Rectum and bladder spacing in cervical cancer brachytherapy using a novel injectable hydrogel compound.

PURPOSE: The aim of this study was to evaluate injection of a novel hydrogel (TraceIT; Augmenix, Waltham, MA) between the cervix, rectum, and bladder in female cadavers compared with, and in addition to, the current standard of gauze packing, for organ-at-risk sparing in cervical cancer brachytherapy planning.

METHODS AND MATERIALS: This brachytherapy cadaver study used T2-weighted MRI and CT imaging to compare three scenarios: (1) gauze packing alone, (2) hydrogel injection placed in the cervical fornices and rectovaginal septum, and (3) gauze packing in conjunction with hydrogel injection. Hydrogel distribution was evaluated. Doses to 2 cm3 volumes (D2cc ) for the rectum, bladder, and sigmoid were collected. Statistical significance (p < 0.05) was evaluated using a two-tailed paired t test.

RESULTS: Hydrogel was successfully injected to space the bladder and rectum from the cervix in all five cadavers. The spacer was easily identifiable on both CT and MRI. The use of hydrogel in addition to packing resulted in a 22% decrease in rectum D2cc dose (p = 0.02), a 10% decrease in bladder D2cc (p = 0.27), and no change in sigmoid D2cc dose. No difference was observed between hydrogel only vs. gauze packing only.

CONCLUSIONS: Our results revealed a significant clinically meaningful decrease in rectal D2cc associated with the use of hydrogel in addition to gauze packing-TraceIT hydrogel holds promise as a spacer in cervical cancer therapy.