Severe toxicity after permanent radioactive seed implantation for mediastinal carcinoid tumors

Abstract 

Purpose

Permanent implantation of ¹²⁵I seeds may be used when uninvolved surgical margins are unobtainable or close. Two cases of mediastinal carcinoid tumors with prior chemoradiation had tumors adherent to esophageal muscularis. Both underwent intraoperative permanent seed implantation and developed esophageal fistulas requiring surgical correction.

Methods and materials

Custom permanent ¹²⁵I seed mesh implants were fashioned intraoperatively in a geometrically coherent pattern. The implants were directly sutured to the partially resected esophageal wall. The postimplant CT scans were fused with the postfistula scans to provide dosimetric information at the fistula site. Doses were calculated from time of insertion to time of fistula formation. Neither patient showed evidence of disease recurrence at the time of fistula repair.

Results

Patient 1 developed an esophageal-pleural fistula 83 days after seed implantation. Patient 2 developed a broncho-pleural fistula 300 days after seed implantation.

Conclusions

These cases demonstrated that implantation in the setting of extensive subcarinal space dissection and partial esophageal wall resection could cause fistula formation and the need for additional surgery. The high mucosal dose, despite the relatively low activity implant, was due to lack of geometric sparing of the mucosa. We recommend that extensive subcarinal space dissection be considered a contraindication to permanent seed implantation.

Keywords: Fistula formation, Interstitial brachytherapy, Seed implant, Mediastinal carcinoid