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  • br Discussion br Interstitial brachytherapy has

    2019-11-11


    Discussion
    Interstitial brachytherapy has been shown to be effective at controlling locally advanced gynecological tumors in the pelvis (1,6,12,13). Data from RetroEMBRACE suggests that the use of interstitial needles in large cervical cancers improves local control by 10% (1). Although this technique has been available for decades, there has been reluctance to 
    interstitial approaches due to lack of expertise and concern of complications. In a Canadian survey, only half of the re-sponding centers indicated that they were performing ISBT, whereas 96% of them are using 3D imageeguided planning (14). Many radiation oncologists feel that it is necessary to integrate surgical guidance (laparotomy or laparoscopy) with P-ISBT to view the insertion of catheters in real-time
    (8). However, this resource is not readily available, can lead to surgical complications and requires additional operative time (8,15).
    With the advent of 3D imageebased planning, it is possible to avoid loading needles within or close to organs and P-ISBT complications can thereby be limited. It may be that the higher rates of toxicity previously seen with 2D planning for interstitial (3) are partly associated with the limitations of outdated brachytherapy dosimetry and not from any physical needle injury. We hypothesize that this is the case and that catheter injuries are rare from inter-stitial brachytherapy. With mounting evidence for the inte-gration of ISBT into treatment of gynecologic tumors, barriers and myths regarding these complications should not impede the development of such a program.
    This prospective study quantifies radiological organ intrusion and rates of acute complication associated with P-ISBT. Overall, 73 procedures were analyzed in this study with a total of 48 pelvic organs intruded by interstitial
    Table 3
    Acute complications after perineal interstitial brachytherapy
    Type Total G1 G2 G3 G4
    Table 4
    Grade 2 hematuria events vs Phosphatase Inhibitor Cocktail II intrusion and number of needles
    Bladder intrusion
    Mean (SD) number of
    Grade 2 hematuria Yes No p-value needles in the bladder p-value
    SD 5 standard deviation.
    catheters. Only nine acute complications potentially attrib-uted to catheter intrusions were seen, with only two Grade 3 complications. One patient had vaginal bleeding after applicator removal requiring transfusion and another devel-oped a pelvic abscess, 2 months after interstitial insertion, requiring intravenous antibiotic treatment.
    Organ intrusion is a common event in patients with locally advanced or recurrent gynecological cancers treated with P-ISBT. Shah et al (16) have reported that 53% and 72% of the patients had their bladder or bowel, respectively, intruded. Nevertheless, no additional toxicities were seen in their cohort of patients if compared with previous series us-ing real-time intraoperative guidance (laparoscopy, ultra-sound, and fluoroscopy) (8). Likewise, only four of these events can be attributed by visceral intrusion of 9 patients presented with postprocedure complications associated with catheters in our series. As the risk of organ damage related with needle intrusion to pelvic organ is low, real-time image-guidance or laparoscopic guidance is not a prerequisite to developing an ISBT program. The use of intraoperative transrectal ultrasound, however, may reduce the number of pelvic organ intrusions (17) while assessing needle distribution within the high-risk CTV.
    Hematuria was the only complication that could be directly correlated with organ intrusion, as 3 of 18 patients with bladder intrusion were found to have Grade 2 hematu-ria. These patients had higher number of needles intruding the bladder in comparison with patients with bladder intru-sion and no urinary bleeding. Nevertheless, most patients with bladder intrusion did not have any significant urinary complication, and those that did, had low grade hematuria not requiring transfusion. A case-report described by Ross-man et Phosphatase Inhibitor Cocktail II al. illustrates the low morbidity rate associated with bladder intrusion, as no hematuria or other urinary compli-cation were seen in a patient with a proven bladder intru-sion by a tandem applicator (18).