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OBJECTIVE:  It is considered appropriate to simulate an empty bladder and rectum before  treatment planning of vaginal cuff brachytherapy. However, the use of a Foley catheter to empty the bladder in each fraction can affect the treatment compliance and quality of life of the patients. In this study, it was aimed to determine the effect of Foley catheter on bladder fullness and the changes caused by the doses received by other critical organs and target volumes in patients who underwent vaginal cuff BRT.

MATERIAL METHODS: Twenty patients with a diagnosis of postoperative endometrial or cervical cancer who underwent 3-dimensional vaginal high-dose rate (HDR-BRT) using a multi-channel cylinder between January 2020 and May 2021 were examined dosimetrically. Rectum emptied using enema in all patients before the first fraction. After evacuation of the urine, two simulation CT scans were performed with and without inserting a foley catheter. Target volumes and critical organs were contoured in accordance with the guidelines in both treatment planning CT scan slices. The treatment plan, which was approved in the planning CT with the Foley, was transferred to the CT withoutFolet, and the dose volume histogram (DVH) parameters were evaluated separately. For both planning, first of all, the volumes of HRCTV and critical organs and the D90, D95 and D98 values ​​obtained by HRCTV; also the doses of 0.1 cc, 1 cc and 2 cc of each critical organ like bladder, rectum and sigmoid were recorded separately. Paired sample t-test was used to determine the statistical difference between both planning DVH parameters, p>0.05 was considered significant.

RESULTS: The median age of the patients was 60 years (35-79). The median ECOG performance score was 1 (0-2) and 75% (n=15) had additional comorbidities. Half of the patients were obese, and the median body mass index (BMI) in all patients was 34 kg/m2 (20-40). Vaginal cuff BRT was applied to 16 patients diagnosed with endometrial cancer and 4 patients with cervical cancer. Median 50.4 Gy (45-50.4 Gy) external RT was applied to 12 patients with a total of 15 Gy BRT boost in 3 fractions. A total of 27.5 Gy HDR-BRT in 5 fractions was applied to 8 endometrial cancer patients. No significant difference was found between target and critical organ volumes when the DVH parameters of the planning with and without the Foley catheter were evaluated. In addition, no statistically significant difference was found between the two plans in terms of target and critical organ doses such as HRCTV D90, D95, D98 and D0.1, D1, D2cc of critical organs. DVH information related to volume and doses are summarized in Table-1.

Table-1. Dosimetric analysis of target volumes and organs at risk

CONCLUSION: It is not necessary to empty the bladder by inserting a Foley catheter before the vaginal cuff BRT treatment.It seems to be sufficient to simulate and treat the patient by just emptying the urine.