Oncofertility / Fertility Preservation

Men

Over the last couple of decades survival rates for cancer patients have improved dramatically. The population of young cancer survivors has increased today and hence the focus of cancer treatment has shifted from survival alone to quality of life after treatment. One major issue in young cancer survivors is loss of fertility potential after treatment.

Chemotherapy, radiotherapy and sometimes surgical dissection done for treatment of cancer affect spermatogenesis or sperm production. It is difficult to predict the ability of a person post cancer treatment to father a biological child and In such instances it becomes essential to preserve the fertility potential of the individual. In males it is done by collecting semen samples by masturbation and freezing them at -196 degrees Celsius. At this temperature the semen can be stored for an indefinite period until it is required to be utilized. When there are no spermatozoa in the ejaculate in certain conditions, sperms can be recovered by surgical means. Recovery of sperm production post treatment is variable due to

• Effect of treatment
• Pretreatment fertility potential
• Influence of cancer itself on the person's overall health

In cancer patients who are about to undergo treatment it would be a sensible option to freeze semen prior to treatment. Once the treatment is over when the person wishes to have children the frozen semen can be thawed and used.

Semen obtained by masturbation is analyzed for quality and is frozen in vials. One day later a small aliquot of the sample is thawed and checked for post thaw quality. Not every sample frozen will thaw the same. There is considerable difference in the thawing capacity of each individual semen sample and depending on this the number of samples to be frozen will be decided. A total of 5-6 samples with an abstinence period of 2-3 days in between is frozen. Whenever the couple decides to have a child, the sample is thawed and utilized for conception either through IUI or ICSI.

Semen freezing can also be a viable option for men prior to vasectomy and for men who are about to undergo treatment for conditions like psychiatric illness, diabetes etc since many of the drugs used for these conditions might affect the quality of sperms which will reflect on the fertility potential.

Women

As a consequence of the increase in the number of patients surviving cancer, greater attention has been focused on the delayed effects of cancer treatments on the quality of future life of the survivor. Increase in the awareness of the effects of cancer treatments on fertility has created a need for fertility preservation among men and women. This demand has led to advancement of various techniques to preserve fertility through assisted reproduction and cryopreservation. The available options range from clinically well-established techniques such as embryo cryopreservation to highly experimental ones such as ovarian tissue cryopreservation.

A woman's reproductive life span is finite and depends on the number of oocytes with which she is born. Ovaries, which are endowed with an irreplaceable number of follicles, are extremely sensitive to cytotoxic drugs that induce an irreversible damage. There is a possibility that the ovaries & oocytes get damaged due to chemotherapy causing premature ovarian failure thereby leading to premature menopause and permanent infertility. Older women are said to have higher risk of developing complete ovarian failure compared to young women with high follicular number.

Patients who are under the risk of developing future ovarian failure and those suffering from benign ovarian diseases and undergoing radical surgery may all benefit from fertility preservation technologies. Fertility preservation is especially challenging in children, as embryo or oocyte cryopreservation is neither ethical nor practical. Currently the only option that could be offered to child patients is ovarian tissue cryopreservation, provided that the families are thoroughly informed about the post thaw status of the technique.

Method of cryopreservation:

In case of oocyte and embryo cryopreservation, ovaries are stimulated with hormonal injections to induce the growth of multiple follicles. When the follicles reach a definite growth stage, final maturation induction is done. The eggs are subsequently removed from the body by transvaginal oocyte retrieval. The procedure is usually conducted under sedation. The retrieved oocytes are either frozen immediately (Oocyte Cryopreservation) or after insemination of sperm and development of embryo (Embryo Cryopreservation) using cryo-protectants at extremely cold temperatures.

Ovarian tissue cryopreservation involves freezing a part of the ovary and storing it in liquid nitrogen whilst therapy is undertaken.

Available techniques for Fertility preservation in women:

• Embryo Cryopreservation: IVF/ICSI can be performed to store embryos for future use, if the patient has a partner and enough time prior to treatment.
• Mature Oocyte Cryopreservation: Embryo cryopreservation may not be an option for single women unless they choose to use sperm donation. In these patients, if they have time to complete ovarian stimulation prior to cancer therapy, freezing mature oocytes can be considered instead.
• Ovarian Tissue Cryopreservation: Ovarian tissue contains follicles with oocytes arrested at first meiotic division. High surface and absence of zona pellucida make the follicles less susceptible to cryo-damage. This tissue can be later be thawed and implanted near the fallopian tube, where it starts to produce eggs, allowing normal conception to take place.

IVF with donor oocytes and donor embryo transfer are other alternatives in patients who suffer from premature menopause or low ovarian reserve due to cancer treatment. The number of options to preserve fertility is growing. These options vary depending on the patient's age, the time available, type of cancer and whether the likelihood of ovarian involvement is high.