Syphilis and the risk of penis cancer

Until recently, syphilis was considered a major cause of penis cancer. The possible role of syphilis was discarded without much debate with the detection of certain of human papillomaviruses centrally involved in the etiology of penis cancer.

To reevaluate the association between syphilis and penis cancer by using truly population-based cancer and syphilis data and to generate a more sound basis for judging the possible role of syphilis in the etiology of penis cancer.

Patients with epidermoid cancer of the penis, totalling 1,523, were diagnosed and reported to the Danish Cancer Registry from 1943 to 1990. Through linkage with the Danish Syphilis Registry, the impact of prior syphilis infection was evaluated in a case-control design using patients with colon cancer or stomach cancer as controls.

Depending on the criteria used to assess prior syphilis status, 3% to 5% of patients with penis cancer had had syphilis before the cancer diagnosis. The corresponding proportions were 2% to 4% among patients with colon cancer and 2% to 5% among patients with stomach cancer. Logistic regression showed that patients with penis cancer did not have a syphilis history significantly more often than control cancer patients.

Syphilis should be removed from the list of possible causes of penis cancer.