Abstract | OBJECTIVES: METHODS: Data collected on cases referred to the USA hCG Reference Service for consultation served as a basis for this retrospective analysis. There were 13 cases with histology proven PSTT and 12 with nontrophoblastic malignancy. hCG-free beta-subunit was measured by immunoassay and reported as a proportion of total hCG (hCG-free beta-subunit(%)). hCG-free beta-subunit(%) results were determined for all histologically proven cases of PSTT and for the nontrophoblastic malignancies. Comparisons of hCG-free beta-subunit(%) were made and compared with those of the 82 choriocarcinoma/GTN cases and 69 quiescent GTD cases. The accuracy of hCG-free beta-subunit(%) to discriminate these malignancies was analyzed by investigating the areas under receiver-operating characteristics curve +/- standard error. RESULTS: hCG-free beta-subunit(%) was the predominant hCG form in cases of PSTT (mean +/- standard deviation, 60 +/- 19%) and nontrophoblastic malignancies (91 +/- 11%), thus discriminating these diagnoses from choriocarcinoma/GTN (9.3 +/- 9.2%) and from quiescent GTD (5.4 +/- 7.8%). The cutoff of >35% free beta-subunit is proposed. At this cutoff, 100% detection at 0% false-positive is achieved. The accuracy of hCG-free beta-subunit(%) for this discrimination is 100 +/- 0%. At a proposed cutoff of >80%, the free beta-subunit test will also distinguish PSTT from nontrophoblastic malignancy, with 77% detection at 23% false-positive or an accuracy of 92 +/- 3.2%. CONCLUSION: Measurement of the proportion hCG-free beta-subunit(%) was found to be useful in the diagnosis of PSTT using proposed cutoff values of >35% and >80%. While this finding needs to be confirmed by larger studies, it would be reasonable to measure hCG-free beta-subunit(%) whenever the diagnosis of PSTT is considered.
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Authors | Laurence A Cole, Sarah A Khanlian, Carolyn Y Muller, Almareena Giddings, Ernest Kohorn, Ross Berkowitz |
Journal | Gynecologic oncology
(Gynecol Oncol)
Vol. 102
Issue 2
Pg. 160-4
(Aug 2006)
ISSN: 0090-8258 [Print] United States |
PMID | 16631918
(Publication Type: Journal Article)
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Chemical References |
- Chorionic Gonadotropin, beta Subunit, Human
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Topics |
- Choriocarcinoma
(blood, diagnosis)
- Chorionic Gonadotropin, beta Subunit, Human
(blood)
- Diagnosis, Differential
- Female
- Gestational Trophoblastic Disease
(blood, diagnosis)
- Humans
- Pregnancy
- Trophoblastic Tumor, Placental Site
(blood, diagnosis)
- Uterine Neoplasms
(blood, diagnosis)
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