Is it safe to bank sperm while undergoing cancer treatment?

Sometimes we’ll see a patient who’s been diagnosed with cancer, and cancer therapy has been initiated—be it radiation therapy or chemotherapy—and we know these therapies can have an effect, not only on the cancer within the patient’s body, but in many instances also negatively affects sperm develop within the testicle or maturing in the epididimus. The literature is not really clear on when it’s safe to preserve sperm. For instance, say a patient got only one round of chemotherapy, or one treatment—is it safe in that setting to obtain sperm and freeze it for future use? We really don’t know for sure about the safety of that sperm. Our stance at Northwestern has been, and the stance for most people who are interested in fertility preservation around the country, would be to collect sperm in that setting and freeze it—with the realization being that it may not be your first choice for use down the road in the setting of in vitro fertilization, but at the very least there will be some sperm frozen that could potentially be used.
When I say that the sperm may not be safe in the setting of a patient having received their therapy, what we’re really getting at is that we don’t know what effect the cancer treatment will have on an individual’s sperm. So it is possible that chemotherapy or radiation therapy may damage an individual’s sperm without us being able to really assess the sperm and find out what the degree of damage has been. The bottom line with sperm is that there’s not an adequate way to look at it to assess the DNA damage without destroying the sperm, and so that somewhat limits our ability to sort through a sample of semen and determine which sperm are good and which are bad. But again there are a number of other markers that we can use, such as the motility of the sperm, the overall appearance, the shape of the sperm, that may provide at least some degree of insight into the overall health of an individual’s sperm.

If a sperm’s DNA is damaged, this may negatively affect the ability of a sperm to fertilize an egg and, additionally, if fertilization does occur, it may affect the ability of the subsequent embryo that’s formed to undergo normal development within the female reproductive tract.