Brachytherapy seed migration to the lung is a known complication of radioactive seed therapy. These seeds are used for localized treatment of malignancies, most commonly prostate cancer.
Regarding staging, nearly 79% of the cases are localized, 12% are regional and 5% present with distant disease 1. Currently, there are several management options for prostate cancer, including active surveillance, radical prostatectomy and radiation therapy (external beam and brachytherapy).
The most frequent site of seed migration is the lung. Sugawara et al. reported 0.36% of implanted seed migration to the chest in 20% of patient population 2.
The proposed migration route is via the periprostatic veins to the iliac veins, right heart and then the lungs 3. Migration to the heart, coronary arteries, liver, bladder, renal arteries and testicular vein has also been reported 4-11.
The majority of the cases are asymptomatic and incidentally found.
Nonetheless, several reports describe symptomatic presentation with hematuria, flank and back pain, chest pain, acute myocardial infarction, acute cardiac dysrhythmia and testicular swelling 4-9,11.
Usually, only one or two seeds migrate, and therefore it has no significant effect on postimplant dosimetry 2.
On CT the migrated seed appears as a linear hyperdense structure, with extreme beam and streak artifacts relative to their small size.
Treatment and prognosis
The latest consensus guidelines for transrectal ultrasound-guided permanent prostate brachytherapy by the American Brachytherapy Society no longer recommends the use of imaging methods for the detection of seed migration 13. The American College of Radiology appropriateness criteria follows the same recommendations as the American Brachytherapy Society 14.
-  Davis BJ, Taira AV, Nguyen PL, et al. ACR appropriateness criteria: Permanent source brachytherapy for prostate cancer. (2017) Brachytherapy. 16 (2): 266-276. doi:10.1016/j.brachy.2016.10.002 - Pubmed
-  Davis BJ, Horwitz EM, Lee WR, et alJ. American Brachytherapy Society consensus guidelines for transrectal ultrasound-guided permanent prostate brachytherapy. (2012) Brachytherapy. 11 (1): 6-19. doi:10.1016/j.brachy.2011.07.005 - Pubmed
-  Miura N, Kusuhara Y, Numata K, et al. Radiation pneumonitis caused by a migrated brachytherapy seed lodged in the lung. (2008) Japanese journal of clinical oncology. 38 (9): 623-5. doi:10.1093/jjco/hyn063 - Pubmed
-  Zhu AX, Wallner KE, Frivold GP, et al. Prostate brachytherapy seed migration to the right coronary artery associated with an acute myocardial infarction. (2006) Brachytherapy. 5 (4): 262-5. doi:10.1016/j.brachy.2006.08.004 - Pubmed
-  Sachdeva S, Udechukwu NS, Elbelasi H, et al. Prostate brachytherapy seed migration to the heart seen on cardiovascular computed tomographic angiography. (2017) Radiology case reports. 12 (1): 31-33. doi:10.1016/j.radcr.2016.10.009 - Pubmed
-  Davis BJ, Bresnahan JF, Stafford SL, et al. Prostate brachytherapy seed migration to a coronary artery found during angiography. (2002) The Journal of urology. 168 (3): 1103. Pubmed
-  Davis BJ, Pfeifer EA, Wilson TM, et al. Prostate brachytherapy seed migration to the right ventricle found at autopsy following acute cardiac dysrhythmia. (2000) The Journal of urology. 164 (5): 1661. Pubmed
-  Chen WC, Katcher J, Nunez C, et al. Radioactive seed migration after transperineal interstitial prostate brachytherapy and associated development of small-cell lung cancer. (2012) Brachytherapy. 11 (5): 354-8. doi:10.1016/j.brachy.2011.12.003 - Pubmed
-  Sugawara A, Nakashima J, Kunieda E, et al. Prostate brachytherapy seed migration to a left varicocele. (2012) Brachytherapy. 11 (6): 502-6. doi:10.1016/j.brachy.2011.11.003 - Pubmed
-  Siegel RL, Miller KD, Jemal A. Cancer statistics, 2018. (2018) CA: a cancer journal for clinicians. 68 (1): 7-30. doi:10.3322/caac.21442 - Pubmed
-  Haroun RR, Nance JW, Fishman EK. Prostate Brachytherapy seed migration to the Bladder presenting with Gross Hematuria. (2016) Journal of radiology case reports. 10 (1): 22-6. doi:10.3941/jrcr.v10i1.2657 - Pubmed
-  Nguyen BD, Schild SE, Wong WW, Vora SA. Prostate brachytherapy seed embolization to the right renal artery. (2009) Brachytherapy. 8 (3): 309-12. doi:10.1016/j.brachy.2008.11.011 - Pubmed
-  Nguyen BD, Egnatios GL. Prostate brachytherapy seed migration to the left testicular vein. (2010) Brachytherapy. 9 (3): 224-6. doi:10.1016/j.brachy.2009.10.002 - Pubmed
-  Nguyen BD. Cardiac and hepatic seed implant embolization after prostate brachytherapy. (2006) Urology. 68 (3): 673.e17-9. doi:10.1016/j.urology.2006.03.056 - Pubmed
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