Penile cancer is uncommon, particularly in Western societies. It is almost unknown in Jewish males who are circumcised soon after birth but is a little more common in Muslim males who are circumcised at about 10 or 12 years. Most that are seen are in uncircumcised men. Lack of genital hygiene and cleanliness may be a factor or sometimes this cancer is associated with the sexually transmitted human papillomavirus.

It is essentially a squamous cell cancer similar to the common skin cancers but somewhat more aggressive. It tends to spread rather more readily to draining lymph nodes in the groins than is usual for other squamous cancers of the skin.

Most cases are first seen when a small crusty, papillomatous or small ulcerated skin lesion is present, and these can usually be well treated by surgical removal of the lesion, keeping a close watch on draining groin lymph nodes thereafter. Occasionally very advanced cases are seen, usually in men living in remote places or undeveloped communities. These usually respond well to induction chemotherapy especially if given by intra-arterial infusion. Involved lymph nodes should be surgically resected. A series of quite spectacular responses of very advanced cancers on the penis have been reported from Taiwan using intra-arterial infusion chemotherapy, followed by surgery or radiotherapy. A high incidence of cure was reported.

Testicular tumours are not common but when they do occur they are almost always malignant. Most occur in young adult males between the ages of 18 and 40. They are almost all classified as “germ-cell” tumours. Germ cells are embryonic type cells capable of developing into different cell types. Germ-cell cancers are uncommon, but they occur most often in a testis. Occasionally they occur in midline structures like the mediastinum or retroperitoneum or pineal gland usually in children or young adults. Some cancers of the ovary are also germ-cell cancers.

There are no known causes of testicular cancer. They are more common in developed than developing countries but the reason for this is not known. They are distinctly more likely to occur in undescended testes. Cryptorchidism is a condition in which the testes have not descended from the abdomen, where they develop, into the scrotum where they should be present at birth. If one or both testes are not present in the scrotum of infant boys, they are retained in the abdomen or the inguinal canal or somewhere nearby. Surgical operation (orchidopexy) should be performed before the age of 8 or 10 to place the testes into their normal position. This will reduce the risk of development of testicular cancer sometime later in life, after puberty. It is postulated that the warmer temperature of the testes in the abdomen may be responsible for the increased risk of testicular cancer in undescended testes.

Similarly there is an increased risk in men with Klinefelter’s syndrome. This is an abnormal genetic condition in which rather than having XX or XY sex chromosomes, the affected individuals have three chromosomes, XXY. This gives some female characteristics in otherwise apparently tall, thin, underdeveloped males with small underdeveloped testes that are more prone to malignant change.

Cancer of the prostate is uncommon before the age of 45, but in Western countries, other than skin cancer, it is the most common cancer in men over the age of 65 and became increasingly common during the twentieth century, especially in the latter part of the twentieth century.

This rapid rise in recorded incidence is due in part to the use of the prostate-specific antigens (PSA) test for detecting early subclinical prostate cancers or “latent” prostate cancers that might not have otherwise progressed to a clinical stage. The rise in apparent incidence of prostate cancer after the common use of PSA as a screening test is somewhat similar to the increased numbers of early breast cancers in the 1980s and 1990s after common use of mammography as a screening test. However, the PSA test is much less specific for prostate cancer; a raised index simply indicates increased prostate cell activity that may be due to benign prostate disease, latent prostate cancer or established prostate cancer. Evidence suggests that early breast cancers are unlikely to remain “latent” for any length of time, but “latent” prostate cancer may well remain non-invasive indefinitely.

The cause of prostate cancer is largely unknown but its association with old age is illustrated by the fact that in Western countries almost all men over the age of 90 have microscopic evidence of at least early prostate cancer.

There is a familial association of prostate cancer especially in younger men (below 55 years) and some of these are linked to mutations of the BRCA2 gene (see Sects. 2.​4 and 2.​5). The increased familial association is greater if male relatives have had prostate cancer, but there is also some increase in families with a high incidence in men on the mothers’ side of the family.

There is also an increased risk in men with a history of prostatitis.

Prostate cancer is now the second most common cancer in males in Western countries, after skin cancers, and it is second only to lung cancer as a cause of cancer death in men. In stark contrast epidemiological studies show that Asians, Africans and native Americans living in their traditional lifestyles have a low incidence of prostate cancer (see Appendix and Table 1).

The highest incidence is in black males in the United States followed by white males in the United States, Europe and other Western countries. The lowest incidence of prostate cancer is in men in India and Southeast Asia and also in black males living in Africa. Men of Asian or African ethnicity who have lived all their lives in Western countries have a high risk and in Afro-Americans an even higher risk than in white males of those countries. This suggests that causes are more closely related to environmental factors rather than racial or genetic factors. It is likely that differences in diet may play a part because prostate cancer is less common in communities that have predominantly vegetarian diets.