Penile cancer is fortunately rare, but the number of cases is increasing. Some experts predict a 77% increase in penile cancer by 2050.
Although developing countries have the highest rates of penile cancer, cases are increasing in most European countries. As the population ages, cases increase. Being over 50 is one of the main risk factors for penile cancer, and Europe has an aging population.
Other risk factors include a tight foreskin, poor genital hygiene and smoking. Penile cancer is rare in people who were circumcised at birth.
Squamous cells in the skin of the penis are responsible for more than 90% of penile cancers. Other malignancies, such as melanoma, basal cell carcinoma or sarcoma, are less common. Human papillomavirus (HPV) infection has been identified in approximately half of squamous cell cancer cases.
Papillomaviruses spread through skin-to-skin contact and are probably the most common sexually transmitted infection in humans. More than 70% of sexually active adults get papillomavirus infections, usually in adolescence.
Infections usually do not cause symptoms and can resolve within months to years without long-term complications. Previous HPV infection unfortunately does not appear to protect against future infections.
These infections can persist just beneath the skin’s surface. In the penis, this can lead to changes in skin texture and color – known as “precancerous changes.” A painless, symptomless ulcer or wart may develop, often on the glans and under the foreskin.
HPV 16, the most common type of high-risk HPV, can cause cancerous changes in tissues of the penis or cervix, mouth, throat, vulva, vagina and anus. It is probably the most cancer-causing HPV. Fortunately, HPV vaccines have already done a good job of reducing the risk of cervical cancer.
The effects of these injections on penile cancer will probably only become apparent after a long period of time, as there is usually a long time between the HPV infection and the development of the cancer.
Diagnosis of penile cancer is often delayed because patients feel guilty or ashamed. Many men report self-medicating with antimicrobial or steroid creams while putting off seeing a doctor.
Doctors also often contribute to delays because lesions are sometimes wrongly classified as benign. If malignant cells have spread to the lymph nodes in the groin, the chance of recovery is much smaller, so rapid diagnosis and treatment are important.
Therapy
Cancerous tissue can be successfully removed with laser or microsurgery. This can be combined with chemotherapy or radiotherapy. However, some tumors do not respond well to treatment and the penis may need to be amputated. But this is always a last resort.
A recent BBC report found that Brazil has one of the highest rates of penile amputations: almost two per day.
But there is hope on the horizon. New approaches, such as using engineered T cells (a type of immune cell) that attack HPV-infected cells, or immunotherapies such as tislelizumab that enhance immune responses to squamous cell tumors, have been shown to be effective in a few cases.
Colin Michie, Deputy Head, Faculty of Medicine, University of Central Lancashire
This article is republished from The Conversation under a Creative Commons license. Read the original article.