As treatments for childhood cancers have improved, more and more survivors are entering their reproductive years, and are thinking about starting families of their own. Unfortunately, impaired fertility can be an unwanted consequence of the treatments used to cure pediatric cancer. The Cancer Survivorship Program team at The Children's Hospital of Philadelphia recognizes that fertility is an extremely important issue related to long-term quality of life for our survivors. Thought must be given to whether a child's fertility is likely to be impacted by treatment. Ideally, this should occur before the start of therapy, when a window of opportunity may exist to preserve the patient's future reproductive potential.
The Cancer Survivorship Program is very invested in offering fertility preservation options to the patients and families who are seen in Oncology. At this time, within the context of multiple organized research efforts, we are pleased to be able to offer fertility preservation options to pre-pubertal and pubertal males and females.
Fertile Hope is a national, nonprofit organization dedicated to providing reproductive information, support and hope to cancer patients and survivors whose medical treatments present the risk of infertility. In January 2009, Fertile Hope named CHOP a Center of Excellence for its commitment to inform all cancer patients and their families of the infertility risk of cancer treatment and to offer potential ways to preserve fertility. We are the first children's hospital to achieve this distinction.
For males who have reached puberty, freezing sperm at diagnosis is the gold standard for fertility preservation and it has a well-demonstrated success rate. A research study was completed by our team on a group of patients who were approached to sperm bank at CHOP between 2002 and 2006. The study examined both the semen quality of banked specimens and the beliefs and decision-making processes of adolescents and young adults who attempted to bank or considered it. The results gleaned from this study now provide the cornerstone of our clinical practice standards for sperm banking. We recommend that sperm banking be offered to all eligible patients (defined as any male newly diagnosed with cancer who has reached puberty). We work closely with the healthcare team to ensure that sperm banking is integrated into the patient and family education of newly diagnosed males. Our team facilitates this process by discussing sperm banking with families and by helping families to make appointments at a local reproductive endocrinology practice.
While preserving fertility is an important topic for families to discuss before cancer treatment begins, it can also lead to some uncomfortable conversations. In this video, former CHOP cancer patients discuss why they made the decision to bank their sperm, and describe what the experience was like for them.
Unlike pubertal boys, prepubertal males pose a particular challenge for fertility preservation. These boys cannot produce semen for cryopreservation by masturbation and they do not yet have mature sperm. The prepubertal testicle does, however, contain a small amount of the stem cells (parent cells) that, with the right signals, will eventually become mature sperm. Promising research with animals in the lab has shown that testicular tissue can be removed and these stem cells, although few in numbers, can be extracted. These cells can then be reimplanted as is or matured and increased in number outside of the body before reimplantation. At this time, clinical applications of this science in humans are purely experimental. However, research is currently underway at CHOP that allows prepubertal boys to have a testicular biopsy at diagnosis and freeze the tissue for their potential future use. A small piece of the tissue is also being studied in the laboratory to help scientists determine how the germ cells in the testicular tissue should be handled so that the maximum number of sperm-creating cells can be obtained. Parents have indicated that they welcome an opportunity to potentially preserve their son's fertility, even if the science does not currently exist to use the tissue for this purpose.
We have developed a clinical and research partnership with Penn Fertility Care and Main Line Fertility to offer both egg and embryo freezing to our patients. While not an option for all of our females, there are opportunities to pursue this option when the patient's circumstances will allow. Hormones are used to stimulate the formation of multiple egg follicles. These eggs are then removed and are frozen for the patient's potential future use to achieve a pregnancy. This method is becoming more and more widely accepted, and there have been hundreds of live births from frozen eggs. In a circumstance where the patient may have a partner, there is also the option of using the eggs to create an embryo, which can then be frozen for future use.
Embryo freezing and oocyte freezing require ovarian stimulation at diagnosis and are not appropriate for prepubertal girls or when delaying cancer therapy is not an option. An alternative approach is the cryopreservation (freezing) of ovarian tissue. This tissue can then be thawed and reimplanted at a later date, thereby restoring ovarian function. While still experimental, ovarian tissue cryopreservation is beginning to show promise as a viable clinical option. Successful live births have been achieved in humans using frozen ovarian tissue, although the numbers are very small. As part of a research protocol at CHOP, we can now offer ovarian tissue cryopreservation to girls as young as 10 years of age who are at risk for infertility from their cancer therapy. As part of this study, a small portion of the ovary is surgically removed before starting cancer therapy. Eighty percent of the tissue is frozen and stored for the participant's own use in the future. The remainder of the ovarian tissue is used by researchers to explore ways to extract immature eggs from the tissue and mature them in the laboratory.