Stored Ovarian Tissue Needs Testing Before Re-Implantation
Inadequate safeguards could mean a return of cancer, study warns
THURSDAY, April 24, 2008 (HealthDay News) -- Cancer can return in patients who have been successfully treated if ovarian or testicular tissue they had stored in hope of regaining fertility is transplanted back into their bodies without it being adequately checked for cancer cells, according to a new report.
Researchers at two university hospitals in Israel, writing in the April 22 issue of Human Reproduction, then warned that most fertility centers lack the skills and technology to ensure the tissue is free of residual cancer cells.Hundreds of cancer patients worldwide have ovarian tissue and testicular tissue frozen in the hope of being able to have children once their treatment has finished. However, it is possible for the original cancer to re-infect the body when the tissue is re-implanted.
"We think it's vitally important to raise awareness amongst cancer patients, fertility specialists, oncologists and hematologists. There are few fertility centers in the world with the expertise and the technology to run the types of tests on tissue that are needed to detect residual cancer," first author Dror Meirow, who leads the fertility preservation program at Chaim Sheba Medical Center, said in a prepared statement.
Over 10 years, Meirow and his team collected and froze several strips of tissue from 56 women about to receive chemotherapy for hematological cancers such as Hodgkin lymphoma, non-Hodgkin lymphoma and leukemia. Over the years, the strips were thawed and checked for cancer cells using the most modern methods available at the time. The results were compared with the same tests carried out on the patients' diseased tissue at the time of harvest to ensure the tests were capable of detecting cancer when it was known to be present.
Only one test ever detected minimal residual disease in ovarian tissue: modern, highly sensitive, real-time polymerase chain reaction (PCR), a test that amplifies sections of DNA to detect molecular markers that would indicate the presence of cancer cells. The authors suggested that, as methods for detecting cancer cells are improving all the time, and ovarian tissue can be stored for more than 10 years, tests to detect residual disease should be carried out just before transplantation rather than at the time of collection. To do this, it is necessary to freeze smaller pieces of ovarian tissue separately for minimal residual disease investigation.
"The next step is to inform patients about the increasing success of ovarian tissue transplantation, to continue to improve the success of ovarian tissue transplantation, but also to call on fertility centers that store ovarian tissue to look for minimal residual disease and to start freezing tissue now for future investigation," Meirow said. "All of this holds true for testicular tissue, too, although we are not so advanced in successfully removing, storing and transplanting testicular tissue as we are with ovarian tissue."
The American Cancer Society has more about ovarian cancer treatment.