MedicalResearch.com Interview with:
Eric J. Chow, MD, MPH
Attending physician, Seattle Childrens Hospital
Assistant professor of Pediatrics, University of Washington School of Medicine
Member of the Clinical Research and Public Health Sciences Divisions
Fred Hutchinson Cancer Research Center
MedicalResearch.com: What is the background for this study?
Dr. Chow: Adverse effects on reproductive health including fertility is a known side effect of cancer therapy, particularly among survivors of childhood cancer. However, much of this risk has been linked to radiation exposure and less is known about the effects of chemotherapy treatment alone, particularly newer drugs now being used more widely. We used data from over 10,000 survivors of childhood cancer (plus nearly 4000 siblings) who are part of the Childhood Cancer Survivor Study (CCSS) which tracks people who were diagnosed with the most common types of childhood cancer before the age of 21 and treated at 27 institutions across the US and Canada between 1970 and 1999, and who had survived at least 5 years after diagnosis. The CCSS is a resource study open to all investigators and funded by the US National Cancer Institute (ccss.stjude.org). We specifically examined the effect of various doses of 14 commonly used chemotherapy drugs on pregnancy and livebirth and excluded survivors who received any radiotherapy to the pelvis or the brain.
MedicalResearch.com: What are the main findings?
Dr. Chow: We found that among male cancer survivors, the chance of pregnancy by age 45 was only around 50%, compared to 80% for siblings. However, among female cancer survivors, the chance of pregnancy by age 45 was approximately 70%, compared to over 80% for siblings. In male survivors, the likelihood of fathering a child generally decreased as cumulative exposure to alkylating drugs increased. High cumulative doses of several alkylating drugs (cyclophosphamide, ifosfamide, procarbazine) and cisplatin were linked with a significantly reduced likelihood of fathering a child.
In female survivors, only busulfan and high doses of lomustine were directly linked with lower likelihood of pregnancy. Overall, female survivors were still less likely to conceive compared to siblings but the effect was much smaller compared to men. However, in women, the difference was more pronounced for those who delayed pregnancy until they were aged 30 or older.
MedicalResearch.com: What should clinicians and patients take away from your report?
Dr. Chow: This is one of the largest studies of pregnancy and livebirth in cancer survivors of any age who were not exposed to radiation to the pelvis or brain (both of which can affect fertility). Importantly, our study features a broad range of commonly used chemotherapy drugs, given at varying doses, which allowed us to establish more precise dose thresholds associated with reduced likelihood of having (female) or fathering (male) a pregnancy for survivors of childhood cancer. Our findings showed an association between risk and exposure to cisplatin among male survivors, a finding not consistently reported in survivors of childhood cancer previously. Female survivors can be reassured by the result that chemotherapy-specific effects in women who did not receive any radiotherapy to the pelvis or brain were generally few in relation to these reproductive outcomes, except with exposure to the highest cumulative doses.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. Chow: The association of risk with cisplatin exposure among male survivors should be investigated further, given the increase in use of that drug in many contemporary pediatric treatment protocols.
MedicalResearch.com: Is there anything else you would like to add?
Dr. Chow: Counseling of patients and families about fertility preservation before initiation of cancer therapy is important. In particular, sperm banking should be encouraged for all newly diagnosed pubertal men, since this is a proven method of fertility preservation.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Pregnancy after chemotherapy in male and female survivors of childhood cancer treated between 1970 and 1999: a report from the Childhood Cancer Survivor Study cohort
Chow, Eric J et al.
The Lancet Oncology , Volume 0 , Issue 0 ,
Published 22 March 2016
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Dr. Eric Chow (2016). Infertility Risk after Chemotherapy For Pediatric Cancers Varies Between Men and Women MedicalResearch.com