Dosimetric and clinical outcomes study of occult uterine tandem imperfect implantation in HDR-brachytherapy for cervical cancer.

To investigate the ramifications of dose alterations and clinical outcomes linked to imperfect uterine tandem implantation within high dose rate brachytherapy (HDR-brachytherapy) for cervical cancer. A retrospective analysis was conducted on imperfect intrauterine insertion images from November 2020 to July 2021. The physicist reconfigured two-dimensions (2D) and three-dimensions (3D) plans based on prescription (6 Gy) for both the imperfection (IM) and perfect (PER) implantation. A paired t-test was employed to assess (reference volume of clinical target volume) CTV, (reference isodose) V, (conformal index) COIN, (equivalent dose in 2-Gy fractions) EQD of (organs at risks) OARs, (tumor control probability) TCP, and (normal tissue complication probability) NTCP. Among 1742 brachytherapy insertions, 38 (2.18%) instances of imperfect images were identified in 24 out of 319 patients (7.52%). COIN > 0.64 met the prescribed requirements solely in the PER-3D group. For inadequate implantation, the IM-3D-group showed enhancements in EQD of OARs and NTCP for the rectum, sigmoid colon, and small intestine, whereas NTCP of the bladder was augmented in the IM-2D-group. Regarding anterior wall perforation, the IM-group exhibited increases in EQD and NTCP for the rectum and small intestine, along with EQD for the bladder in 3D. In the IM-2D-group demonstrated increases in EQD for the bladder, rectum, and small intestine, as well as NTCP for the sigmoid and small intestine. In cases of posterior wall perforation, the IM-3D-group showcased augmented EQD for the bladder and rectum, and NTCP for the rectum and sigmoid. Conversely, EQD was solely increased in the rectum in the 2D context. Finally, in instances of fundus perforation, the IM-group exhibited heightened EQD for the sigmoid. Imperfect uterine tube implantation leads to worse clinical outcomes and greater adverse reactions.