In this study,
we have presented that routine ultrasound guidance during intracavitary brachytherapy for cervical cancer patients may result in appropriate insertion and very low rates of uterine perforation.
Previous studies have shown perforation rates ranging from 1.4 to 13.7% [4-9].
Before ultrasound guidance in our patients,
our perforation rate was 6.9%,
but after ultrasound guidance perforation was detected only in one patient (0.9%).
Since perforation may lead to direct trauma to the surrounding organs,
such as bladder and intestine,
and increases radiation dose to organs at risk,
it is important to lower perforation rates.
Although we have seen perforation in three patients,
there were no bowel or bladder perforation.
The uterine perforation typically occurs in the posterior cervix but it may also occur at the fundus; therefore,
a proper understanding of the uterine size,
position,
and flexion (e.g.
anteversion,
retroflexion) may be helpful in avoiding such occurrences [10].
In a large series by Schaner et al there were 5 perforations and 3 of them were lateral perforations [4].
Upon review of the ultrasound images,
it became evident that although sagittal ultrasound imaging indicated adequate tandem placement,
insufficient axial imaging was obtained and effective utilization of ultrasound requires at least 2 axial views,
one at the cervix and one at the uterine fundus.
When a perforation was diagnosed in our patients on planning CT imaging,
the applicators were removed and the patients were treated conservatively.
The patients were monitored for a minimum of 24 hours and administered prophylactic antibiotics.
In previous studies,
it has been demonstrated that appropriate intracavitary insertions improve pelvic control,
survival and decrease toxicity among patients with locally advanced cervical cancer [11,
12].
In our study,
the effects of optimal application on local control,
survival rates and late complications have not been examined.
When brachytherapy applicators are appropriately placed,
relatively high paracentral doses can be delivered that yield a high rate of central disease control with an acceptable rate of complications [12].
Several reports have described the use of ultrasound guidance in especially complex applicator placements [13].
Corn et al.
used ultrasound in challenging cases such as cervical os stenosis,
fibrosis,
indeterminate orientation of the endometrial cavity axis,
or previous perforation [14].
Mayr et al.
demonstrated that the use of ultrasound-guided uterine anteversion for brachytherapy implant placement was feasible and resulted in acceptable outcome and complication rates in a population otherwise difficult to manage and at high risk for uterine perforation [15].
In our study,
7% of patients had retroverted uterus and in 53.5% of patients the uterus was laterally deviated to right or left which also makes the insertion difficult and in these patients ultrasound guidance also helped to guide the tandem appropriately.
Portable transabdominal ultrasound machine is readily available at our radiation oncology department,
and it provides easy,
safe,
fast,
inexpensive and real time guidance during brachytherapy applications.
Applicator placement have been traditionally done “blindly” without ultrasound guidance and suboptimal placement can occur without awareness.
When a perforation is discovered on planning CT,
the applicators must be removed and a second procedure is scheduled,
this process is time consuming and expensive and may result in a treatment delay,
which is known to compromise local control [13].
The incorporation of ultrasound guidance in intracavitary brachytherapy in a previous study did not lengthen the time to complete the procedure and it decreased the average overall insertion time [8].
In conclusion,
the implementation of routine ultrasound guidance resulted in decreased rates of perforations and increased rates of accurate applicator placement.
Ultrasound imaging provided safe,
cost-effective and real-time guidance.
Also it is important for radiologists to be familiar with the appropriate positioning of applicator as well as any potential complications.