Effectiveness of positron emission tomography for predicting chemotherapy response in colorectal cancer liver metastases.
OBJECTIVE
Chemotherapeutic agents may be able to convert unresectable colorectal hepatic metastasis to resectable disease, therefore changing the surgical options. The role of positron emission tomography (PET) for patients undergoing chemotherapy remains unclear. We hypothesize that recent chemotherapy treatment could result in false-negative PET results.


METHODS
Case-control study evaluating PET findings.


METHODS
The University of Texas M. D. Anderson Cancer Center.


METHODS
From May 1, 2006, through August 31, 2008, data for 224 consecutive patients were entered into a prospective database for evaluation of hepatic metastasis of colorectal carcinoma. One hundred thirty-eight patients underwent PET and conventional imaging (a combination of computed tomography, magnetic resonance imaging, and ultrasonography). All had oncologically sound colorectal operations.


METHODS
Liver resection or ablation for colorectal liver metastases.


METHODS
To determine the accuracy of PET scans to detect residual viable colorectal cancer liver metastases after a significant response to systemic chemotherapy.


RESULTS
Patients with biopsy-proven disease underwent hepatic resection (120 patients [87.0%]), radiofrequency ablation (2 [1.4%]), or resection with radiofrequency ablation (7 [5.1%]). Nine patients (6.5%) had inoperable disease that was found intraoperatively. When performed within 4 weeks of chemotherapy, PET had a negative predictive value of 13.3% and a positive predictive value of 94.3%. The sensitivity was 89.9%, the specificity was 22.2%, and the accuracy was 85.5%.


CONCLUSIONS
Positron emission tomography within 4 weeks of chemotherapy is not a useful test for evaluation of colorectal hepatic metastases. The high rate of false-negative results is likely due to metabolic inhibition caused by chemotherapeutic drugs. We recommend that physicians not use PET in patients recently completing chemotherapy; they should undergo the appropriate oncologic hepatic operation based on the high probability of viable malignant disease.
Glazer
Evan S
ES
Department of Surgical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, 77030, USA.
Beaty
Karen
K
Abdalla
Eddie K
EK
Vauthey
J Nicolas
JN
Curley
Steven A
SA
D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D005188:False Negative Reactions; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000556:secondary / Q000601:surgery; D008279:Magnetic Resonance Imaging; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome