Decreased Libido

A loss of desire for sexual activity is a common symptom raised by both men and women who have received treatment for cancer. There are many more studies describing this in women than in men. Studies describe changes in sexual functioning, including desire and satisfaction were a problem for over 40% of women treated for cancer.^{21 38} For men, there are a few published reports addressing decreased libido and sexual function changes as side effects of therapy for cancer.^{28 58}

There are many possible logical reasons why this might occur. Reasons might include stress related to the diagnosis and treatment, fatigue related to treatment, and changes in self image. Another reason might be a change in hormones. For women, the lack of estrogen may be part of the problem. For men, the lack of testosterone could be the problem. Research points to the role of testosterone in sexual desire or libido.²⁴ Many studies of men who have had testosterone supplementation have reported improved libido. Likewise, women who have had surgical removal of their ovaries, causing a decrease in testosterone levels, have reported improved libido from taking testosterone treatment.

Men with a history of prostate cancer cannot take testosterone, as this could make their cancer grow. Therefore, alternative therapies are needed for men. Research is lacking in this area. Counseling has been shown to have some positive effects and will be discussed further.

For women who have had chemotherapy treatment for cancer, it is not known how their testosterone levels are changed. We know that estrogen and progesterone decrease, but we do not know if testosterone decreases. The woman's ovaries make half of the testosterone in her body once she goes through menopause.⁵² Many women are not aware of this information.

It is not known if taking testosterone is safe for women who have had cancer. The body can change testosterone into estrogen and therefore, it would not be safe for women with breast or ovarian cancer to take testosterone. There is also no testosterone on the market in a dose that is approved for women. Studies are going on right now to try to find out how much testosterone changes in women after chemotherapy for breast cancer, whether low testosterone is linked to unwanted symptoms in women, and whether there is a type and dose of testosterone that is not changed into estrogen and might be safe for women to take. Much research is needed in this area.

Various types of counseling have been studied with respect to improving sexual desire and satisfaction. Counseling can be helpful in coping with the stresses of being diagnosed and treated for cancer, as well as coping with changes in body image and emotions.¹² There are also specific things that a counselor trained in sexual therapy can teach to improve intimacy.¹² Your health care provider can refer you to a specialist who can help in this area.

Cognitive dysfunction and Alzheimer Disease

Another area of great controversy with very little evidence is whether cognitive function(how your brain works) and more specifically, the risk of getting Alzheimer disease is associated with estrogen and testosterone deficiency. There are studies about chemotherapy and cognitive function which are well explained in this website under cognitive function. The role of estrogen or testosterone in cognitive function is not well understood.

Although women are at greater risk for developing Alzheimer disease, it is not clear if that risk is due to a decrease in estrogen. One of the problems with evidence that states estrogen and decreased cognitive function are linked is that there is that these studies do not always take into account the great age range of the people observed in the study. There is also a change in many hormones as you age and go through menopause. To highlight the unknowns, one study done with 393 community women ages 55 to 89 years found that cognitive tests were more strongly linked to testosterone levels, not estrogen levels⁴. Furthermore, studies that have used estrogen to improve or prevent Alzheimer Disease have not been conclusive, including the Women's Health Initiative Study that just published several papers stating dementia was worse in those taking estrogen/progesterone supplementation.^{19 35 53 54} More research is needed to make sense out of any connection between hormones and cognition.

In addition, there is some evidence that men have problems with memory and spatial ability as they age, particularly if they have low testosterone levels.²⁴ Studies have shown that in men, cognitive abilities improve when men are given testosterone.²⁹ Again, studies are needed to better explain the link between testosterone and brain function and alternative therapies to help keep brain functioning high are needed.

One thing that does seem to be clear from the research on Alzheimer Disease in both men and women, is that using the brain is the best way to maintain function. Doing mathematical tasks (such as balancing your checkbook without a calculator - then use the calculator to double check the math) and performing mind puzzles and crossword puzzles are good exercises.⁵⁷ In addition, avoiding smoking and alcohol, which harm brain cells is another good practice. Things that increase blood flow to the brain (like exercise) and decrease harm to the cells (such as antioxidants) are not proven to decrease risk and increase function, although it makes sense that they might be helpful. Such studies are still needed.

Weight Gain and Muscle

Weight gain, particularly gaining weight in the belly area, is a common occurrence with age and is one of the things that increases a person's risk for heart disease. Many articles suggest that weight gain in older age may be connected to less activity but also changes in hormones. Testosterone is one hormone that is linked in studies to fat and muscle.^{6 56} Less testosterone is associated with more body fat, less lean muscle mass and less muscle size.⁵⁶ This has been shown mostly in men, but there is evidence this might be also true for women.

Much more research is needed in this area. However, there are things men and women can do to prevent weight gain and muscle loss as they age. Exercise as discussed earlier is extremely important. In addition, simple weight training will not only help maintain muscle mass, but will also help with weight control as more muscle burns more fat.