Transcript open "060433_ASTRO_2009_Updated_Poster"

Routine Use of Intraoperative Ultrasound Guidance during Intracavitary
Brachytherapy Applicator Placement in Cervical Cancer: the University of
Alabama at Birmingham (UAB) Experience
Philip E. Schaner*, Jimmy J. Caudell*
†,
Jennifer F. DeLos Santos*, Sharon Spencer*, Sui Shen*, Robert Y. Kim*
*Department of Radiation Oncology, University of Alabama at Birmingham
†Department of Radiation Oncology, University of Mississippi Medical Center
BACKGROUND
Intracavitary brachytherapy (ICBT) facilitates a high radiation dose to cervical
cancer with relative sparing of normal tissues. However, insertion of the tandem
into the uterine cavity may be technically challenging, and acute operative
complications such as uterine perforation are possible. Intraoperative ultrasound
(IUS) has the potential to minimize these complications and facilitate successful
ICBT. At the University of Alabama at Birmingham, IUS has been routinely used
for cervical ICBT procedures since 1999. The objective of this study was to
examine the ten year experience using this modality at UAB.
RESULTS
Table 1: Patient Characteristics
Characteristics
Patients (n,%)
Median Age (yr)
50 (24-92)
Treatment Modality
HDR
104 (42.7%)
LDR
139 (57.3%)
All 243 patients completed ICBT. Five of 356 (1.4%) IUS-guided applicator placements resulted in uterine perforation, three of which
were lateral (Table 2). These patients all underwent successful tandem insertion on the second attempt (Figure 1). No significant
clinical sequelae occurred after perforation. When lateral perforation occurred, the tandem appeared within the uterine corpus on
sagittal IUS imaging (Figure 2A). Axial IUS imaging through the fundus was found necessary to rule out a lateral perforation (Figure
2C-D). No suboptimal placements requiring return to the operating room occurred.
HDR by FIGO Stage
MATERIALS AND METHODS
Clinical and radiological data were retrospectively gathered for all cervical
cancer patients who underwent tandem-based ICBT applicator placement as a
component of definitive radiation from 1999 to 2008. Of the 259 patients meeting
those criteria, IUS was utilized in 243. Table 1 displays the patient distribution by
FIGO stage and treatment modality.
Real-time abdominal IUS (currently an iU22 Philips Ultrasound System with
C5-1 probe at 19 -22 Hz) was performed in all study patients. Images were
acquired in both the sagittal and axial planes in most patients. One hundred
eighty cc of normal saline was typically instilled into the bladder to enable IUS.
IUS was initiated prior to introducing the uterine sound. The cervix was dilated
under real-time IUS guidance. Following dilation, the tandem was inserted and
optimal positioning was confirmed using IUS. IUS was discontinued after
securing the device and confirming the final implant position.
The majority of patients received pelvic external beam radiotherapy (EBRT)
to 45 - 50.4 Gy prior to ICBT. Most patients completed ICBT within three months
of finishing EBRT. A Fletcher-Suit-Delclos applicator with Cesium-137 was used
for low dose rate (LDR) brachytherapy. From 1999-2006, a Nucletron applicator
was used for high dose rate (HDR) brachytherapy. A Varian HDR brachytherapy
applicator has been used since 2006. Iridium-192 was used for all HDR
procedures.
Prior to mid-2007 fluoroscopy was used for treatment planning; computed
tomography (CT) of the pelvis was performed only in cases where insertion was
difficult or perforation was suspected. Since mid-2007, CT imaging has been
performed on all HDR procedures for treatment planning. LDR patients typically
received a cumulative dose (with EBRT) of 80-90 Gy to point A. From 1999 to
2006, HDR brachytherapy patients generally received five 600 cGy fractions
prescribed to point A. Since 2007 most HDR brachytherapy patients have
received three 800 cGy fractions prescribed to point A.
I
28
(26.9%)
IIA
13
(12.5%)
IIB
44
(42.3%)
IIIA
1
(1.0%)
IIIB
15
(14.4%)
IV
3
(2.9%)
I
29
(20.9%)
IIA
10
(7.2%)
IIB
59
(42.4%)
IIIA
1
(0.7%)
IIIB
32
(23%)
IV
8
(5.8%)
LDR by FIGO Stage
Figure 1: Lateral perforation and resolution. Axial (A) and
coronal (B) CT scan after applicator placement. The tandem
(white arrow) perforated the uterine serosa, and the device
was then removed. Axial (C) and coronal (D) CT scan of the
same patient after insertion of a 2nd applicator two days
later. The tandem (black arrow) is now centrally placed in
the uterus. Note blood within the false passage caused by
the initial perforation (white arrow). Abbreviations: U =
uterus.
IUS guided brachytherapy
Total
356
HDR
120 (33.7%)
LDR
236 (66.3%)
Table 2: Characteristics of Patients Perforated during ICBT Applicator Placement
Patient
Age
FIGO Stage
Type of Brachytherapy
Uterine Position
Site of Perforation
1
49
IIIB
HDR
Retroflexed
Lateral
2
84
IIB
HDR
Anteflexed
Lateral
3
48
IIIB
LDR
Anteflexed
Lateral
4
50
IIIB
LDR
Neutral
Anterior
5
53
IIB
LDR
Anteflexed
Posterior
Figure 2: Identifying lateral perforation on IUS. (A) IUS (sagittal view) shows tandem
(white arrowheads) within the uterus (black arrowheads), despite a lateral perforation.
Note the asymmetrically thick myometrium relative to the tandem. (B) IUS (sagittal
view) during the 2nd procedure two days later. Note the central location of the tandem
within the uterus. IUS, axial view, at the levels of the cervix (C) and fundus (D) during
the 2nd procedure, prior to placing the uterine sound. The Smit’s sleeve (white
arrowhead) inserted during the 1st procedure is centrally visible within the uterus. In (D)
the Smit’s sleeve is laterally evident where perforation occurred, and the endometrial
cavity is centrally visible (grey arrowhead). Abbreviations: b = bladder.
CONCLUSIONS
These data indicate a 1.4% risk of uterine perforation over the course of a
ten year experience with routine IUS; in no case did technical limitations
prevent final ICBT delivery. IUS minimizes the possibility of repeat
procedures, uterine perforation, and poor outcomes secondary to toxicity or
inadequate tumor dose due to device placement. More importantly, it
increases the probability of successful ICBT. It is worth considering routine
IUS implementation as a component of ICBT applicator insertion.