Penile carcinoma is a malignancy that develops in the cells of the penis. This cancer is uncommon in North America and Europe, accounting for less than 1% of cancers in men, but is more frequent in some regions of South America, Africa, and Asia. The disease often begins in the skin cells and can progress to involve deeper tissues.
Recognizing Penile Carcinoma
The initial signs of penile carcinoma involve visible changes to the penis, such as a growth or sore on the glans, foreskin, or shaft that does not heal. Other symptoms include bleeding, a foul-smelling discharge, thickening or color changes of the skin, a rash, or small crusty bumps. Swelling at the tip of the penis can also occur, and in some cases, it may become difficult to retract the foreskin (phimosis). The persistence of these signs warrants a professional evaluation.
Approximately 95% of penile cancers are squamous cell carcinomas (SCC), which originate in the flat skin cells covering the penis. An early form is carcinoma in situ (CIS), where abnormal cells are confined to the top skin layer.
Rarer types of penile cancer exist. Melanoma of the penis develops from pigment-producing cells and is often more aggressive. Basal cell carcinoma (BCC) is a slow-growing cancer that begins in deeper skin layers. Sarcomas, which form in connective tissues, and adenocarcinoma, which starts in sweat glands, are exceptionally uncommon.
Underlying Causes and Risk Factors
Infection with certain types of the human papillomavirus (HPV) is a primary contributor. Strains like HPV-16 and HPV-18 are found in about half of all cases. HPV is a common virus transmitted through skin-to-skin contact.
Phimosis, a condition where the foreskin is too tight to be pulled back, is a risk factor. It can lead to the accumulation of smegma (a substance of dead skin cells and oils), causing chronic inflammation that may increase cancer risk. Men who are not circumcised and have poor hygiene are at higher risk.
Other risk factors include:
- Smoking, as chemicals in tobacco can damage cell DNA.
- Age, with the disease being most common in men over 50.
- A weakened immune system, such as in individuals with HIV.
- A history of psoriasis treatment involving psoralen and ultraviolet A (PUVA) light.
The Diagnostic Pathway
Diagnosing penile carcinoma begins with a physical examination. A physician inspects the genital area for abnormalities, feels the groin’s lymph nodes for swelling, and takes a detailed medical history, inquiring about symptoms and risk factors.
If cancer is suspected, a biopsy is the definitive diagnostic step. This procedure involves removing a small sample of the suspicious tissue for microscopic analysis by a pathologist. An incisional biopsy takes a piece of a larger lesion, while an excisional biopsy removes the entire abnormal area. The biopsy confirms the presence and type of cancer cells.
After diagnosis, imaging tests are used for staging to determine if the cancer has spread. An ultrasound can help show how deeply the tumor has grown into the penis. A CT scan or an MRI may be used for a more detailed view and to check for spread to lymph nodes or other organs. An MRI can be effective at imaging soft tissues, sometimes requiring an injection to make the penis erect for clearer pictures.
Treatment Modalities Based on Staging
Treatment for penile carcinoma depends on the cancer’s stage, which is determined by the tumor’s size and how far it has spread.
Early-Stage and Topical Treatments
For early-stage cancers confined to the top skin layers (carcinoma in situ or CIS), less invasive options are used. Topical therapies, like 5-fluorouracil (5-FU) cream or imiquimod, are applied to the skin to destroy cancer cells. Laser ablation uses a focused light beam to burn away cancerous tissue and is another option for superficial lesions.
Surgical Options
Surgery is the most common treatment, with the procedure type depending on the tumor’s size and location. For cancers limited to the foreskin, a circumcision may be sufficient. A wide local excision removes the tumor along with a margin of healthy tissue. Mohs surgery is a precise technique where thin layers of tissue are removed and examined one at a time until no cancer cells remain.
For larger tumors, a partial penectomy removes the end of the penis, while a total penectomy involves removing the entire organ. In cases of a total penectomy, a new opening for urination (a perineal urethrostomy) is created.
Treatments for Advanced or Spread Cancer
Lymph node dissection (surgical removal of groin lymph nodes) is often performed if cancer spread is suspected. This procedure helps with staging and disease control.
Radiation therapy uses high-energy x-rays to kill cancer cells. It can be a primary treatment for early-stage cancers to preserve the penis or used after surgery (adjuvant therapy) to eliminate remaining cells. Radiation can be delivered externally or internally through brachytherapy, where a radioactive source is placed near the tumor.
For advanced cancer that has metastasized to distant organs, systemic chemotherapy is the primary treatment. Chemotherapy drugs travel through the bloodstream to destroy cancer cells throughout the body. While it can help manage the cancer and relieve symptoms, it is unlikely to cure stage IV disease.