Whole-body PET imaging with [18F]fluorodeoxyglucose in management of recurrent colorectal cancer.

HYPOTHESIS: Metabolic imaging by positron emission tomography (PET) using [18F]fluorodeoxyglucose will be more accurate than anatomic imaging by computed tomography (CT) for detection of recurrent colorectal cancer. More accurate staging of recurrent tumor by PET will lead to more appropriate management decisions. DESIGN: Prospective blinded study comparing PET with CT, using histologic diagnosis, serial CT imaging, and clinical follow-up as criterion standards, with a fully blinded, retrospective reinterpretation of PET studies. Changes in diagnosis resulting from PET findings were correlated with subsequent treatment and surgical findings. Potential cost savings resulting from use of PET for preoperative staging were calculated. SETTING: Private practice in an outpatient tertiary referral center. PATIENTS: A group of 155 consecutive patients with imaging for diagnosis or staging of recurrent colorectal cancer. Twenty-one patient (14%) were excluded due to lack of a criterion standard. Computed tomographic scans were available for comparison for 115 patients. RESULTS: Positron emission tomographic scan sensitivity and specificity were 93% and 98%, respectively, compared with 69% and 96% for CT. Ninety-five percent confidence intervals for the differences between the modalities were 16% to 32% for sensitivity and 1% to 5% for specificity. The sensitivity of both modalities varied with anatomic site of recurrence. Positron emission tomographic scans were true positive in 12 (67%) of 18 patients with elevated serum carcinoembryonic antigen levels and negative CT findings. In 23 (29%) of 78 preoperative studies in which CT showed a single site of recurrence, PET showed tumor at additional sites. At surgery, nonresectable, PET-negative tumor was found in 7 (17%) of 42 patients who had PET evidence of localized recurrence only. Potential savings resulting from demonstration of nonresectable tumor by PET were calculated at $3003 per preoperative study. CONCLUSIONS: Positron emission tomography was more sensitive and specific than CT for detection of recurrent colorectal cancer. Preoperative detection of nonresectable tumor by PET may avoid unnecessary surgery, and thereby reduce the cost of patient treatment.

Cost-effectiveness of PET imaging in clinical oncology.

To be cost-effective, PET must be diagnostically accurate and effective in improving management without increasing treatment cost. To evaluate diagnostic accuracy, we performed prospective evaluations of whole-body PET imaging in staging of non-small-cell lung cancer (99 patients), detection of recurrent colorectal cancer (57 patients), diagnosis of metastatic melanoma (36 patients), and staging of advanced head and neck cancer (29 patients). In each case, PET was more accurate than anatomic imaging for determination of the presence and extent of tumor and demonstration of nonresectable disease. PET was also more accurate than conventional imaging in staging Hodgkin's disease (30 patients). We evaluated the management impact of PET retrospectively, by reviewing the treatment records of 72 patients with solitary pulmonary nodules or non-small-cell lung cancer, 68 patients with known or suspected recurrent colorectal cancer, 45 patients with known or suspected metastatic melanoma, and 29 patients with advanced head and neck tumors. PET improved patient management by avoiding surgery for nonresectable tumor and for CT abnormalities that proved to be benign by PET imaging. For determining cost impact, the costs of surgical procedures were determined from Medicare reimbursement rates, and the cost of a PET study was taken to be $1800. The savings from contraindicated surgical procedures exceeded the cost of PET imaging by ratios of 2:1 to 4:1, depending on the indication. PET was decisively more accurate and cost-effective than anatomic imaging by CT, combining improved patient care with reduced cost of management.