New fertility preservation methods

January 27, 2010 4:27:23 PM PST
New fertility preservation methods for men and women are at risk of becoming infertile.

FERTILITY PRESERVATION
Fertility preservation is a new field of medicine aimed at helping men, women, adolescents and children to overcome one of the most common, serious and impactful complications of cancer treatment: infertility. In addition, it seeks to help preserve fertility in patients without cancer but who may be at risk of losing their fertility in the future from conditions such as ovarian cysts, early menopause, lupus, and other syndromes. The need and excitement for this field has arisen because:

  • Medical care is now shifting from the problem of cancer cure toward improved quality of life among survivors.

  • Fertility is a key quality of life issue for many cancer patients.

  • Many exciting new methods of overcoming infertility have been developed for cancer survivors and several experimental approaches to fertility preservation are currently being developed.
Fertility Preservation for Men
  • Gonadal Shielding: As its name implies, this involves using shielding devices to protect radiation treatments from directly striking reproductive organs.

  • Sperm Banking: This involves freezing healthy sperm before cancer treatment for use at a later time for conceiving. Some level of assisted reproduction (IUI, IVF) is needed to use this sperm.

  • Testis-Sparing Cancer Surgery: It is now common to remove only the cancerous nodule instead of the whole testis in selected patients with testis cancer.

  • Sperm Mapping: Often men who survive cancer treatment have no sperm in the ejaculate. However, they may have small numbers of sperm in the testis, too few to get into the ejaculate. Sperm "mapping" is a technical advance that has allowed men who have no sperm in the ejaculate to have children. Dr. Turek pioneered this technique in 1997. It involves non-surgical needle sampling of the testis to determine if and where sperm are located in the testis. Such sperm can then be retrieved for use with assisted reproduction (IVF-ICSI).

  • Electrojaculation: This involves use of a special medical instrument to help people with spinal cord injury and other types of nerve damage to produce semen for fertility purposes.

  • Nerve-sparing Surgical Techniques for Cancer: Surgical advances have helped men remain potent and fertile after treatment for testis cancer and other malignancies.

  • Testis Tissue Preservation: Freezing testicular tissue from adult men is valuable as sperm may be found in the testis tissue despite the lack of sperm in the ejaculate. Since cancers can make men unhealthy, affected men often lack ejaculated sperm and only have testis sperm available for future paternity.

  • Testis Stem Cell Banking: In pre-pubertal boys with cancer, ejaculated sperm is not present. Despite this, it may be possible to freeze the stem cells from the testicles of boys before they receive sterilizing cancer treatment. It is likely that the frozen testis stem cells can be used later on after thawing to create sperm through maturation in a Petri dish or even being transplanted back into the same individual after puberty and after the cancer is treated.
Fertility Preservation Approaches for Women
  • 'Emergency' IVF: The creation of embryos after fertilizing eggs with sperm in a dish is an excellent and established way of preserving female fertility. However, it is only useful for post-pubertal women who have a partner or donor sperm source, and who can "afford" to postpone cancer treatment for several weeks to be able to proceed through the IVF process.

  • Egg Freezing: Egg or oocyte freezing is the process of obtaining unfertilized eggs from a post-pubertal woman and freezing them. In this situation, no sperm are needed. Although it is still in the experimental stages and the survival rate of unfertilized eggs on thaw is low, this may be a good strategy to preserve the fertility of some women.

  • Ovarian Tissue Harvesting & Cryopreservation: Ovarian failure and infertility is a common consequence of cancer treatment in many patients. Harvesting and banking ovarian tissue can be used to re-establish reproductive potential in women with cancer. Once a cancer cure is established, the thawed ovarian tissue is re-implanted into the woman with the hope that it will function. One safety issue is whether there might be residual disease in the transplanted ovary that might cause cancer recurrence. Alternatively, eggs may also be grown to maturity from the harvested ovarian tissue in a laboratory and fertilized with sperm and the resulting embryos transferred back for fertility treatment after cancer treatment.

  • Ovarian Transposition: Preservation of ovarian function is an important concern in reproductive-age cancer patients whose treatments include radiation therapy to pelvic structures near the ovaries. Ovarian transposition is an established technique that was developed to move the ovaries from their normal position to another location where the radiation will not directly injure them. It can now be performed laparoscopically on a same-day surgery basis.

  • Ovarian Suppression: It may be possible to "shut down" or "put to sleep" the ovaries with drugs in advance of sterilizing cancer treatment to protect the delicate eggs from the effects of chemotherapy and preserve future fertility. However, conclusive science to support this approach is still lacking.
HELPFUL LINKS:

  • WebMD: "Saving Fertility When Cancer Strikes"

  • Fertile Hope

  • The OncoFertility Consortium

  • The Turek Clinic


  • Load Comments