NEW YORK (Reuters Health) – Even after highly gonadotoxic cancer treatment, long-term ovarian function and fertility can be restored by repeated heterotopic ovarian tissue autotransplantation, researchers in Korea and the US report in the June issue of Fertility and Sterility.
In cryopreserved ovarian tissue, ischemia after orthotopic grafting causes a substantial loss of follicles, shortening the life span of the tissue, so repeated transplantation may be required, Dr. S. Samuel Kim at the University of Kansas, Kansas City, and his co-investigators note.
Heterotopic transplantation may offer a viable alternative, the authors note, but until now, no viable pregnancies after such a procedure have been reported.
Their current report is a prospective clinical case series of four patients following completion of cancer treatment. The team collected a whole ovary each patient, and after sectioning (up to 10 x 10 x 2 mm in size) and processing, stored the cortical tissue samples in liquid nitrogen.
For transplantation, 8 to 10 thawed sections were threaded onto suture material. Through a 1-2 cm skin incision in the abdomen, the tissue was placed into a space created between the rectus sheath and the rectus muscle.
After the first such transplantation, hormone levels and follicular development indicated that ovarian function returned between 12 and 20 weeks after transplantation, but lasted only 3 to 5 months.
However, a second attempt in three patients who remained in cancer remission was associated with faster return of function (between 2 and 4 months), lasting for 15 to 36 months. At times, patient symptoms along with progesterone elevation indicated spontaneous ovulation.