The influence of CA 125 and CEA levels on the results of (18)F-deoxyglucose positron emission tomography in suspected recurrence of epithelial ovarian cancer.

BACKGROUND AND PURPOSE: The follow-up of epithelial ovarian cancer (OCA) consists of clinical investigation, sonography, and tumor markers (TMs), especially CA 125. If tumor recurrence is suspected, other imaging modalities including positron emission tomography (PET) with (18)F-deoxyglucose (FDG) are often used. While there is still no consensus about the method of choice and the timing of its application, this study aims to find a TM threshold at which a PET would be appropriate. MATERIAL AND METHODS: A total of 90 PET studies and the associated CA 125 values (normal value < 35 U/ml) were available in 71 patients during the follow-up after primary therapy for OCA. In 48 studies a CEA value (normal value < 3 ng/ml) was also available. The results of PET imaging were related to the level of TM increase. RESULTS: In 23/90 studies the PET scan was normal. These patients had a median CA 125 of 13.3 U/ml (range 4.2-168 U/ml). In 67/90 studies the PET indicated a potential recurrence of OCA and the median CA 125 was 166.7 U/ml (range 13.3-4,060 U/ml). The TM levels were significantly different (p < 0.001, U-test). With one exception, there were no normal PET scans above CA 125 levels of 30 U/ml; between 20 and 30 U/ml PET was positive in 4/7 studies. CONCLUSION: In suspected recurrence of OCA, if imaging modalities are to be used, an FDG PET may be considered. Since the costs of this investigation are high, it should be restricted to clinical situations where it is likely to be most effective. In this study a PET indication is worthwhile at CA 125 levels of approximately 30 U/ml.

Positron emission tomography in patients with Hodgkin's disease: correlation to histopathologic subtypes.

The aim of this study was to evaluate the initial staging and restaging of Hodgkin's disease (HD) according to histopathologic subtype (HST) using fluorine-18-deoxyglucose-positron emission tomography (PET). Special attention was paid to the accuracy of PET for detection of bone marrow infiltration (BMI). 44 patients with HD (m:f = 28:16, mean age 36 +/- 15 years) underwent PET; 16 were primary stagings and 28 restaging examinations. PET results were compared with methods of conventional staging including computed tomography (CT) and bone marrow biopsy. Viable tumor tissue was detected by PET in 25/44 cases, 16 nodular sclerosis (NS), 4 mixed cellularity (MC), 3 lymphocyte predominance (LP) and 2 cases with a nonclassified subtype (NC). FDG tumor uptake, measured as standard uptake value (SUV), ranged from 1.7 to 13. Maximum SUV in NS was 5.2 +/- 1.5 (2.5-7.3), 3.2 +/- 2.4 for MC, 2.6 +/- 0.7 for LP, and 9.1 +/- 3.8 for NC, respectively. In 7% of all patients (3/44) bone marrow infiltrations were detected by PET. PET is known for its superior detection of viable tissue in HD. In this study it was shown that HST does not influence the intensity of glucose metabolism, although 2 patients with NC showed the highest SUVs. In addition PET accurately detected focal BMI and may thus be applied before BMB to guide its optimal use.