Restoring Fertility
New research offers some reassurance that removing ovarian tissue from women before treatment for certain types of cancer and grafting it back afterward to restore fertility would not reintroduce the disease.
Chemotherapy and radiotherapy save lives, but damage the ovaries. Women have stored their ovarian tissue at centers around the world in anticipation that doctors will one day be able to re-implant it after cancer treatment.
Besides technical difficulties, the technique raises concerns that undetected tumor cells might lurk in the frozen tissue and trigger a recurrence of cancer.
In the first safety study of its kind, published this week in the European journal Human Reproduction, none of 30 mice developed disease after they received grafts of ovarian tissue from 18 women very sick with lymphoma, or cancer of the lymph nodes.
"We can now be more optimistic about the application of cryopreservation (freezing) and transplantation in cancer patients, although these reassuring findings should not be interpreted as an absolute indication of safety," said the study's lead investigator, Dr. Samuel Kim, a professor of reproductive endocrinology at the University of Washington in Seattle.
Other experts said they were encouraged by the findings but that ovarian transplants would not be safe for all types of cancer, and perhaps not for all lymphomas.
The study involved 18 women with lymphoma, but 13 of them had Hodgkins disease, a type of lymphoma that hardly ever spreads to the ovaries. There are 19 other types of lymphoma, each of which has a different propensity to grow and spread.
While Hodgkins lymphoma grows slowly, Burkitt's lymphoma is the most rapidly growing malignancy.
"The study involved only five cases of non-Hodgkin's lymphomas," noted Dr. Fernando Cabanillas, chairman of the lymphoma department at the M.D. Anderson Cancer Center in Houston, who was not involved with the research.
Autopsies showed no trace of disease in any of the mice given the ovary grafts.
For comparison, three other mice were given slices from a cancerous lymph node from a woman who had recurrent lymphoma. All of those mice developed human lymph node cancer.
"It's a bit reassuring, but it's not enough evidence, we need more," Cabanillas said.
Dr. Kutluk Oktay, a Cornell University researcher who has conducted key studies in ovarian tissue grafting, said that compared with other cancers, most lymphomas carry a low risk of re-igniting the disease through ovarian transplants.
Several other cancers would clearly pose a risk, Oktay said, including bone cancer in the pelvis, uterine cancer and any malignancy affecting the blood, such as leukemia.
If breast cancer has not spread, it is unlikely to pose a danger in ovarian grafts, said Oktay, who was not connected with the latest study.
Experts said that implanting the human tissue into mice is a good indicator of what would happen in women.
"This is the best we're going tget. It's very close to the human situation and (ethically) we wouldn't be able to do such a study in humans," Oktay said.
By Emma Ross
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