miércoles, 23 de marzo de 2011
Fertility Still Possible for Many Male Cancer Survivors | NCI Cancer Bulletin for March 22, 2011 - National Cancer Institute
March 22, 2011 • Volume 8 / Number 6| NCI |
Fertility Still Possible for Many Male Cancer Survivors, Study Finds
A retrospective study has shown that healthy sperm could be retrieved from male cancer survivors who had no viable sperm in their semen 2 decades after being treated for cancer.Many male survivors of childhood cancer have long been thought to be sterile and, therefore, incapable of conceiving a child. But a new study suggests that conception and fatherhood may be possible for a substantial number of these men, through the use of a surgical procedure to retrieve healthy sperm combined with a form of in vitro fertilization (IVF).
In the retrospective study, researchers from New York-Presbyterian Hospital/Weill Cornell Medical Center showed that nearly 2 decades after cancer treatment, healthy sperm could be retrieved from the testicles of more than one-third of male cancer survivors who had a condition in which no viable sperm was detectable in their semen. Following sperm retrieval, IVF procedures led to a 50 percent pregnancy rate and a slightly lower overall rate of child birth.
The findings were published online March 14 in the Journal of Clinical Oncology: Successful Treatment of Postchemotherapy Azoosperm... [J Clin Oncol. 2011] - PubMed result.
Use of the sperm-retrieval procedure, called microdissection testicular sperm extraction, or microTESE, in cancer survivors has been limited, explained study leader Dr. Peter Schlegel, chair of the Department of Urology at NY-Presbyterian/Weill Cornell, who developed microTESE and performed all of the procedures in the study. “Having this sort of information about our experience, and more details about who tends to do well, will be very important for expanding the potential utilization of [microTESE],” he said.
A very low sperm count is a common, long-term side effect in men who received chemotherapy in childhood or adolescence. In this study, the NY-Presbyterian/Weill Cornell researchers analyzed 73 male cancer survivors with this condition, known as azoospermia, who had undergone microTESE procedures between 1995 and 2009. On average, the procedures were performed nearly 19 years after cancer treatment.
Healthy sperm was retrieved from 37 percent of the men and in approximately 43 percent of individual procedures, since some men underwent microTESE more than once. Using a process called intracytoplasmic sperm injection (ICSI), single sperm were then used to fertilize an egg, with an overall fertilization rate of 57 percent. Thirty-six embryo implantation procedures were performed, half of which resulted in a pregnancy. Overall, 20 children were ultimately delivered, including 5 sets of twins.
The availability of healthy sperm appeared to be associated with the type of chemotherapy received, Dr. Schlegel noted. Men treated with platinum-based chemotherapy agents had the highest retrieval rates. For example, men treated for testicular cancer, for which the platinum-based chemotherapy drug cisplatin is a standard treatment, had an 85 percent retrieval rate. Men treated with alkylating agents, which are commonly used to treat lymphomas and sarcomas, had the lowest retrieval rates.
“MicroTESE and ICSI revolutionized the treatment of men with azoospermia from testis failure, such as those who have had chemotherapy,” said Dr. Craig Niederberger, head of the Department of Urology at the University of Illinois at Chicago Medical Center. Before the availability of microTESE “you would just do a testis biopsy, and if you found no sperm, it was game over,” he said.
With microTESE, the surgeon uses optical magnification to examine the testis more closely and identify seminiferous tubules, hollow tube-like structures that transport semen, that are dilated and thus likely to contain sperm. Studies Dr. Schlegel has conducted indicate that, compared with other standard methods, microTESE not only increases the success rate of sperm capture, but also the quantity of sperm obtained and with less damage to the testicle.
The study’s findings “should not be interpreted by medical oncologists as ‘We don’t need to offer sperm cryopreservation prior to beginning chemotherapy,’” Dr. Niederberger stressed. “Already there is a lot of pressure to not do it because they want to get cancer therapy started as soon as possible.” But cryopreservation is still the best way to give adolescents and young men with cancer the potential to have their own children in the future, he said.
At the time they were treated for their cancer, most of the patients in the current study were old enough for sperm collection, noted Dr. Robert Brannigan, an associate professor of urology at the Northwestern University Feinberg School of Medicine. Fertility preservation is often still absent from many discussions between patients and their oncologists, he continued, including pediatric oncologists who typically treat adolescent patients.
A recent nationwide survey of pediatric oncologists, for example, found that many pediatric oncologists don’t routinely refer adolescent patients to fertility specialists.
For many oncologists “there can be discomfort in speaking specifically about reproductive health issues, particularly with adolescent patients,” Dr. Brannigan continued. Timing, cost, and insurance coverage can also be barriers to fertility preservation, he added.
“Even in the best hands and with this excellent technique, only a minority of patients with azoospermia after chemotherapy have sperm found and extracted,” Dr. Brannigan said.
“These are very difficult cases, and Dr. Schlegel’s success rates are outstanding,” he continued. “But this study underscores that many of these patients may not have needed to undergo this procedure in the first place if they had had [fertility preservation] counseling before starting treatment for their cancer.”
—Carmen Phillips
Biography - Carmen Phillips
Carmen Phillips has been writing about science and medicine for nearly 15 years. During that time, he’s written about a wide array of topics, including infectious disease, cardiology, oncology, and health care policy. Prior to coming to NCI, Carmen wrote for the American Red Cross, WebMD, and the American College of Cardiology; he has a master’s degree in science-medical writing from Johns Hopkins University. Carmen’s writing interests include cancer prevention, late-stage clinical trials, and translating innovative research into the clinic. During work hours, you can find him on Twitter @CarmenBPhillips and @NCIBulletin
Biography - Carmen Phillips - National Cancer Institute
For more on this subject, read: Preserving Fertility While Battling Cancer: NCI Cancer Bulletin for January 11, 2011 - National Cancer Institute
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NCI Cancer Bulletin for March 22, 2011 - National Cancer Institute
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