Study of occult uterine perforation in brachytherapy of cervical cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective:To evaluate the difference of dosimetry between three-dimensional and two-dimensional plans based on CT images of occult perforation in brachytherapy of cervical cancer, aiming to provide clinical reference.Methods:A total of 817 patients with cervical cancer received simple intrauterine (intrauterine tandem plus vaginal colpostats) three-dimensional brachytherapy in Chongqing University Cancer Hospital from January 2019 to December 2020 were retrospectively reviewed. Among them, 16 patients had occul uterine perforation. Based on Oncentra Brachy Therapy plan system, the single prescription dose was 6Gy. Three-dimensional (3D group) and two-dimensional (2D group) plans were designed on the perforated CT images The target volume, conformal index (CI), conformal index coformity index (COIN) and organs-at-risk (OAR) D 2cm 3 parameters were used to assess the plans between two groups. Results:The incidence of pccult uterine perforation was 1.96%(16/817) during brachytherapy for cervical cancer. The volume of prescription dose curve in the 3D group was (40.74±14.98) cm 3, significantly smaller compared with (91.46±19.71) cm 3 in the 2D group ( P<0.05), whereas the volume of the high-risk clinical target area wrapped by prescription dose curve did not significantly differ between two groups ( P>0.05). The CI and COIN in the 3D group were 0.79±0.10 and 0.72±0.96, significantly higher compared with 0.38±0.09 and 0.37±0.18 in the 2D group (both P<0.05). The D 2cm 3 of bladder, rectum, sigmoid colon, small intestine in the 3D group were (306.06±77.57) cGy, (252.27±72.60) cGy, (127.25±62.84) cGy and (228.79±94.90) cGy, significantly lower than (548.03±164.21) cGy, (411.16±118.74) cGy, (227.45±94.48) cGy and (450.95±157.96) cGy in the 2D group (all P<0.05). Conclusions:Application of image guidance in brachytherapy of cervical cancer is helpful to detect occult uterine perforation. When occult uterine perforation occurs, the use of three-dimensional plan can basically meet the clinical needs, which is significantly better than the two-dimensional plan.