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THE
ROLE OF ENDORECTAL ULTRASONOGRAPHY IN THE PREOPERATIVE EVALUATION
OF RECTAL CANCER
Radovanović
Z, Petrović T, Ađić O, Prvulović M.
Institute
of Oncology Sremska Kamenica, Sremska Kamenica, Serbia
and Montenegro
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ABSTRACT
Endorectal
ultrasonography (ERUS) is valuable method for accurate local staging
of rectal cancer. Precise evaluation of tumor stage is essential
for optimal therapy planning in patients with rectal cancer. Furthermore
it has great influence on the resectability and the risk of recurrence
following resection. ERUS has become the most common diagnostic
tool for locally staging rectal cancer due to its advantages over
MRI and CT. Among these diagnostic modalities ERUS has been known
to be most accurate. A careful review of the literature reveals
that accuracy of T- and N-staging with ERUS ranges from 67 to 94%
(the majority reporting in the 80% to 90% range) for tumor depth
and from 64% to 84% for nodal involvement. Moreover, ERUS is inexpensive
and quick diagnostic procedure associated with minimal discomfort
to the patient. However, the use of CT, MRI and more recently magnetic
resonance imaging with endorectal coil (MRIEC) often remains necessary.
These modalities may be useful supplements in patients with suspected
T4 lesion, when ERUS is technically unsuccessful and in cases of
diagnostic dilemma. The possibility for over- and downstaging during
ERUS must be kept in mind. The main reasons for overstaging tumor
depth invasion are inflammatory and associated reactive changes
in rectal wall and perirectal tissue and preoperative radiotherapy.
In stenotic cancers optimum positioning of the ultrasound probe
can be difficult with possible understaging of the depth of tumor
invasion. The overstaging of lymph node status is primary caused
by the presence of reactive swollen lymph nodes, while difficulty
in detecting very small involved nodes (less than 2 mm) is main
reason for understaging. In the last decade, major improvements
in diagnostic and staging of rectal cancer have led to stage-oriented
surgery, planning of therapy individually for each patient, reduce
of local recurrences and better overall survival. This article reviews
the current use of ERUS in preoperative staging of rectal cancer
as the most practical and accurate diagnostic modality for preoperative
locoregional staging of rectal cancer at this time.
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Keywords:
Endorectal ultrasonography, Rectal cancer, Staging |
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