Fig. 3 demonstrates the time course of serum hGH-V and hCG in
a case of surgical treatment with an uneventful follow-up (complete
hydatidiform mole).
hGH-V drops below detection limit on the day of surgery, whereas
hCG is still detectable in a large amount in accordance with its 300
fold higher initial half-life on the first days following surgery.
In clinical routine, hCG analysis until its drop belowdetection limit is
mandatory, thus making follow-up visits with additional costs and effort
for the patient necessary.
Larger studies are required to investigate, whether hGH-V is a reliable
marker to monitor and document the complete removal of the
GTDtissue aswell as its possible recurrence. Reducing the financial, psychological
and physical burden of the hCG-follow-up visits are of great
importance.
Fig. 4 depicts the time course for a case of medical treatment of
choriocarcinoma with pulmonal metastases receiving multi agent chemotherapy
(EMA/CO: etoposide, methotrexate and actinomycin D
alternating with cyclophosphamide and vincristine). After a drop in
both serum hGH-V and hCG (the former below detection level) after
starting chemotherapy, therewas a secondary rise despite chemotherapy
and the patient died due to respiratory failure as a result of progression
of the disease. The initial rise of hCG after starting treatment is a
known characteristic also being observed in the medical treatment of
ectopic pregnancy with methotrexate.
Apparently the levels of hCG and hGH-V detected in the patient's
blood in different entities of GTD seems to be variable. In the presented
case of CHM (Fig. 3) serum levels of hCG compared to hGH-V are much
lower than in the presented case of CCA (Fig. 4). It is tempting to speculatewhether
a hCG/hGH-V ratio could be of use in determining the biological
characteristics of the type of GTD in clinical routine.
Both cases demonstrate the possible role of hGH-V as a biomarker
in GTD. Further data is required to determine its clinical utility especially
due to its short serum half-life. In this contextwe like to stress the point
that in four of sixteen cases hGH-V was not detectable in the serum despite
its presence in IHC in all samples analyzed.
A limiting factor for further studies is the low incidence of GTD and
the ubiquitous available, well-established marker hCG.