The good news is that more children survive cancer now than ever before, with doctors able to cure nearly 80 percent of patients. But that doesn’t mean that kids who survive cancer stop fighting once their treatment ends, because many face a variety of physical and emotional challenges as a result of their treatment.
One of these is the possibility of infertility following cancer treatment, which can be especially worrisome for families of prepubescent boys. While postpubescent boys can bank sperm, and girls of all ages can freeze their eggs, prepubescent boys facing cancer treatment have few fertility preservation options. An estimated 35 percent of prepubescent boys are at risk of sterility following cancer treatment, says Jill P. Ginsberg, MD, director of CHOP’s Cancer Survivorship Program.
Along with CHOP’s Thomas F. Kolon, MD, Dr. Ginsberg has been leading an experimental program that seeks to collect and preserve testicular tissue from young boys who are set to receive cancer treatment, in the hope that the tissue could be used to produce viable sperm. The testicular tissue cryopreservation (TTCP) program offers families hope that their sons might some day be able to have children of their own.
Based on work by the University of Pennsylvania’s Ralph L. Brinster, PhD, the procedure involves the removal of a small amount of tissue containing spermatogonial stem cells. The thinking is that these stem cells can be retransplanted following cancer treatment to grow spermatogonial tissue, or be used to grow sperm in vitro to preserve fertility. Though researchers have yet to produce sperm using human spermatogonial tissue, work by Dr. Brinster’s lab has shown that the approach works in a mouse model.
Dr. Ginsberg has compared the development of TTCP to that of in vitro fertilization (IVF), which took 15 years to go from the lab to the birthing suite. “If everyone keeps saying ‘it’s too experimental,’ we’ll never get anywhere,” Dr. Ginsberg said in a recent Nature Medicine article about the program. “Everyone was saying IVF was too experimental years ago, and now it’s not. All of these things have to start somewhere.”
“Really Positive” Reaction
However, there have been concerns associated with testicular tissue cryopreservation. In addition to the skepticism that accompanies any new research, there have been ethical concerns about the tissue removal surgery. In particular, there are worries that the surgery is too invasive, given TTCP’s experimental nature.
To allay these concerns, the tissue removal surgery is coupled with another regularly scheduled procedure. “We don’t want to expose the children to another general anesthesia since there is a risk with any general anesthesia, so we wanted to make sure it was coupled with another trip to the operating room,” Dr. Ginsberg said.
Indeed, according to a questionnaire handed out after the treatment, coupling the testicular tissue removal procedure with another surgery has led some families to agree to take part in the program when they might not have been interested, Dr. Ginsberg pointed out.
Moreover, “even though this is experimental, and we basically tell the families that we’re not even sure the tissue will be usable for their children, 80 percent of the patients approached are agreeing to do the procedure,” Dr. Ginsberg said.
And thanks to a recent award from the St. Baldrick’s Foundation, the testicular tissue cryopreservation program is set to expand to two other institutions. For the first few years of TTCP work, Children’s Hospital was the only center that could accept patients, but the St. Baldrick’s grant will allow the Testicular Cryopreservation Consortium to expand beyond CHOP to include Seattle Children’s Hospital and Memorial Sloan-Kettering Cancer Center.
Overall, families’ reaction to the TTCP program has been “really positive,” Dr. Ginsberg said.
To learn more about CHOP’s cancer treatment, survivorship program, and research, see the Cancer Center.