ABSTRACT
However, studies on pregnancy outcome in human survivors of cancer treatment indicate that such concerns may be unfounded. Patients exposed to cancer treatment do not appear to have a greater than normal risk of chromosomal or congenital abnormalities78,79,156,157 There are several explanations for this potential discrepancy. First, existing studies may not have sufficient power to detect a small difference. Alternatively, DNA repair mechanisms may be capable of correcting genomic damage during the time between exposure to mutagenic treatment and conception158. A third possibility is that there is a selection bias against genetically abnormal germ cells. It is, therefore, of some concern that techniques of assisted conception bypass the natural selection of healthy germ cells. Frozen semen banking is sometimes offered after the commencement of chemotherapy. If such a sample proves unsuitable for simple insemination, a single sperm may be selected artificially for use in the technique of intracytoplasmic sperm injection. Similarly, oocyte recovery for ART may be initiated in women who have already commenced chemotherapy programs. In animal studies where conception occurred soon after administration of chemotherapy there was a high incidence of malformation, implying damage to the oocytes131. Follicular growth takes several months in humans and it is likely that oocytes exposed to chemotherapy during this time will sustain significant damage. Currently there is no defined period of time after which it is safe to use such oocytes for ART. Long-term follow -up of offspring is required to evaluate this further.
