A new study carried out in the United States in which data from 337,754 people have been analyzed has revealed that both men who have fertility problems, as well as their relatives, have a higher risk of developing various types of cancer and of the disease appearing at a younger age, compared to families of fertile men.
The results have been published in the prestigious reproductive medicine journal Human Reproduction and have found for the first time risk patterns for various types of cancer in men with fertility problems and in their families. The researchers, led by Dr. Joemy Ramsay, assistant professor at the University of Utah, Salt Lake City, USA, found that the risk and type of cancer varied significantly, depending on whether the men had a low amount of of sperm (oligozoospermia) or none (azoospermia), and identified several cancers in different family groups.
The authors of the work hope that their findings will help improve the understanding of the biological mechanisms involved in both cancer and infertility, since this would allow doctors to make more accurate predictions about the risk of cancer in men with fertility problems. fertility and their families, and improve the advice offered to them.
Association between subfertility and cancer and risk for families
Dr. Ramsay and her team analyzed results from semen analyzes performed between 1996 and 2017 on 786 men who attended fertility clinics in Utah, comparing them with information from 5,674 fertile men in the general population who had at least one child. Of the men with fertility problems, 426 were azoospermic and 360 had severe oligozoospermia (less than 1.5 million sperm per milliliter of semen).
Researchers collected information on first-, second-, and third-degree relatives using the Utah Population Database, and cancer diagnoses were identified from the Utah Cancer Registry. Looking at all families of azoospermic men, the researchers found a significantly increased risk of five cancers: bone and joint cancer (156% increased risk), soft tissue cancers such as sarcomas (56% increased risk), of uterus (27% increased risk), Hodgkin lymphomas (60% increased risk), and thyroid cancer (54% increased risk).
Families of men with severe oligozoospermia had a significantly increased risk of three cancers: colon cancer (16% increased risk), bone and joint cancer (143% increased risk), and testicular cancer (134% increased risk). . The researchers also found a 61% decrease in the risk of esophageal cancer.
They found that cancer risk and cancer types varied considerably among families of men with fertility problems, both by type of subfertility and within the same type, which could explain the inconsistent associations between subfertility and cancer in studies previous.
Families of men with severe oligozoospermia had a significantly increased risk of three cancers: colon cancer, bone and joint cancer, and testicular cancer.
For example, the study found an increased risk of testicular cancer in only one-third of family groups of oligozoospermic men, but the increased risk ranged from four to 24 times depending on the family group. Among the families of oligozoospermic men, there were 12 distinct groups and all had an increased risk of at least one type of cancer.
Among the families of azoospermic men, the researchers identified 13 family groups. One group, which included most families, had a cancer risk similar to that of the general population. However, the other 12 groups all had increased risks of developing at least one type of cancer.
Dr. Ramsay highlighted that the study identified several unique patterns of cancer risk in families of men with poor fertility and that when family members share patterns of cancer risk, it suggests that they have genetic, environmental or behavioral factors in common. of health.
Genetic and environmental exposures can also interact to increase cancer risk, but identifying groups of families with similar patterns of cancer risk can improve understanding of the biological mechanisms of both cancer and infertility, says the study. researcher, who adds that this will help evaluate the risk of cancer for families and allow patients to be better counseled.
Researchers have conducted genetic sequencing studies to look for specific genetic mutations that may be driving the associations between subfertility and cancer seen in this study. Strengths of the study include the use of population registry data for family structure, cancer diagnosis, and subfertility.
Saturnino Luján, urologist at the Hospital Politécnic i Universitari La Fe in Valencia and at the IVI clinic (Valencian Infertility Institute) explained in statements to SMC Spain: “There are studies that have already analyzed the relationship between infertility in men and possibility of suffering from different types of cancer, such as testicular cancer. The authors go further and analyze not only the risk to the patient, but the risk of cancer to the offspring of these patients. The implications of this study would be to inform family members about this potential risk and promote early prevention studies of oncological processes.”
However, the expert points out: “One of the main limitations of the study is that the presence of risk factors for developing tumors such as obesity, smoking or contact with environmental toxins is not analyzed. The hypotheses that support this risk of cancer in patients with infertility and their descendants could be due to heritable genetic mutations, environmental risk factors or a combination of both.
