Pediatric Cancer Researchers Look To Preserve Reproductive Potential of Survivors
While survival rates of pediatric patients with cancer are greatly improved, researchers and clinicians are evaluating how to best preserve the reproductive potential of survivors.
Thanks to advances in treatment, more than 80 percent of children, adolescents, and young adults diagnosed with cancer survive 5 years and beyond. Yet that success comes at a price: the adverse events of the disease, and of the treatment, can have lasting effects on the survivors' ability to reproduce and — if they are able to conceive — on their children.
As the number of young survivors grows, so does concern about the long-range impact of treatment. It has given rise to the interdisciplinary field of “oncofertility,” aimed at preserving the reproductive capacity of patients with cancer.
But, more than a decade after Teresa K. Woodruff, PhD, coined the term, the practice remains nascent. And, while the list of options for preserving fertility grows, patients and practitioners face a wide array of challenges, which are increasingly daunting for younger patients.
“Alkylating chemotherapy, irradiation of the CNS [central nervous system] and/or ovaries, and pelvic or genitourinary surgery, used to treat common childhood cancers, can adversely affect reproductive organs, altering pubertal development, hormonal regulation, fertility, and sexual function…significantly reducing quality of life.” the authors of a 2013 review wrote.1
It's not just an issue for females, said Daniel Green, MD, of St Jude Children's Research Hospital in Memphis, Tennessee. Dr Green, who co-authored the 2013 review published in the Journal of Clinical Oncology, said that alkylating agents, radiation therapy, and surgery affecting the testes or sperm delivery can have similar negative effects on fertility and on hormone production.
“What people are beginning to do is to investigate either reduction of drug dose or reduction of radiation dose, or elimination of radiation or elimination of particular drugs from the treatment regimen, to see whether the survival rate can be maintained” while lessening the impact on fertility.
The introduction of targeted and immune therapies brings new uncertainty to the impact of treatment on fertility.
The American Cancer Society advises that bevacizumab “can cause ovarian failure, and some women's ovaries never recover.” It also notes that tyrosine kinase inhibitors “cause birth defects in lab animals.”2
The effects on children, Dr Green said, are even less certain.
“We really don't know. Especially in pediatrics. The only antibody that is fairly widely used is an anti-GD2 antibody used for treatment of patients with advanced neuroblastoma. And we really don't know the long-term effect of that particular antibody on reproductive function,” he said.