Introduction:
Chemotherapy, radiation, and surgical resection are examples of gonadotoxic treatments used to treat disease, gender affirmation surgery, malignancy, or medical disorders that can permanently impair reproductive function. Ovulation and the menstrual cycle are the key aspects of the female reproductive system. Women have regular monthly menstrual periods during their reproductive years because they ovulate regularly each month. Eggs mature inside fluid-filled spheres called "follicles." At the beginning of each menstrual cycle, when a woman is having her period, a hormone produced in the pituitary gland (follicle-stimulating hormone (FSH)), located in the brain, stimulates a group of follicles to grow more rapidly on both ovaries. At the same time, male fertility is not determined by semen or sperm traits alone. Additional factors (i.e., hormonal, immunological, genetic/chromosomal, behavioral) are relevant besides semen quality.
What Are the Agents Affecting Fertility?
Gonadotoxic is related mostly to the agents used in treating cancer. Regimens, including chemotherapy and radiotherapy, can cause adverse effects on gonadal function relative to dose-related.
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Chemotherapy:
Chemotherapy protocols have the potential for gonadal toxicity as per American Society of Clinical Oncology (ASCO) recommendations on fertility preservation. Among chemotherapeutic drugs, the alkylating agents, particularly Procarbazine and Cyclophosphamide, appear to cause the most elevated hazard in a dose-related mode, with the highest doses inducing a significant probability of permanent amenorrhea. However, amenorrhea induced by chemotherapy treatment may be temporary, and menstruation may return after several months post-treatment. The gonadotoxic effect of chemotherapy is influenced by the patient's age, type of chemotherapy, dosage, and the number of cycles employed.
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Radiotherapy:
Gonadal injury caused by field radiation of the total body, mainly the abdominal or pelvic region, disrupts the hypothalamic-pituitary axis function, provoking ovarian failure or direct damage to the uterus. Oocytes are especially sensitive to radiation, with an estimated dose of less than 2 Gy needed to destroy 50 % of primordial follicles. The magnitude of the adverse effect is related to dose, fractionation schedule, and age at the time of treatment which increased the risk of miscarriage, premature delivery, low birth weight, maternal bleeding, and damage to structures and vessels in the pelvis and abdomen.
What Are the Procedures for Women to Preserve Fertility Before Cancer Treatment?
Women who are close to undergoing malignant tumor treatment have various options regarding fertility preservation.
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Embryo Cryopreservation: This process requires harvesting eggs, fertilizing them, and freezing them. Thus, they can be implanted later. Studies suggest that embryos can survive the freezing and thawing process up to 90 % of the time.
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Egg Freezing or Oocyte Cryopreservation: The method involves unfertilized eggs harvested and frozen, but human eggs do not survive freezing as well as human embryos.
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Radiation Shielding: The best method to prevent radiation-induced damage is using small lead shields positioned over the ovaries to diminish radiation exposure.
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Ovarian Transposition or Oophoropexy: The procedure involves surgically repositioning the ovaries in the pelvis to save them from radiation when delivered to the pelvic area. Thus because of scatter radiation, ovaries cannot be protected completely as the ovaries are radiosensitive, and scatter radiation can lead to damage. Still, the chance of ovaries being protected through this method is relatively high. With the help of a lead shield, the ovaries are protected. After completing the total radiation sessions, repositioning of the ovaries is done.
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Surgical Removal of the Cervix: To handle early-stage cervical cancer, a large triangular-shaped cervix, including the cancerous area, is withdrawn, called cervical conization. The rest of the remaining cervix and the uterus are conserved. Alternatively, a radical trachelectomy is called a partial or total removal of the cervix and the connective tissues following the uterus and cervix.
What Are the Procedures for Men to Preserve Fertility Before Cancer Treatment?
The following methods can be used for men desiring to preserve their fertility before undergoing cancer treatment.
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Sperm Cryopreservation: The best and safest procedure involves freezing and storing sperm at a sperm bank or fertility clinic for use later.
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Radiation Shielding: Using the small lead shields to position over the testicles to diminish the amount of radiation exposure to receive.
What Can Parents Do to Preserve the Fertility of a Cancer Child?
Fertility issues should be discussed with children treated for cancer as soon as they are old enough to understand. The parent's and the child's consent might be required before a procedure can be accomplished. If the child has begun puberty, options include oocyte or sperm cryopreservation. Females who have cancer treatment before puberty have an option for ovarian tissue cryopreservation. In this procedure, ovarian tissue is surgically extracted, frozen, and later thawed and reimplanted after tumor radiation. Whereas for preserving fertility in boys undergoing cancer treatment before puberty, testicular tissue is surgically removed and frozen.
Does Fertility Preservation Interfere With Successful Cancer Therapy or Increase the Recurrence Risk?
No evidence suggests that current fertility preservation methods can directly affect the success of cancer treatments. Regardless, one may compromise the treatment success if one delays surgery or chemotherapy to seek fertility preservation.
There seems to be no advanced chance of cancer recurrence associated with most fertility conservation methods. Regardless, there is a possibility that during the reimplantation of frozen tissue, tumor cells could be reintroduced depending on the type and stage of cancer. So, in that case, advice should be sought from the experts for better results.
Conclusion:
Prevention is better than treatment or cure. But it is always equally important to diagnose and treat the disease or disorder as soon as possible. Malignant tumor treatments mostly involve chemotherapy and radiation that can induce adverse effects. Radiation can cause deterministic (which causes damage related to superficial areas like mucositis, where inflammation of the oral mucous membrane) and stochastic effects (which cause DNA alteration, which can induce the mutation or secondary radiation-induced cancer, mainly leukemias) on the body. Gonads are the radiosensitive organs or systems of the body which require protection and preservation. However, any delay in cancer treatment due to gonadotoxicity can be fatal for an individual. Thus, it is better to contact the experts for a better method with a great outcome.
