Germ cell tumors and germ cell tumors are 2 different concepts. Germ cell tumors are only one type of germ cell tumor and can account for about half of germ cell tumors. Germ cell tumors also include diseases such as embryonal carcinoma, teratoma, and choriocarcinoma.
Germ cell tumors mostly occur in the midline areas of the body, and are more common in the pineal region, thalamus, hypothalamus, pituitary stalk, and other areas. Among them, pineal region and saddle region are the most common. However, there are other tumors in the pineal and saddle areas. For example, germ cell tumors, tumors of glial cell origin, tumors of pineal cell origin, and other rare tumors such as meningiomas can occur in the pineal region.
Germ cell tumors have their biological indicators in blood and cerebrospinal fluid tests, and usually require both blood and cerebrospinal fluid tests for human chorionic gonadotropin (HCG), alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA). These indicators can help in differential diagnosis and also guide treatment. Also MRI of the head is an important indicator to help diagnose and guide treatment.
In the past, because of the deep location of germ cell tumors and the fact that most of them are sensitive to radiotherapy, experimental radiotherapy was mostly chosen. However, different opinions have been formed abroad regarding the treatment of this disease.
For germ cell tumors, if the AFP and HCG are greater than 50, we can consider that the AFP and HCG are positive and surgery is preferred. If the AFP and HCG are relatively low and negative, surgery is also recommended as the first choice of treatment if there is inhomogeneous enhancement, calcification or cystic changes on MRI. Experimental radiotherapy is only recommended if there is homogeneous enhancement and both AFP and HCG are negative. 20 CGY is usually given first and surgery is recommended if it is not effective.
At present, there are different opinions abroad for germ cell tumors that are sensitive to radiotherapy. The main reason is that radiotherapy leads to more serious complications of radiotherapy while controlling the tumor, mainly intellectual problems and neuroendocrine problems, and the patient develops intellectual decline and developmental arrest with total pituitary function, therefore, for germ cell tumors, chemotherapy is beginning to be recommended as the first choice abroad. However, the current cure rate of chemotherapy is around 65%, which still does not reach the effect of high-dose radiation therapy, which is around 85%, and is therefore still in the research phase.
The current consensus is that if the tumor is larger than 2 cm, surgery is recommended as the first choice.
The most important reason that hinders surgery is the perioperative death and disability rate, which is reported abroad as 0%-8% mortality and 0%-25% severe disability. The occurrence of surgical complications depends on the type of tumor and the operator’s experience and microscopic technique. In general, pineoblastoma has the highest mortality and disability rate. Because the tumor is tough and rich in blood supply is the most important reason that makes the surgery more difficult.
At present, based on the MRI film, we assess the surgical risk and decide the surgical approach based on four aspects: surgical access, tumor texture, tumor blood supply and tumor encirclement of the internal cerebral vein, and have achieved better surgical results.
From our current experience, patients who choose surgery based on MRI and biological indices have tumors that are mostly mixed, i.e., teratomas that contain a small amount of germ cell tumor and yolk sac carcinoma components, and a small percentage of other germ cell tumors.
Therefore, as doctors must tell, the choice of treatment for germ cell tumors is very important, and the standard treatment is likely to be surgery, followed by chemotherapy and then radiation therapy. But because surgery is risky and traumatic, many patients choose to go straight to radiotherapy. Maybe the patient does have pure germ cell tumor or pineal cell tumor combined with lymphocytic infiltration, then you have chosen the right choice. But many patients may be in a more embarrassing situation and the next step of treatment is very difficult.