Woet L. Gianotten1 and Yacov Reisman1
(1)
Rehabilitation Centre De Trappenberg, Huizen, The Netherlands
Woet L. Gianotten (Corresponding author)
Email: woetgia@ziggo.nl
Yacov Reisman
Email: uro.amsterdam@gmail.com
4.1 Introduction
This chapter will focus on the various biological elements of sexuality and sexual function.
We will start with some relevant male–female (M-F) differences, which is in some way a “touchy topic,” since it is difficult to clearly distinguish the nurture aspects (education and social impact) from the nature aspects (biology). Touchy also because cultures tend to approach this differently with, on the one hand, some traditional cultures where women are not seen as equal and, on the other hand, egalitarian cultures where every M-F difference is categorically denied.
After that we will look at the sexual response and part of the “physical conditions” (such as anatomy, hormones, neurotransmitters, etc.) that are needed to let the sexual response take place. We will focus on those conditions that are relevant in the context of cancer and its treatment.
Finally, we will change from sexual function to “sexual dysfunction” and we will address some of the typical processes behind various sexual disturbances. Whereas in this chapter sexual dysfunctions will be approached in a general way, the next chapter will deal with the more typical cancer-treatment-related disturbances with ample attention not only for sexual function but also for sexual identity and sexual relationship as relevant pillars of sexuality.
4.2 Male–Female Differences
Part of the behavior as a girl or a boy and later as a woman or a man is shaped by the influence of parents, peers, media, and culture. Underlying these nurture elements, there is also a strong influence of nature, which starts very early in the uterus. Without the addition of androgen hormones the fetus will develop into female (female is the default). In case of an XY chromosomal pattern, the fetal testicle develops and starts producing testosterone, responsible for the development of the male genitals and for the typical male wiring in the brain. From shortly after birth till the beginning of puberty, there are no gonadal hormones acting. In spite of that, there are many differences in behavior when we compare boys and girls as groups. Boys and men are relatively more function-oriented, whereas girls and women are relatively more people-oriented. This is not better or worse, it simply is the way it is.
Then, when puberty commences, the gonadal hormones become active in two different ways. On the one hand, gonadal hormones have the “organizational” task of guiding the ripening of the body from girl to woman and from boy to man. This task is completed at the end of adolescence. The other is the “activational” task of orchestrating reproduction, sexuality, and also other aspects of behavior. The same gonadal hormones are responsible for a substantial part of (the differences between) male and female behavior. This hormonal “activation” will continue till at an advanced age.
Estrogen and progesterone are key elements for the woman, regulating the monthly cycle, with also influence on the mood. These two hormones more or less disappear after the last menstruation. Women have also androgen hormones (falsely called “male hormones”) with testosterone (T) as the main androgen. In her fertile life, half of the androgens originate in the ovaries, the other half in the adrenal glands. After menopause, the ovaries also gradually stop producing androgens, but the adrenal glands continue to produce T.
In men, androgens are the key gonadal hormones, with 95 % originating from the testicles and 5 % from the adrenal glands. Men do not have a sharp drop in hormones. Till the age of 40, the T-levels are more or less stable and after that there is an annual diminishing of 1–1.5 %.
Both in the man and in the woman, the androgen hormones have a major role in sexual behavior with T as the number one for sexual thoughts, for sexual desire, and for arousability, but also for some less-sexual aspects of behavior like mood and assertiveness.
So long as men or women are in good enough health, their T-levels suffice for sexual desire till at an advanced age. In men, the T-level is 10–15 times higher than in females and that probably is an important part of the explanation for the differences in sexual behavior. In bed, men tend to be more focused on penetration, on genitals, on orgasm (and on sexual performance), whereas women tend to be more focused on relationship, intimacy, and on sensuality. The high male T-level is probably also responsible for his higher assertiveness and lower emotional sensitivity. Another important difference is the rather even-tempered mood in most males versus the rather fluctuating mood in most women, because of hormonal changes throughout their monthly cycle and pregnancies.
To recap: (1) This is not giving a value of better or worse, and (2) these are group observations, which neither means that all men or all women fit into this pattern, nor does it mean that there is something wrong when they do not. Moreover, hormones are not the only determinants for the above-mentioned aspects, as our culture, education, upbringing, norms, and values have also important influence.
4.3 Sexual Response
Sexual response (or sexual function) is the potency of the sexual machinery. It is a series of emotional and physical changes that occur when a person becomes sexually aroused and engages in sexually stimulating activities including intercourse and masturbation. In a simplified version we tend to say that there are three phases: sexual desire, sexual arousal, and orgasm. Originally, they were described as following each other in this order. That is what happens in many men. If not slowed down by the partner, many men tend to continue more or less as in a linear process from desire to arousal (horny and erection) and then orgasm/ejaculation as the rounding off. For many women it is rather different, as is seen especially in longer-standing heterosexual relationships. A common scenario is as follows: the man (with his higher T-level and accordingly more sexual desire) initiates erotic contact. The woman is not (yet) in the mood. When the man plays it well and pleases her enough, she will develop sexual excitement before achieving sexual desire. The “last” step of orgasm is also different for many women. Depending on mood and context of the moment she may like to have an orgasm, but many women can have full sexual satisfaction without having had an orgasm. This is difficult for many men, since their “function-oriented perspective” in some ways seems to dictate that his partner should have an orgasm. Combined with lack of good communication, this appears to be one of the reasons why some women fake an orgasm.
Context plays an important role in what will or will not happen, and this is far more relevant in women than in men.
We will discuss each of the three phases with special attention to the perspective of the cancer patient.
4.4 Sexual Desire
Although often called “butterflies in the belly,” sexual desire is situated in the brain. This part of sexuality is strongly guided by androgen hormones. In the upper range of serum concentration, the level of testosterone is said not to really correspond with the level of sexual desire. However, in the lower range (as regularly found after cancer treatment) T seems to be a very relevant element for sexual desire. There is much variety in desire. Proactive (or “spontaneous”) desire is the common pattern in about 75 % of men and in 15 % of women. Responsive desire is the common pattern in 5 % of men and in 30 % of women. Others will have mixed patterns and some 6 % of the women lack both spontaneous and responsive desire (existing independent of cancer) [1].
During the majority of time neither man nor women have sexual desire. The context should be good enough and they should be receptive in order to get “in the mood.” For this process a minimum amount of androgens seems necessary. Desire is also dependent on the neurotransmitter balance (with dopamine as desire-increasing factor and serotonin as desire-diminisher). Another relevant physical factor (or condition) for desire is energy. Next, one needs sufficient stimuli to get into the sexual mood. Here we see also male–female differences. Whereas for women relational stimuli are relatively more important, visual stimuli are far more relevant for both mainstream and gay men.
4.4.1 Sexual Excitement/Sexual Arousal
This phase is mainly guided by circulation. Arousal is partly a nongenital phenomenon (with increased pulse, blood pressure, breathing, and muscle tension). The genital part of arousal (erection and lubrication) is the result of hypercongestion of the penile and the perivaginal circulation.
In the man, the smooth muscles in the cavernous body relax and the intracavernous space fills with blood. Then, the veins are compressed so that the pressure increases, causing a “full penis.” Because the space is surrounded by the very tight tunica albuginea, when the pressure increases, the penis becomes hard and erect, because the space is surrounded by the very tight tunica albuginea.
In the woman, hypercongestion takes place in the clitoris and vessels surrounding the vagina with the consequence that fluid permeates through the vaginal wall. This lubrication has two functions. One is for fertility (with good lubrication favoring sperm survival). The other function is a mechanical one (“oiling the vaginal cylinder”), to prevent damaging the vaginal mucosa and to prevent pain during intercourse. So, proper circulation is a major condition for good arousal. The regulation of sexual arousal takes place via two centers in the spinal cord. These centers are also part of a reflex arc. Part of the erection and lubrication are the direct (reflex) result of genital stimulation.
For proper development of the arousal one needs good neural connections from the centers in the spinal cord to the external genitals. These nerves are located close to the prostate and the uterus. And finally, a complex interplay takes place between opening arteries, closing veins, and relaxing cavernous muscles. In that process nitric oxide and many other molecules, neurotransmitters and enzymes are involved in orchestrating the arterial vasodilation and venous vasoconstriction, with an important role for the endothelium.
In the excitement phase, testosterone has a small role via receptors in the brain, necessary for arousability (the ability to become “horny”).
4.4.2 Orgasm Phase
The major physical conditions for orgasm are intact nerves and a proper neurotransmitter balance. And, of course, proper stimulation.
In orgasm, there are also clear differences between the male and the female. Male: For many males, orgasm and ejaculation are experienced as the same. Whereas they always coincide in ±96 % of the men, the other 4 % of men have learned to have an orgasm without ejaculation (and they can have that several times consecutively).
After ejaculation, the man enters a refractory period (“falling in the black hole”). His system has to be “reset,” which can take 15 min in a young man and up to a full day in an aged man.
Female: Most women do not have such a refractory period. Besides, women can have orgasm in more different ways. Roughly, 90 % of the women can have an orgasm via stimulation of the clitoris; 25–35 % via stimulation (tapping the cervix and anterior vaginal wall) during penetration; some via fantasy only or via breast stimulation only. At least half of the women can have more than one orgasm in a row.
4.5 Androgens/Testosterone
In the context of this book, the role of androgens deserves extra attention because androgen levels are frequently disturbed by various cancer treatment strategies. Androgen deprivation treatment (ADT) for prostate cancer is a chemical way of castration. Whereas in ADT the castration is intended, most castration is an unintended side effect of treatment. That is the case in nearly all gynaecological cancers because surgical removal of the ovaries is part of the treatment. Total body irradiation and radiotherapy in the pelvic area can cause ovarian damage and testicular damage with permanent or temporary hypogonadism. This can happen also after extensive chemotherapy, as happens for instance in ovarian cancer and in blood and lymph cancer before stem cell transplantation. Radiotherapy and chemotherapy can also affect the adrenals, which during the woman’s fertile life are responsible for 50 % of her androgens.
Hypogonadism can also be found after high dose of opioids. Hypogonadism is the condition with too low gonadal hormones (testosterone).
Androgens are not only needed for sexual desire and arousability. They have many different functions. A substantial shortage of testosterone can be accompanied by a decrease in or loss of:
· Sexual desire
· Arousability (no more becoming horny)
· The ability and strength of orgasm (especially in women)
· Genital sexual sensations (“It is like dead flesh”)
· Spontaneous and sex-related erections
· Muscular strength (stamina)
· Bone density and muscle mass
· Mood
4.6 Sexual Dysfunctions
Disturbances of the sexual response usually are called sexual dysfunctions. There are many biological, psychological, relational, social, and cultural factors that have a role in causing, or maintaining a sexual dysfunction or in aggravating an existing one. With or without preexisting sexual dysfunctions there can be the consequences of cancer and its treatment.
In this chapter, we will address the more general aspects of sexual dysfunction, with some oncology relationships and in the next chapter we will more specifically address the oncologic relationships.
4.6.1 Sexual Desire Problems
In discussing desire, one has to acknowledge the importance of context. During the major part of the day, people have no sexual desire. Then, when one of a couple gets in the mood and invites action, the other is not always ready (or not yet ready) for action. This does not mean there is a desire problem. We should differentiate between sexual aversion (“I really don’t want to be involved”) and absence of desire (or no desire). The latter situation is very common in many situations of daily life. Clear examples are seen in mothers with young children.
Absence of sexual desire is normal when testosterone (T) has diminished. Several reasons for hypogonadism have been mentioned above.
Another reason for low desire is fatigue, a common complaint in many cancer patients. Fatigue can also be “caused” by low T. When faced with the combination of chronic fatigue and low sexual desire (as for instance frequently found after treatment for blood/lymph cancer) we should also consider lowered T as one of the causing factors, especially in persons who formerly experienced good desire.
Absence of proactive sexual desire can also be the side effect of neurotransmitter-influencing medication. Especially, SSRI and SNRI antidepressants are known to negatively influence sexual desire (and as a matter of fact, also the other phases of the sexual response). The group of paroxetin, citalopram, and venlafaxin (together representing more than half of all outpatient antidepressant prescriptions in many Western European countries) is known to negatively influence sexual desire in >60 % of patients [2].
Besides these physical killjoys, there are also emotional reasons. In a large meta-analysis, 38.2 % of cancer patients were found to suffer from depression, anxiety, adjustment disorder, or dysthymia [3]. These conditions will diminish desire for the majority of patients (although a small number of persons desire more sex when they get depressed).
The changed social situation can be another reason for low sexual desire. The partner will change as well. On the one hand, the diagnosis is a major life event accompanied by fear of loss. On the other hand, the caring role and taking over of many tasks that formerly were done by the patient can cause serious fatigue, leading to an absence of sexual initiative or seduction also from the partner’s side.
4.6.2 Arousal Problems
Arousability is a first condition for real arousal. Without sufficient androgens one cannot become “horny.” With regard to genital arousal problems there is a big difference between male and female. One could suspect that side effects of disease and medical intervention will give a more or less equal distribution between erectile dysfunction and lubrication dysfunction. However, the consequences are very different. When intercourse and penetration are very relevant in sex (which is true for many men), not having an erection usually means the end of sexual activity. “No lubrication,” on the other hand, is rather easily solved by some saliva, a lubricant, or some pain. In addition, “no erection” means for most men a serious damage to their male identity. That causes many men with erectile insecurity to completely stop making love to their partners and to avoid intimacy. The argument being: “Because I cannot finish the job properly!” (frequently meaning: I cannot give her sexual excitement or orgasm by penetration). In this way a sexual function problem can easily become a sexual relationship problem.
We will address only some of the more relevant possible reasons for arousal problems, starting with the nonorganic reasons, then the noncancer organic reasons, and then the potential cancer-related causes.
Nonorganic reasons. Many men grow up with a set of ideas on how sex should be. Some examples:
· Men are always ready and willing to have sex.
· The man is responsible for the woman’s sexual pleasure. So, he should be the initiator and the actor in bed.
· Sex requires an erection.
Such mental concepts neither create an attractive background for sexual fun, nor are they very reassuring for a pleasurable sexual encounter. Accordingly, they can cause a lot of nervousness and stress in men.
There are many noncancer-related organic reasons for erectile disturbances, especially in the population with chronic diseases. In the frontline are those conditions with high risk for cardiovascular disease (diabetes, dyslipidemia, metabolic syndrome, atherosclerosis, and hypertension) and many of the medications used for these conditions. Smoking, a rather typical male lifestyle factor, is accompanied by more ED, more COPD, and more lung cancer. And last but not least, obesity; it has become increasingly clear that a healthy lifestyle is not only good for the heart and weight, but also for erection.
The last decade showed an important change in the approach to erectile disturbance. Where “impotence” originally was a luxury problem, erectile disturbance now has become an indicator for a possible damaged cardiovascular condition.
In the process of cancer, diminished arousal can occur in several ways.
One of them is loss of erogenous zones as happens for instance after mastectomy in the women for whom breast stimulation was a prerequisite for arousal (and sometimes for orgasm).
The majority of cancer-related arousal disturbances happen in men because of damage to the nerves that guide the circulatory processes for erection. All interventions in the lower pelvis can cause such erectile dysfunction (ED). Radical surgery for prostate cancer, bladder cancer, and colorectal cancer is frequently accompanied by loss of erection, even in nerve-sparing surgery and the same happens in radiotherapy, although then the disturbance develops at a different pace. Whereas after surgery the erection nearly immediately comes to a standstill, radiation damage takes much longer and erection is gradually lost.
Erectile function can also disappear when the androgen levels go very low. A substantial amount of men with prostate cancer on androgen deprivation treatment have no erection.
4.6.3 Orgasm Problems/Ejaculation Problems
Outside of the medical context, the common orgasm problem in men is premature ejaculation, and in women, the inability to experience orgasm. Insufficient sexuality education / information can make women believe that they should orgasmduring penetration (according to the male scenario), which israther uncommon. So many women fake orgasm or run the risk of getting a problem. Lack of appropriate stimulation and not being able “to let go” are additional factors. Pain can be an inhibitor for such letting go.
The “letting go” inhibition can become stronger when it is accompanied by incontinence of urine or stool.
The adequate logistics for orgasm include proper innervation and a good neurotransmitter balance.
That is how for instance Multiple Sclerosis and the autonomic neuropathy of diabetes mellitus can cause anejaculation or retrograde ejaculation (where at orgasm the sperm disappears into the bladder). This can also happen after retroperitoneal surgery (for instance, for testicular tumors).
The majority of orgasm problems are caused by antidepressants and their influence on the neurotransmitter balance. SSRIs and SNRIs strongly influence orgasm. The group of most frequently prescribed antidepressants (venlafaxine, citalopram, and paroxetine) disturbs the orgasm capacity in 49–58 % of patients [2].
For many men, orgasm and ejaculation are experienced as one and the same. This is frequently confusing in pelvic cancer treatment, which usually is accompanied by loss of ejaculation. After radical surgery for prostate and bladder cancer there are no more organs to produce semen. Semen production disappears also without testosterone (as in androgen deprivation) and after pelvic radiotherapy.
Even without semen (i.e., without ejaculation) orgasm is possible, although it can be accompanied by pain or loss of urine (as happens after radical prostatectomy).
Prostate removal and radiotherapy also cause loss of the typical orgasm sensations for men who have had prostate stimulation in their love map.
Whereas radical pelvic surgery usually does not directly impair the orgasm capacity, it frequently indirectly has the same result when the treatment has shut down the erectile capacity. The average man at age 55 has experienced 4,500–6,500 orgasms, all with a good erection. With that experience it is very difficult to imagine still being able to get an orgasm, when erection is no more possible.
4.7 Epilogue
In this chapter, we have tried to illustrate in a simplified way the importance of many factors for normal sexual response. A set of healthy and properly functioning endocrine, circulatory, and nerve systems are mandatory for a well-functioning sexual response. Many factors involving cancer and its treatment can cause damage to these systems with profound consequences for the sexual life of the patient and the couple. Providing them before and during the treatment the right information about possible sexual consequences is an important step in the treatment of sexual concerns and sexual disturbances.
References
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Nagoski E. Come as you are. Simon & Schuster Paperbacks. 2015. p. 225.
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Serretti A, Chiesa A. Treatment-emergent sexual dysfunction related to antidepressants. A meta-analysis. J Clin Psychopharmacol. 2009;29:259–66.CrossRefPubMed
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Mitchell AJ, Chan M, Bhatti H, et al. Prevalence of depression, anxiety, and adjustment disorder in oncological, haematological, and palliative-care settings: a meta-analysis of 94 interview-based studies. Lancet Oncol. 2011;12:160–74.CrossRefPubMed