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Table 2: The mean of movement in all directions and the mean bladder volume for each patient
Dimensions
Patient No. Lateral (X), cm Anteroposterior (Y), cm Superoinferior (Z), cm Bladder volume, L
1 0.16 - 0.3 - 0.06 0.031
2 0.1 - 0.133 0.1 0.111
3 0.2 1.32 - 0.24 0.151
4 - 0.6 - 2.28 0.16 0.189
5 0.25 1.15 0.55 0.157
6 - 0.08 1.04 - 0.4 0.113
7 0.45 - 0.75 - 0.225 0.062
8 0.3 1.15 - 0.05 0.125
9 - 0.06 0.6 - 0.12 0.088
10 0.36 0.55 - 0.2 0.067
11 0.4 0.3 - 0.15 0.046
12 0.1 0.04 - 0.36 0.064
13 - 0.12 0.18 0.56 0.055
14 0.1 0.3 0.71 0.049
15 0.3 0.4 0.4 0.076
16 0.31 - 1.21 - 0.35 0.140
17 - 0.1 - 0.53 0.21 0.096
18 0.2 0.67 0.6 0.090
19 - 0.45 0.45 - 0.34 0.070
20 0.15 - 0.22 - 0.56 0.040
21 0.2 0.71 0.43 0.083
22 0.3 0.51 0.25 0.066
23 - 0.21 0.81 0.16 0.100
24 0.14 0.91 - 0.22 0.105

Table 3: The comparison of the magnitude of uterine position in all directions.
displacements between current study and the study of
Taylor et al. [11] In our study the mean bladder volume was 90.55 mL and it
Magnitude of displacement, cm was shown that major shift occurred if the bladder volume
exceeded 100 mL. We expected a mean bladder volume
Dimensions Mean (SD) Median Range of 80 to 120 mL during IMRT in all our patients and this
Present study was corroborated on the weekly CBCT scans. Despite
Lateral 0.23 (0.22) 0.2 - 0.6 to 0.45 maintaining a standard bladder volume, we saw a uterine
Anteroposterior 0.67 (0.83) 0.57 - 2.28 to 1.3 shift daily.
Superoinferior 0.29 (0.40) 0.24 - 0.36 to 0.71 In a similar study by Taylor et al., in addition to the uterus,
[11]
[11]
Taylor et al. study the movement of the cervix was assessed to determine the
Lateral 0.08 (0.13) 0.0 0 to 0.5 internal margin for radiotherapy. They concluded that an
Anteroposterior 0.7 (0.9) 0.5 0 to 0.48 asymmetrical margin with CTV-PTV expansion of the
Superoinferior 0.71 (0.68) 0.5 0 to 0.32 uterus and cervix was needed during the treatment while
An assessment of interfractional uterine and cervical motion: they emphasized on the need for a strict bladder and rectum
filling protocol during treatment. Very few studies have
[11]
implications for radiotherapy target volume definition in
gynaecological cancer documented the changes in uterine position during the
radiotherapy course. An association between bladder filling
Table 4: Adverse effects of radiotherapy in twenty-four and uterine movement was reported by Buchali et al. [12]
participants that indicated no major AP change in cervical position. A
Frequency of toxicity, % maximum mean displacement in AP direction was seen in
Grade 1 Grade 2 our study. In contrast, the mean displacement in SI direction
Dysuria 80 20 was also substantial in the study by Taylor et al. [Table
[11]
Urinary frequency/urgency 90 10 3 and Figure 4]. The difference might be due to strict
Diarrhea 95 5
adherence to the bladder-bowel filling protocol in our study
positional change were significant, which suggested the as well as once weekly CBCT instead of two imaging on
importance of accurately determining the target mobility two consecutive days in their study.
for the conformal treatment. However, in that study, two There is a definite association between the bladder filling
sets of magnetic resonance images were taken in the supine and rectum emptying with uterine cervix movement. In
position without a small bowel displacement system (SBDS) addition, this association has been demonstrated by studies
while the patients were treated in prone position with a that have assessed the association of the bladder and rectum
SBDS placed under the patient’s abdomen. We studied volume with the displacements of the uterus and the cervix
the uterine motion once a week during the full course of respectively. Moreover, maximum uterine motion at the
radiotherapy and every time, we found a significant shift in fundus emphasizes on the need to contribute a variable

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Journal of Cancer Metastasis and Treatment ¦ Volume 2 ¦ April 15, 2016 ¦