With the advent of better treatments, more young patients treated for childhood cancers are surviving longer, and many reach the age when they consider starting families.
However, the life-saving treatments for pediatric cancer patients can result in side effects that permanently harm reproductive cells and tissues, jeopardizing their fertility. Now, specialists at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center are offering counseling about the many options that are available for preserving fertility and are making referrals for interventions if patients want to pursue them.
The program provides a fertility consultation with each new patient and their family before the start of treatment as part of the patient’s comprehensive work-up, according to Katelynn Brodigan, FNP, nurse practitioner for the Pediatric Fertility Preservation Program at Dana-Farber/Boston Children’s.
“The main objective, of course, is to start treatment aimed at survival,” notes Brodigan, “but we are also more focused on quality of life going forward than in the past, since we know much more about these drugs and their harmful effects on fertility.”
What Impacts Fertility?
The chemotherapy drugs that are most likely to impair fertility are alkylating agents and heavy metals, such as cyclophosphamide, busulfan, carboplatin, and cisplatin, which interfere with the cancer’s DNA. Radiation that impacts the pelvic region can also harm reproductive organs and tissues.
Patients who undergo stem cell transplants are also generally at high risk of becoming infertile, because they often receive total body irradiation and/or chemotherapy with alkylating agents.
Fortunately, there are multiple strategies for preserving fertility, and new options are being developed and tested.
Preservation for Males
Sperm banking is recommended for boys who have undergone puberty and will be receiving therapy that can cause permanent damage to sperm production.
“We generally recommend sperm banking for all males who are able to produce a sample even if their treatment poses low risk to future fertility,” says Brodigan. “It’s a nice ‘insurance policy’—it’s relatively easy and non-invasive, and once the patient is off treatment, we can re-evaluate and see whether it’s necessary to maintain the specimen in long-term storage.”
For boys who have reached puberty but can’t produce a sperm sample, a urologist may perform a surgical biopsy of the testicle to obtain tissue from which sperm can be extracted for banking.
Another option, testicular tissue cryopreservation, is aimed at preserving fertility even for boys who haven’t entered puberty, and who don’t produce sperm. Their testicles contain stem cells that are precursors for sperm, and these stem cells may be damaged by cancer therapies.
In this procedure, small pieces of testicular tissue are surgically removed prior to treatment and are frozen for future use. This method is considered experimental, and no human pregnancies resulting from frozen testicular tissue have yet been reported in the medical literature. The hope is that new therapies will be available in the future to achieve pregnancies from cryopreserved testicular tissue.
Preservation for Females
Female patients who are post-pubertal can opt to have their eggs harvested and frozen for potential later use to achieve a pregnancy. This is an established method that has been used to achieve hundreds of births. Another option is to have the eggs fertilized with sperm from a partner or donor to create an embryo, which can be frozen for future use.
Harvesting eggs requires that the female patient take hormones to stimulate the formation of multiple follicles in the ovary, which contain eggs that are removed in a minor surgical procedure and then frozen. This process takes about two weeks and will delay the start of cancer therapy. If the patient’s doctors feel it’s imperative to begin treatment immediately, this option may not be recommended.
Another new option, though still in its experimental phase, eliminates the delay in treatment for young female patients. Instead of giving hormones to stimulate follicle formation within the ovaries, doctors can remove an ovary and process it, freeze it, and store it for future use. When the patient wants to become pregnant, slices of the frozen ovarian tissue are thawed and re-implanted by grafting the tissue to the remaining ovary.
This option is considered experimental, but Brodigan says it has been used to achieve more than 140 live births, “so we know it works.” Ovarian tissue freezing is available for all ages, including young girls who have not yet gone through puberty, she says.
Learn more from the Pediatric Fertility Preservation Program at Dana-Farber/Boston Children’s.