Diagnosing penile squamous cell carcinoma is a multi-step process that combines clinical examination, tissue analysis, and advanced imaging to determine the presence and extent of the disease. Early detection through prompt medical evaluation of suspicious penile lesions can significantly improve treatment outcomes and quality of life.
Introduction: Who Should Seek Diagnostic Evaluation
Any man who notices unusual changes in his penis should seek medical attention without delay. Many men feel embarrassed about penile problems and may postpone seeing a doctor, but this hesitation can allow cancer to progress to more advanced stages. Early diagnosis is absolutely critical because penile cancer caught in its early stages is much more treatable and often curable, while cancer that has spread to other parts of the body becomes significantly harder to manage.[1][2]
Diagnostic evaluation is advisable when any of several warning signs appear. These include a painless lump or sore on the penis that may bleed, changes in skin color or texture, small crusty bumps, flat growths with a bluish-brown appearance, thickening of the skin, a persistent rash, or swelling and irritation particularly around the head of the penis. Some men also notice foul-smelling discharge underneath the foreskin. While these symptoms can be caused by less serious conditions like infections or allergic reactions, only a healthcare provider can determine whether cancer is present.[2][8]
Men who are at higher risk should be especially vigilant about seeking evaluation. Risk factors include being over 55 years of age (about 80% of diagnoses occur in this age range), being uncircumcised, having human papillomavirus (HPV) infection, poor genital hygiene, chronic inflammation of the penis, conditions like phimosis where the foreskin cannot be pulled back, tobacco use, and having HIV or AIDS. However, anyone with suspicious penile changes should be evaluated regardless of whether they have known risk factors.[2][10]
Classic Diagnostic Methods
Physical Examination
The diagnostic process begins with a thorough physical examination by a healthcare provider. The doctor will carefully examine the entire penis, including the shaft, the head (called the glans), and if the patient is uncircumcised, the foreskin. They will look for any visible abnormalities such as sores, lumps, discoloration, thickening of tissue, or other changes in the skin. The examination also includes checking for any discharge or unusual odors that might be present.[8][13]
A critical part of the physical examination involves palpating, or feeling, the lymph nodes in the groin area. This is because penile squamous cell carcinoma has a strong tendency to spread through the lymphatic system to nearby lymph nodes. The doctor will carefully feel both sides of the groin to detect any enlarged or abnormal lymph nodes. Lymph nodes can become swollen for many reasons including infection, and they may remain enlarged long after an infection has resolved, so finding swollen nodes doesn’t automatically mean cancer has spread. However, their condition provides important information for staging the disease.[9][13]
Biopsy: The Definitive Diagnostic Test
While physical examination can raise suspicion of penile cancer, a biopsy is absolutely essential to confirm the diagnosis. A biopsy involves removing a small sample of tissue from the suspicious area so it can be examined under a microscope by a specialist called a pathologist. This is the only way to definitively determine whether cancer cells are present, what type of cancer it is, and how aggressive it appears to be.[8][9]
Several types of biopsy techniques may be used depending on the location and size of the lesion. A punch biopsy uses a circular blade to remove a small cylindrical sample of tissue. An incisional biopsy removes just a portion of the suspicious lesion, while an excisional biopsy attempts to remove the entire lesion along with some surrounding normal tissue. Whenever possible, the doctor will try to sample tissue from underneath the lesion as well as the surface, because this provides information about how deeply the cancer may have invaded.[8]
The pathologist examines the biopsy sample to identify the specific type of cancer cells present. About 95% of penile cancers are squamous cell carcinomas, meaning they originate in the flat, thin cells that line the surface of the penis. The pathologist also assigns a grade to the cancer, which describes how abnormal the cells look and how aggressively they appear to be growing. Grade 1 cancer cells look very similar to normal cells and tend to grow slowly, while grade 3 cells look very abnormal and tend to grow more quickly.[4][6]
Imaging Studies for Staging
Once penile cancer has been confirmed through biopsy, imaging tests help determine the extent of the disease. These studies show whether the cancer has invaded deeper structures, spread to lymph nodes, or traveled to distant parts of the body. This process is called staging, and it guides treatment decisions.[8]
Ultrasound may be used to evaluate the primary tumor and to examine the groin lymph nodes. During an ultrasound, sound waves create images of the internal structures. For penile cancer, ultrasound can help determine how deeply the tumor has invaded into the tissues of the penis. It can also identify suspicious lymph nodes in the groin, and when combined with fine needle aspiration (inserting a thin needle to collect cells), it can help determine whether the nodes contain cancer cells.[13]
Computed tomography (CT) scans or magnetic resonance imaging (MRI) provide detailed cross-sectional images of the body. These scans help doctors see whether cancer has invaded the deeper structures of the penis (the erectile tissue called the corpora cavernosa), and they evaluate lymph nodes in the groin and pelvis. CT and MRI are particularly useful for assessing the extent of disease in patients with more advanced cancer.[8][13]
In some cases, especially when lymph node involvement is suspected or confirmed, doctors may order a PET-CT scan. Positron emission tomography (PET) combined with CT provides both anatomical and metabolic information. Cancer cells typically show increased metabolic activity, which shows up on PET scans. This test is particularly helpful for detecting cancer spread to deep pelvic lymph nodes or distant organs.[9]
Assessment of Lymph Node Involvement
Evaluating whether cancer has spread to the lymph nodes is one of the most critical aspects of diagnosing penile cancer. The status of the lymph nodes is the strongest predictor of survival, so accurate assessment is essential. Many patients have enlarged lymph nodes at the time of diagnosis, but this doesn’t always mean cancer is present, as infection and inflammation can also cause swelling.[13][15]
When lymph nodes cannot be felt during physical examination but the primary tumor has features suggesting a higher risk of spread, doctors may recommend a procedure called dynamic sentinel lymph node biopsy. In this technique, a small amount of radioactive material is injected into or near the tumor. This substance travels through the lymphatic system to the first lymph nodes that drain the area (called sentinel nodes). These nodes are then identified, removed surgically, and carefully examined under a microscope. If the sentinel nodes are free of cancer, the likelihood of cancer in other lymph nodes is very low, potentially sparing the patient from more extensive surgery.[13]
For patients with clearly enlarged or suspicious lymph nodes, fine needle aspiration may be performed. A thin needle is inserted into the node to withdraw cells, which are then examined microscopically. If cancer cells are found, this confirms that the disease has spread to the lymph nodes. In other cases, surgical removal and examination of the lymph nodes may be necessary to definitively determine whether they contain cancer.[13]
Diagnostics for Clinical Trial Qualification
When patients are being considered for enrollment in clinical trials testing new treatments for penile squamous cell carcinoma, they must undergo specific diagnostic procedures to determine eligibility. Clinical trials have strict entry criteria to ensure that participants are appropriate for the experimental treatment being studied and that results can be interpreted accurately.
Tissue samples obtained from biopsy are essential for clinical trial participation. The pathology report must confirm the diagnosis of squamous cell carcinoma and provide detailed information about the cancer’s characteristics. Trials may require specific information about tumor grade, depth of invasion, and whether HPV is present in the tumor tissue. HPV testing of the tumor is increasingly important because HPV-positive penile cancers may behave differently and respond differently to certain treatments than HPV-negative cancers.[1][6]
Accurate staging through imaging studies is crucial for trial eligibility. Most clinical trials enroll patients at specific stages of disease. For example, a trial might specifically target patients with lymph node involvement or those with distant metastases. Therefore, comprehensive imaging with CT or MRI of the pelvis and abdomen, and sometimes PET-CT scans, may be required to precisely determine the extent of disease before enrollment.[9]
Baseline laboratory tests are standard requirements for clinical trial participation. Blood tests assess overall health, organ function, and help establish a starting point for monitoring side effects. Common tests include complete blood counts to evaluate red blood cells, white blood cells, and platelets; tests of liver function (measuring enzymes and proteins produced by the liver); kidney function tests (measuring creatinine and blood urea nitrogen); and general chemistry panels. These results help determine if a patient is healthy enough to tolerate the experimental treatment.[9]
Performance status assessment is another key criterion. Doctors use standardized scales to evaluate how well a patient can perform daily activities and how much the cancer affects their functioning. This information helps predict whether a patient can tolerate treatment and complete the trial protocol. Patients who are very debilitated may not be eligible for trials testing intensive therapies.
