Sh. Herbert et al., VOLUMETRIC-ANALYSIS OF SMALL-BOWEL DISPLACEMENT FROM RADIATION PORTALS WITH THE USE OF A PELVIC TISSUE EXPANDER, International journal of radiation oncology, biology, physics, 25(5), 1993, pp. 885-893
Purpose: Many techniques and devices have been used in an attempt to m
inimize gastrointestinal morbidity of pelvic irradiation. The value of
a temporary intrapelvic tissue expander to displace small bowel from
pelvic radiotherapy fields was analyzed by comparing volumetric treatm
ent parameters of patients with and without such a device. Methods and
Materials: Between 1983 and 1991, 77 patients with a diagnosis of end
ometrial (n = 35), colorectal (n = 41), or anal carcinoma (n = 1) rece
ived adjuvant postoperative radiotherapy after undergoing treatment pl
anning simulation with the use of small bowel oral contrast medium. Fo
urteen of these patients underwent surgical placement of a temporary i
ntrapelvic tissue expander prior to radiotherapy, and 63 patients did
not. Small bowel volume within the treatment portals was measured for
both initial pelvic and conedown fields for all cases, and compared be
tween the two patient groups. Results: The volume of small bowel withi
n the initial pelvic fields receiving full dose irradiation was signif
icantly less among patients with a tissue expander. For patients with
a tissue expander, mean volume receiving full dose irradiation was 25
cm3 (median 0 cm3, range 0-297 cm3), whereas the corresponding volume
was 239 cm3 (median 181 cm3, range 0-943 cm3) without a tissue expande
r (p < .0001). A similar reduction of irradiated small bowel volume wa
s noted in the conedown fields with the use of a tissue expander (p =
.07). Volumes receiving less than full dose irradiation were also less
within the initial pelvic (p = .0001) and conedown (p = .002) fields
with a tissue expander. Multivariate analysis of patient and treatment
-related parameters showed the use of a tissue expander to be the only
factor correlated with decreased small bowel volume within the treatm
ent field (p = .003). Morbidity related to placement and removal of th
e tissue expander was acceptable. Acute radiation-related morbidity wa
s significantly less in patients irradiated with a tissue expander in
place (p < .001). Conclusions: Placement of an intrapelvic tissue expa
nder was correlated with decreased small bowel volume within the radio
therapy treatment field. Diminished radiation-induced acute gastrointe
stinal morbidity was noted with use of a tissue expander.