A phase III randomised trial of trans-abdominal ultrasound in improving application quality and dosimetry of intra-cavitary brachytherapy in locally advanced cervical cancer.

Introduction: Intra-cavitary brachytherapy (ICB) remains an integral part of radiotherapy treatment in cervical cancer. Two-dimensional X ray point-based planning remains common and blind insertion leads to uterine perforations and higher toxicity. We conducted a randomised controlled trial of using trans-abdominal ultrasound in performing ICB to reduce perforation and organ at risk doses.

Patient And Methods: The present study is a phase III open label randomised controlled trial of ultrasound guided ICB conducted on invasive cervical cancer patients. Patients were randomised by a simple computer-generated randomization chart into Arm A (No Ultrasound guidance) and Arm B (ICB with ultrasound guidance). The uterine perforation rates, tandem length change rates, bladder doses, rectal dose and procedure times were compared. Fischer exact test was used to compare the arms and p value <0.05 considered significant.

Results: A total of 160 patients were randomised. With US assistance, the uterine perforation rate was 1.25% (n = 1). In the non-US assistance arm the perforation rate was 12.5% (n = 10) (p = 0.005). Mean time to complete the entire procedure was significantly shortened from 26 min to 19 min favouring the US arm (p = 0.001). Dosimetric assessment between the two groups showed significant decrease in dose received by the various organs at risk with US assistance.

Conclusion: The present study confirms significant improvement in application quality as well as dosimetry with reduction in procedure time. Trans-Abdominal US should be routinely used for ICB procedures, particularly in resource limited settings.