Testosterone is essential for males, and low levels are usually related to several problems such as low energy levels, depression, anxiety, sexual dysfunction, and many others. The same happens in women, who start suffering from bone mineralization and cardiovascular problems when their sex hormones start plummeting. We can also find a clear association between female sex hormones and estrogen-dependent cancers like ovarian cancer and breast cancer. Does the same happen with testosterone?
There are many types of testicular cancer, and they are the most common tumor in Americans aged 15 to 35 years old. As such, they usually appear at a younger age compared to prostate cancer and other tumors which increase their prevalence as we age. However, we don’t really know much about the risk factors of testicular cancer. We do know that it has a genetic pattern and having a family history of testicular cancer is one of the risk factors. Another risk factor for testicular cancer is a condition called cryptorchidism, which occurs when one or both testes do not descend properly into the scrotum. But what about testosterone levels?
Testicular Cancer and Testosterone: An elusive association?
In certain types of testicular cancer, testosterone levels are higher than average. However, we should not be misled by this fact because these are rare types of cancer called Leydig cell tumors. These tumors are located in the cells that synthesize testosterone, called Leydig cells. Thus, elevated levels of testosterone are not causing Testicular cancer, but they are instead the consequence of tumor growth and excessive secretion by the tumor itself.
Going deeper into the association between testicular cancer and testosterone, we can find evidence for and against androgens and their receptors. There is very scarce evidence to link the concentration of androgens and the growth of testicular tumors, but we do know that the sensitivity to testosterone dictates which type of testicular tumor would be more prevalent. We can say, for example, that higher sensitivity to testosterone usually leads to seminomas while having lower sensitivity to testosterone leads to non-seminoma tumors.
We also know that men who display excess estrogens have a higher risk of being infertile and developing testicular tumors in their Leydig cells. These higher levels of estrogens are common in overweight and obese men who have an increased aromatase activity. The enzyme aromatase is known to convert testosterone into estrogens, reducing the circulating levels of testosterone when it is overexpressed, as in the case of excess adipose tissue.
The available studies and evidence about testosterone concentrations are not sufficient to make a clear statement about the influence on the risk of testicular cancer. However, there are certain facts we can take into consideration to interpret the evidence.
Interpreting the available evidence
We still don’t have a self-explanatory picture about the risk factors for testicular cancer, but as the years go by, more evidence is made available in the scientific field, providing us with enough data to draw our own conclusions. In this yet obscure field of medical knowledge, we can act as a detective does, fitting pieces with one another to reach a clear picture even if we don’t have a straightforward answer.
The first astounding and very unexpected piece of evidence was the Insulin-like growth factor 1 (IGF-1). Growth factors are hormone-like proteins that exert regulatory actions in the cell and usually leads to cell proliferation, cellular growth, and several other functions. It would be expected that people with a higher level of IGF-1 would have an increased risk of cellular proliferation resulting in testicular cancer. However, in science and medicine, not everything is exactly as we would expect.
A study published in the American Journal of Epidemiology examined over 500 cases and near 790 control patients starting with the assumption that taller men have an increased risk of testicular germ-cell tumors, and therefore they would likely have higher concentrations of growth factors, including IGF-1. However, the results of their investigation were not what they expected.
Instead of increasing the risk of testicular cancer, IGF-1 concentrations reduced the risk of seminomas, a common type of testicular cancer that originates from the epithelium in the seminiferous tubules. It was an impressive finding because IGF-1 had been related to breast and colon cancer. However, what’s the connection with testosterone?
This is where the second piece of evidence fits in. For many years, testosterone has been known to increase IGF-1 levels. We currently need more evidence to state IGF-1 has a protective role against the development of seminomas, but if that’s the case, a healthy level of testosterone would be beneficial to protect ourselves from testicular cancer.
Testosterone levels in testicular cancer survivors
Most evidence about testicular cancer and testosterone level is focused on testosterone replacement therapy on testicular cancer survivors. These individuals usually display a low testosterone level, which is commonly caused by the chemotherapeutic agents used to destroy the tumor itself.
It is essential to maintain a healthy level of testosterone in these individuals because there’s a link between low testosterone in testicular cancer survivors and the prevalence of chronic health problems. In these studies, older patients and those with excess adipose tissue were the ones with a higher chance of low testosterone levels. These patients usually develop high cholesterol problems, high blood pressure, diabetes, erectile dysfunction, depression, and anxiety compared to patients with higher testosterone levels.
Thus, we can say that even if the available evidence is not enough to make a definite statement about testosterone levels and testicular cancer, testosterone levels are important to take into consideration before, during, and after diagnosing and treating testicular cancer. Testosterone sensitivity has a predictive value, and higher levels might exert a protective effect through IGF-1.
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