I have written many entries over the years, covering a variety of urological and general health topics, some trivial and others more consequential. Today’s topic is of particular importance because many people are unaware of the potential cancer consequences of sex, are uninformed about the current epidemic of sexually-transmitted throat and tongue cancers in baby boomer men, and most importantly are not knowledgeable of the fact that these cancers are preventable through a vaccination that is FDA-approved for both genders. The message conveyed in today’s entry about viral-induced cancer needs to go viral, so please spread the word and forward this entry to your relatives, friends, and co-workers, particularly to those under 45 years of age, the demographic approved to be recipients of the vaccine.

I was prompted to write this entry because I recently treated a patient with penile cancer whose wife is a survivor of vulvar cancer. Both the penile and vulvar cancers were likely caused by human papilloma virus (HPV) infection.

Sex is necessary for procreation and also serves as a vital recreational activity. The dark side is that it incurs the risk of sexually transmitted infections, but even more consequentially, sexually transmitted cancers. HPV can be transmitted by genital-genital intercourse, genital-anal intercourse, oral-genital intercourse, manual-genital contact, oral-anal contact, and even oral-oral contact (open mouth kissing), virtually any permutation of oral, genital, manual and anal contact. Penetrative intercourse is not necessary to acquire an HPV infection. Years after exposure, these viruses are capable of transforming healthy cells into cancerous cells, giving rise to cervical, vaginal, vulvar, penile, anal, and oropharyngeal cancers. The great news is that there is a vaccine available (FDA approved for adults up to age 45) that can prevent HPV sexually transmitted infections and HPV sexually transmitted cancer.

HPV Basics

(HPV) is the name given to a group of viruses that are transmitted by skin-to-skin or mucosa-to-mucosa contact of the genitals, anus and the oropharynx, entering the body via skin or mucosal trauma, and not via an exchange of bodily fluids.  H–> human; P–> papilloma = wart like growth; V–> virus. Certain HPV types cause common and plantar warts, others cause genital, perineal and anal warts (anogenital warts), and yet other types cause a variety of cancers.

HPV is the most common sexually transmitted infection in the United States, prevalent in about 45% of adult men and 40% of adult women. Most infections cause no symptoms and disappear without treatment. An estimated 80% of sexually active people contract HPV at some point in their lives with about 15 million new infections annually in the USA. 80 million or so people are thought to have an active HPV infection at any given time. When symptomatic, HPV is characterized by genital warts (condyloma) in the anogenital regions. Aside from infecting the genital and anal areas, the mouth, throat, and even the respiratory tract are potential sites of infection. HPV has been associated as a causal agent for cervical, penile, vaginal, vulvar, anal, and oropharyngeal cancers.

The 3 Types of HPV Infections

Infections can be characterized as latent, sub-clinical or clinical.

Latent HPV infections are the most common type: asymptomatic, transient, self-limited, unrecognized and detectable only by tests for viral DNA, but transmissible to sexual partners. Latent HPV infections are often neutralized or made dormant by the immune system for significant periods of time, only to be later unknowingly transmitted to another sexual partner, including a spouse. The uncertainty over “who” is responsible for transmission of the HPV and “when” the infection occurred can be a source of great anxiety for a couple when one partner becomes aware that they are infected. It is extremely difficult to source the origin of any HPV infection since the virus can remain dormant for years.

Sub-clinical HPV infections are identified only after careful inspection of the anogenital regions of the body following the application of acetic acid, which causes the lesions to appear white.

Clinical HPV infections cause visibly apparent wart-like lesions of the ano-genital area, known as condyloma, the vast majority of which are caused by HPV-6 and HPV-11. These viral types have also been associated with conjunctival, nasal, oral, and laryngeal warts. These are not the types that cause cancer. Ano-genital warts are typically flat, raised, or stalk-like often reddish-brown growths on the genitals, particularly under the foreskin of the uncircumcised penis, on the shaft of the circumcised penis and on the vulva. They can also occur in the groin, pubic region, scrotum, perineum, urethra, vagina, cervix and anus. They are usually asymptomatic, but can occasionally be itchy or painful depending upon their size and location.  In men, these are usually obvious since they typically occur externally on the skin of the penis, pubic area, scrotum, perineum and anal regions. On occasion they can occur within the urethra, the channel that conducts urine through the penis. When left untreated, they can enlarge significantly into cauliflower-like, variable size lesions. In females, they are obvious when on the vulva, but they can also occur in a hidden nook of the vagina or within the cervix, which can make identification challenging. The diagnosis of ano-genital warts is often obvious by visual inspection and can be confirmed by biopsy. If left untreated, warts can remain stable, increase in size and number, and sometimes regress and resolve.

HPV-induced Cancers

Oncogenic types of HPV can give rise to cancer of the cervix, vagina, vulva, penis, anus and oropharynx. HPV-16 and HPV-18 are the types that most commonly cause cancer. HPV is estimated to be responsible for 7-8% of all human malignancies.

Virtually all cervical cancers are caused by HPV. HPV gives rise to abnormal cervical cell changes (dysplasia) that can ultimately lead to cancer. Cervical cancer is completely preventable if precancerous cell changes are identified and treated early, before cervical cancer develops. Diagnostic regimens use cervical Pap smears, HPV DNA testing, and colposcopy (visual inspection of the vagina with magnification). Cervical cancer has been the most studied of all the varieties of cancer that HPV can cause and was the first cancer in females to be identified as being caused exclusively by a viral infection.

Trivia Tidbit: The association between HPV and cervical cancer was demonstrated by a German virologist, Harald zur Hausen, who was awarded the Nobel Prize in Medicine in 2008 for his work.

75% of vaginal cancers are caused by HPV, as are 70% of vulvar cancers. Over 60% of penile cancers and more than 90% of anal cancers are caused by HPV. 70% of oropharyngeal cancers (throat, tonsils, base of tongue) are caused by HPV. The survival rate of HPV-related oropharyngeal cancers is much better than for that of tobacco-related oropharyngeal squamous cell cancers that are not HPV-related.

Currently, oropharyngeal cancers are the most common HPV-related cancer in the USA. The last few years have witnessed an alarming increase in the incidence of HPV-related oropharyngeal cancers, particularly in men of the baby boomer generation. Unfortunately, the HPV vaccine–with the potential to prevent the occurrence of oropharyngeal HPV infections and thus tongue, throat and tonsillar cancers–was not available to the baby boomer generation. This surge in mouth and throat cancers in baby boomer men is caused by chronic HPV infections brought on by oral sex.

How HPV Causes Cancer

After an oncogenic type of HPV infects cells of the skin or mucus membranes, HPV DNA (deoxyribonucleic acid) becomes incorporated into the host cells’ DNA and the virus proliferates. This sabotage of the host cells’ DNA with permanent mutations in the DNA sequence can lead to the uncontrolled and disorganized growth of abnormal cells. Host cells are transformed into a growing and destructive version of their former selves. These abnormal cells can then divide and proliferate aberrantly and without control. Under normal circumstances, the body repairs damaged DNA, but with cancer cells the damaged DNA is unable to be repaired. This process leading from normal cells to precancerous cells to cancerous cells can take 10-20 years or longer.

SEX- –> HPV INFECTION (OFTEN ASYMPTOMATIC) —> DYSPLASIA (ABNORMAL GROWTH) —> CANCER

HPV Vaccination 

The HPV vaccine was developed in Australia at the University of Queensland by Ian Frazer and Jian Zhou. In 2006, Gardasil–-the first HPV preventive vaccine– was marketed by Merck. It was not until 2014 that it was approved by the FDA in the USA.

vaccination is a potent tool to prevent HPV-related cancers and ano-genital warts. In Australia, due to the effectiveness of vaccination and screening, cervical cancer mortality is almost zero. It is important to know that the vaccine does NOT treat existing HPV or genital warts.

HPV 6/11/16/18/31/33/45/52/58 Gardasil 9 (Merck)–the only formulation available in the United States– protects against nine HPV types including the types most commonly associated with anogenital warts and cancer.

All boys and girls age 11-12 are recommended to receive the HPV vaccines prior to the onset of sexual activity. A two-dose schedule is recommended for those initiating the vaccination prior to their 15^th birthday, whereas a three-dose schedule is recommended for those receiving the vaccination after their 15^th birthday. The vaccines protect against HPV for at least 6 years.

The Gardasil 9 vaccine is FDA-approved for females age 9-45 for the prevention of cervical, vulvar, vaginal, and anal cancers caused by HPV types 16, 18, 31, 33, 45, 52, and 58; precancerous or dysplastic lesions caused by HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58; and genital warts caused by HPV types 6 and 11. The same vaccine is FDA-approved for males age 9- 45 for the prevention of anal cancer caused by HPV Types 16, 18, 31, 33, 45, 52, and 58; precancerous or dysplastic lesions caused by HPV Types 6, 11, 16, 18, 31, 33, 45, 52, and 58; and genital warts caused by HPV Types 6 and 11. The cost of Gardasil fully covered by private and public insurance.

Bottom Line: HPV is a potentially harmful infection because of the possible development of viral-induced cancers years after the initial infection. There has been a recent surge in HPV-related mouth, tongue and throat cancers with the HPV contracted from oral sex, particularly in males of the baby boomer demographic. The availability of the HPV vaccination that can be given to adults up to age 45 represents a major public health triumph that is capable of preventing this scourge.

Zimmerman’s Law: Nobody notices when things go right. Public health science has been a victim of its own success, since there is little appreciation or even consideration of diseases that we never get. Do you really appreciate the smallpox infection that did not kill you, the scrape that did not cause a life-threatening bacterial infection, or the tap water that did not contaminate you with cholera? Steven Johnson, in “How Humanity Gave Itself an Extra Life” (NY Times magazine, May 2, 2021) refers to an “invisible shield” that has been built incrementally over the last few centuries, keeping us safer from death–including vaccines, antibiotics, chlorine in the drinking water, medical scientific breakthroughs, etc. Vaccination against HPV is now part of the “invisible shield” that can prevent cancers of the vulva, vagina, cervix, penis, anus and oropharynx. KUDOS to public health science!