Report on various clinical studies on high dose methotrexate in Europe (non EORTC).

High dose Methotrexate (HDMtx) is used in the therapy of a broad variety of human tumors. This review reports on completed, ongoing, or planned clinical trials or experience with HDMtx in individual therapy modalities. It is stressed that HDMtx-therapy should solely be given by highly skilled and experienced clinical oncologists, who are able to prevent toxicity and unnecessary side effects by determining Mtx-serum-levels, urine pH, fluid balance and detect clinical indicators for toxicity early enough to escape fatal organ damages.