Ovararian Transplants in Cancer Patients & Their Implications: Are we challenging nature too much?

By: Helen Beilinson

Cancer results from the accumulation of mutations within normal cells in our bodies that result in their abnormal and uncontrolled growth. These cells replicate very rapidly and amass to form tumors. Two of the most common treatments for cancer, chemotherapy and radiation therapy, function to eliminate cancer cells. Chemotherapy works by delivering chemical substances (such as anti-cancer drugs) into the patient, where they act as cytotoxic agents, killing cells that divide very rapidly. Chemotherapy is unfortunately not specific for cancer cells, just dividing cells, so it kills healthy cells as well. An infamous side effect of chemotherapy is  hair loss, or alopecia, which happens due to the cytotoxic effect of chemotherapy on hair follicles, a rapidly dividing cell type. Radiation therapy uses ionizing radiation, which takes advantage of high-energy rays, to kill cancer cells. Radiation can be targeted to a particular area within the body, as opposed to chemotherapy, which is predominantly administered into the blood stream. However, it still leads to the death of healthy, noncancerous cells, surrounding the tumor location.

Although cancer is predominantly known as a disease associated with age, youth doesn’t protect entirely from cancer. Teenagers and young adults can still be diagnosed with a variety of cancers. An unfortunate side effect in female cancer survivors is that chemotherapy and radiation therapy can often result in infertility, rendering the women unable to have children.

In an article this week in Human Reproduction, authors explored whether they could restore fertility in women who had survived cancer. To do this, before beginning cancer treatment, doctors removed either entire or partial ovaries from these patients who decided they would want to have children after treatment. They then cryopreserved the ovaries, freezing them at subzero temperatures for long-term preservation. After successful treatment of the women’s’ cancer, the surgeons transplanted the cryopreserved ovarian tissues back into their patients.

The doctors found that of the 32 women who chose to try to become pregnant after transplantation, 10 (31%) were able to conceive one or more children. Doctors estimate that women who do not undergo ovary transplants have a maximum of a 5% chance of conceiving after cancer treatments. A 25% increase is not too shabby.

Though it involves two additional surgeries, the treatment is very safe and has provided a lot of comfort to women diagnosed with cancers early in life. As Claus Yding Andersen, a reproductive physiologist who was involved in this study, said in an interview with Capital Public Radio, “Obviously, the thing that interests [patients] the most is to survive the cancers, but immediately after that they would say they are really interested in maintaining their fertility.” This advancement in transplantation medicine has provided cancer survivors with the ability to continue their life plans after the jolting reality of cancer.

This study, however, raises many moral questions. In 1970, the average age of a woman to have her first child was 21.4. Nearly half a century later, today the average age is 25.2. As women are having children later in their lives due to a variety of social, political, and economic reasons, many have considered freezing their eggs as a way for them to retain their fertility until a time when they are ready to have children. In light of the success of cryopreservation of ovaries of cancer patients, physicians have began asking whether it should be available for women who are not cancer patients, giving them the chance to preserve their ovaries until a time when they are ready to have children.

Due to how egg cells develop in women, which I will not go into detail here, eggs that are released from ovaries earlier in life tend to be more healthy and have less potential mutations, compared to those released later in life. It is also believed that the uterus is not as affected by age as other reproductive parts. Thus, in theory, if a woman freezes her eggs and undergoes in vitro fertilization later in life, the woman is very likely to have a healthy pregnancy and a healthier child than if she chose to have children without in vitro fertilization. In theory, this idea is also applicable to transplanted cryopreserved ovaries. However, many other problems deserve consideration. For example, due to decreased estrogen production later in life, the mother will be less able to produce milk to feed her child.

 

Of course, advances in medicine are always incredible—especially when we are able to protect and conserve such a complex system as pregnancy. However, there may be unknown consequences to having children later in life, especially by more medically aided means. Evolution has shaped the way our bodies work for millions of years. Evolution functions not only to advance traits that are helpful in a particular organism, but also to maintain a balance between all systems within that particular organism. Medicine has changed how our bodies interact with the outside world (with treatment of infectious diseases) and how our bodies handle changes within us, such as cancer or pregnancy. Medicine is able to target specific problems or concerns of patients, however, targeting one problem can off set known and unknown factors leading to unforeseen consequences. There is still a lot to be learned about how offsetting the age at which organisms have children can affect the offspring. Although medical advances have been incredibly helpful in some situations, such as allowing women who have lost their fertility do to cancer treatment to mother children, they also raise moral and ethical questions that should be considered before allowing such treatments to be used by everyone.