Intraoperative ultrasound imaging of the liver at the time of colorectal cancer resection
M. D. Stone, R. Kane, A. Bothe Jr, J. M. Jessup, B. Cady and G. D. Steele Jr
Division of Surgical Oncology, New England Deaconess Hospital, Harvard Medical School, Boston, Mass.
OBJECTIVES: To evaluate the accuracy of intraoperative ultrasound (IOUS)
liver imaging at the time of primary colorectal cancer resection, which
might eliminate incurable patients from adjuvant chemotherapy trials or
permit earlier resection of curable metastases. DESIGN: A prospective trial
of routine IOUS liver imaging during resections of primary colorectal
cancer. The rate of detection of occult metastases by IOUS imaging alone
and the false-negative rate over 22.7 months of follow-up were determined.
SETTING: A tertiary care referral center in Boston, Mass. PATIENTS:
Fifty-five patients undergoing 56 operations for colorectal carcinoma
between May 1990 and June 1992. MAIN OUTCOME MEASURES: The rate of
detection, by IOUS imaging alone, of otherwise occult hepatic metastases,
the total number of patients with metastases detected at any time during
follow-up, and the rate of false-negative findings on IOUS imaging and
direct examination. RESULTS: Occult hepatic metastases were detected by
IOUS imaging alone in 5% of patients. Restriction of IOUS imaging to
patients with T3 or T4 lesions or recurrent cancers would have identified
all metastases and increased the detection rate to 10%. Occult metastases
were detected by IOUS imaging alone in 12.5% of patients with T3, N0
lesions. The rate of false-negative findings on IOUS imaging was 13%
overall, 0% for patients with T1 or T2 lesions, 3% for patients with
node-negative findings, and 7% for patients with T3, N0 lesions.
CONCLUSIONS: The small increment in the detection of occult metastases by
IOUS liver imaging does not warrant its use in all patients with colorectal
cancer. Selective use in patients with T3 or T4 lesions or recurrent
cancers increased the incremental gain in detection. The observed frequency
of occult metastases in patients with T3, N0 lesions is sufficient to
impact on results of adjuvant chemotherapy trials. Longer follow-up in more
patients is needed to determine whether a negative IOUS study is an
additional favorable prognosticator in patients with T1 and T2 lesions and
node-negative findings.
