Fertility preservation in male patients subjected to chemotherapy; innovative approaches for further progress.

About 4% of male patients with cancer are under the age of 35 years. With the current increase in efficacy and safety of therapies, a growing number of young adults can achieve long-term survival. In male patients receiving systemic chemotherapy and or bone marrow transplantation, a permanent loss of fertility is a common adverse effect. The only possibility to preserve the patient's fertility is to spare the gametes or gamete-forming cells from the chemotherapeutic effect. In adults, this can be achieved by the cryopreservation of spermatozoa with the subsequent application of assisted reproductive technology. Sperm cryopreservation is currently performed using slow-rate cryopreservation as a standard method, in which sperm cells are incubated with a cryoprotective medium and slowly subjected to hypothermia in liquid nitrogen (LN) vapor before they are placed in LN. Another technique called vitrification relies on the direct placement of the cells into LN, after being suspended in a vitrification medium. Many studies compared the clinical outcomes of both techniques and revealed equivalent results. This paper sheds light on some innovative approaches for further progress.