Intraoperative sonography in patients with colorectal cancer and resectable liver metastases on preoperative FDG‐PET‐CT

Abstract

Background. Combined fluorine 18-fluorodeoxyglucose-positron emission tomography-CT imaging has been shown to be of good diagnostic value in the preoperative evaluation of patients with colorectal cancer and liver metastases. The adjunctive use of intraoperative sonography (IOUS) may have a limited impact on treatment selection in these patients.Purpose. To compare the diagnostic performance of preoperative positron emission tomography (PET)-CT alone and PET-CT combined with IOUS in the evaluation of patients who are considered for curative resection of hepatic metastases from colorectal carcinoma.Materials and Methods. Patients with colorectal cancer who underwent resection of hepatic metastases and preoperative PET-CT (with or without contrast-enhanced CT) and IOUS were identified. The performance of the imaging techniques was evaluated through review of the radiologic reports, correlation with surgical and histopathologic findings, and clinical follow-up.Results. Thirty-one patients (mean age, 63.5 years [range, 53-82 years]) were analyzed. Fifteen patients had received preoperative chemotherapy. The mean interval between PET-CT and IOUS was 22.6 days (range, 1-56 days). In 4 cases, neither PET-CT nor IOUS correctly diagnosed the liver metastases. In all 31 patients, the sensitivity of PET-CT alone and PET-CT combined with IOUS was 63% (95% CI 44-80%) and 93% (95% CI 78-98%), respectively; the positive predictive value was 81% and 89%, respectively. In patients without preoperative chemotherapy (n 5 16), the sensitivity of PET-CT alone and PET-CT combined with IOUS was 77% (95% CI 49-94%) and 100% (95% CI 79-100%), respectively. In 11 cases (35%), IOUS altered the surgical strategy.Conclusion. In patients with colorectal carcinoma and potentially resectable liver metastases on preoperative PET-CT, IOUS can provide additional information that may alter decision making with regard to surgical technique. Keywords: colorectal cancer; liver metastases; intraoperative sonography; FDG-PET-CT C olorectal cancer is the second leading cause of cancer-related death in the western hemisphere. Up to 70% of patients with colorectal cancer eventually develop liver metastases. In 30-40% of these patients, metastases are confined to the liver at the time of detection. Hepatic resection is the only therapeutic strategy that offers a chance of cure. In patients who undergo successful hepatic resection with curative intent, the expected 5-year survival rate is approximately 33%, and the 5-year disease-free survival rate is 22%. 1 A large number of patients develop intraor extrahepatic tumor recurrence after curative

The value of FDG positron emission tomography/computerised tomography (PET/CT) in pre-operative staging of colorectal cancer: a systematic review and economic evaluation.

“…Sixteen studies 24,62,63,[68][69][70][71][79][80][81][82][83][84][85][86][87] evaluating the diagnostic test accuracy of combined functional and anatomical imaging with FDG PET/CT for the detection of colorectal metastases were identified. The majority of the studies identified investigated metastatic disease to the liver.…”

“…The majority of studies used a retrospective design, 24,62,63,68,71,79,80,82,85,86 with only five studies using a prospective design 70,81,83,84,87 and one being unclear whether the study was retrospective or prospective. 69 The majority of reports did not reveal the manner in which sample patients were recruited; only six reported taking a consecutive approach 24,62,83,84,86,87 and one 82 reported that the sample was not recruited consecutively.…”

“…In 13 studies, 62,63,[68][69][70][79][80][81][82][83][84][85]87 patients were indicated for an FDG PET/CT scan when hepatic metastases were suspected from other follow-up examinations, imaging tests and blood tests. In three studies, 62,63,68 patients were investigated for a recurrence of CRC, but metastatic disease was detected.…”

“…In some studies patients received either oral 68,69,84 or intravenous 63,[83][84][85] contrast agents with the CT component of the FDG PET/CT test.…”

“…Some studies 24,68,82,83 also used a qualitative judgement scoring grade [using scores of 0 to equate to no lesion, 1 = definitely benign, 2 = probably benign, 3 = possibly benign, 4 = possibly malignant, 5 = probably malignant, 6 = definitely malignant (1-3 benign, 4-6 malignant)], while others used focal increased FDG uptake compared with background lesions. 63,69,79,84,85,87 Only one study 71 reported using SUV max in the assessment of FDG PET/CT images. Lesions with a SUV max of > 2.5 in the early imaging and a change in the SUV max of > 20% in the delayed imaging were considered positive.…”