When the physician sees the clinical signs of choriocarcinoma, also known as “gestational trophoblastic disease”, he orders beta HCG levels. In particular, if this test is positive, he wants further diagnostic tests and requires staging of the choriocarcinoma.
For one thing, if the beta HCG levels are high, the physician will refer the patient to a gynecologist with experience in this field. The specialist orders other tests such as an ultrasound of the pelvis, the uterus and the ovaries. In the past amniography was done, which showed a “moth-eaten” pattern typical for the disease, but this is no longer an up-to-date test.
However, with other test methods (CT and MRI scan) and the more sophisticated high resolution ultrasonography the specialist more likely orders these other tests . The specialist in the field will order the appropriate tests. Dependant on the clinical situation there may be other tests that the specialist requires to look for distant metastases.
Staging
Equally important, like with other cancers it is important to establish the exact nature of the gestational trophoblastic disease. To clarify, questions like these have to be answered: explicitly, is it benign or malignant disease, in other words is it a hydatiform mole, which is benign, is it the less serious locally invasive mole, or is it choriocarcinoma, which is aggressive? In this case, is it still contained in the uterus, has it spread locally or possibly into the blood stream and into the rest of the body? Generally speaking, all these questions are answered so that different treatment decisions can be made. In the final analysis, a mistake in the beginning, like an overlooked distant metastasis, can cost the woman her life!
Here is an overview of the staging for trophoblastic disease:
Staging of gestational trophoblastic disease *
| Stage: | Type of disease: | Description of extent: |
| 0 A | low risk molar pregnancy | no infiltration of uterus |
| 0 B | high risk molar pregnancy | may start to invade uterus |
| I | locally invasive mole | confined to uterus |
| II | choriocarcinoma | local metastases to vagina and pelvis |
| III | choriocarcinoma | lung metastases |
| IV | choriocarcinoma | distant metastases |
* New England Trophoblastic Disease Center staging classification
Notably, as can be seen from the table, the staging depends on the spread of the gestational trophoblastic disease. Certainly, this can be determined using the tests mentioned above in combination with a thorough history and gynecological examination.
Generally speaking, the total tumor load depends on how much of the trophoblastic tissue is present within the body. On balance, the concentration of the beta-HCG in the blood stream (high versus low levels) accurately reflects whether there is a lot or very little total tumor tissue present in the body. By and large, this has improved the cancer survival rates dramatically in the past few decades, particularly in the earlier stages, as the physician has now a means of defining the end point of treatment. It must be remembered that as long as the very specific beta-HCG blood test is positive, the treatment must go on and may have to be stepped up until a cancer cure has been achieved.
References
1. Cancer: Principles &Practice of Oncology.4th edition. Edited by Vincent T. DeVita, Jr. et al. Lippincott, Philadelphia,PA, 1993. Vol. 1. Chapter on gynecological tumors.
2. Cancer: Principles&Practice of Oncology. 5th edition, volume 1. Edited by Vincent T. DeVita, Jr. et al. Lippincott-Raven Publ., Philadelphia,PA, 1997. Chapter on gynecological tumors.
3. Kohorn Int J Gynecol Cancer 2001 EI John 11 (1) :73-77.
4. MS Cha et al. Biochem Biophys Res Commun 2001 Sep 13; 282 (4) :1061-1066.
5. El-Lamie IK et al. Int J Gynecol Cancer 2000 Nov; 10 (6) :488-496.
6. AM Case et al. Hum Reprod 2001 Feb; 16 (2) :360-364.
