bony windows or MRI are required if this is suspected.
Although the dose to the nerve roots were estimated using the GEANT4 Monte Carlo simulation toolkit, it is unknown what the normal tissue tolerance is from low-dose rates.
Long-term followup is essential to monitor the patient for progression of radiation-induced
References (24)
- et al.
Implications of radioactive seed migration to the lungs after prostate brachytherapy
Urology
(2002) - et al.
Iodine 125 seed migration after prostate brachytherapy: A study of 170 patients
Cancer Radiother
(2004) - et al.
Reduction of radioactive seed embolization to the lung following prostate brachytherapy
Int J Radiat Oncol Biol Phys
(1998) - et al.
Radioactive seed migration to the chest after transperineal interstitial prostate brachytherapy: Extraprostatic seed placement correlates with migration
Int J Radiat Oncol Biol Phys
(2004) - et al.
Prostate brachytherapy seed migration to the right coronary artery associated with an acute myocardial infarction
Brachytherapy
(2006) - et al.
Migration of prostate brachytherapy seeds to the vertebral venous plexus
Brachytherapy
(2006) - et al.
GEANT4-a simulation toolkit
Nucl Instrum Methods Phys Res A
(2003) - et al.
Prostate brachytherapy seed embolization to the right renal artery
Brachytherapy
(2009) - et al.
Radiation-induced brachial plexus injury: Follow-up of two different fractionation schedules
Radiother Oncol
(1990) - et al.
Tolerance of peripheral nerve to intraoperative radiotherapy (IORT): Clinical and experimental studies
Int J Radiat Oncol Biol Phys
(1985)
Late radiation injury to muscle and peripheral nerves
Int J Radiat Oncol Biol Phys
Direct evidence that prostate tumors show high sensitivity to fractionation (low α/β ratio), similar to late-responding normal tissue
Int J Radiat Oncol Biol Phys
Cited by (9)
Revisiting the Vertebral Venous Plexus–A Comprehensive Review of the Literature
2021, World NeurosurgeryCitation Excerpt :Seeding of metastases to the VVP has been fairly well established in the literature, but 1 rare complication of prostate brachytherapy that has been reported is seed migration to the VVP using the pelvic venous pathway. There have been at least 4 reported cases in the literature of this finding, as reported by Nakano et al. in 2006,52 Wagner et al. in 2010,53 and Hau et al. in 2011.54 Similar to seed migration in brachytherapy for prostate cancer, there has been a report of pacemaker lead migration through the VVP into the spinal canal.55
Incidence and prediction of seed migration to the chest after iodine-125 brachytherapy for hepatocellular carcinoma
2017, BrachytherapyCitation Excerpt :The incidence of seed migration is reported to be between 1.7% and 69.4% (14). Various locations as sites of seed movement have been documented, including the lungs (14, 18), heart (19, 20), urine (20, 21), abdomen (20–22), pelvis (20, 22), vertebral venous plexus (23, 24), sacrum (20), seminal vesicles (22), and testicular veins (25). However, the most frequent site is the chest.
Seed migration in prostate brachytherapy depends on experience and technique
2012, BrachytherapyCitation Excerpt :Seed migration and seed loss in permanent seed prostate brachytherapy rarely influences cancer outcome and, only rarely, have clinical consequences. Rare locations of seed embolism are the vertebral venous plexus (1), the coronary artery (2), or the renal artery (1, 3). Nevertheless, the responsible physician tries to avoid it as much as possible.
Prostate brachytherapy seed migration to a left varicocele
2012, BrachytherapyCitation Excerpt :It is well known that the most frequent site of seed migration is the lungs. Rare cases of seed migration to a coronary artery, the right ventricle, the liver, the kidneys, Batson's vertebral venous plexus, and the left testicular vein have been reported (6–14). However, to date, no cases of seed migration to a varicocele have been reported.
Financial disclosure/Conflicts of interest: There are no financial disclosures or any conflicts of interest for either the first author or any of the coauthors.