GTN is a cancer that most often arises after a molar pregnancy but can arise after any type of pregnancy. Molar pregnancies occur due to abnormal growth of placental tissue that is usually benign and treated by evacuation of the womb (D&C). However, in less than 10% of molar pregnancies in the UK, the growth remains after D&C and transforms into a cancer (GTN) that needs treatment with anti-cancer drugs (chemotherapy). GTN can be low-risk or high-risk. Anti-cancer drugs are very effective, especially in low-risk GTN, which is usually cured with single-drug treatment. However, high-risk GTN needs to be treated with combinations of anti-cancer drugs for the best effect. These drugs can produce toxic side effects that are more likely to occur when used in combination with each other. The most commonly administered drug combination is abbreviated as EMA/CO, which stands for Etoposide, Methotrexate, Actinomycin D, Cyclophosphamide and Oncovin® (vincristine), but several other combinations are also in use.
We undertook this review to try to determine which combination/s of drugs are the most effective for the first-line drug treatment of high-risk GTN, and with the least side effects. We found only one small, older study that compared a drug combination abbreviated as CHAMOCA with one called MAC. The CHAMOCA regimen, which is no longer recommended for GTN treatment, was found to be extremely toxic to the blood and bone marrow, with no greater effect against the cancer than the MAC regimen. Based on the available evidence, it is currently not possible to determine whether EMA/CO is the most effective and least toxic drug combination as no high-quality studies have been conducted comparing this combination with other combinations. GTN is a rare cancer and so studies in this field are difficult to conduct, therefore researchers need to collaborate in order to produce the necessary high-quality evidence.