First, to evaluate the causes of choriocarcinoma we need to first be aware that there are countries in the world where this disease is more common than in others. In brief, the U.S. is one of the countries where choriocarcinoma is less common (about 1 in 1200 pregnancies). In contrast, in South America and Asia the rate is about 1 in 120 pregnancies, in other words 10-fold more common.
Second, it was found in a study in the Philippines that those people who are meat eating and who are wealthier have a much lower rate of this disease than those who are rice eating.
Choriocarcinoma more common in older women
On the other hand, the risk for choriocarcinoma increases with age (woman above 40 or 45), as much as 10- to 12-fold compared to younger women (age group of mid twenties). For one thing, about 50% of trophoblastic tumors follow a pregnancy. They can develop after a pregnancy, a tubal pregnancy or a miscarriage. The other 50% develop out of a molar pregnancy. In this case, it looks initially like a regular pregnancy in that the woman does not have a period and develops an enlarged uterus. However, the uterine enlargement within the first 10 to 16 weeks after conception is very rapid and, in particular, ultrasonography fails to show any fetal parts.
Hydatiform mole rapidly deteriorates into choriocarcinoma
With this in mind, the uterus contains only the abnormally formed placenta-like tissue called “hydatiform mole”. In fact, this is still a benign tumor formation (see above). But it will rapidly deteriorate and, if left alone will become a choriocarcinoma. To clarify, there is only a short window of opportunity to quickly evacuate this tissue. About 15% of patients after a molar pregnancy develop a locally invasive mole and if this is left alone, choriocarcinoma develops with metastases through the blood stream. In detail, this is a tumor with a large amount of blood vessels; for this reason it metastasizes early. Any such case needs urgent attention by a gynecologist.
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. EI Kohorn Int J Gynecol Cancer 2001 Jan;11(1):73-77.
4. MS Cha et al. Biochem Biophys Res Commun 2001 Apr 13;282(4):1061-1066.
5. IK El-Lamie 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.
