Anal cancer is a relatively uncommon disease involving the growth of abnormal cells in the tissues of the anal canal or the surrounding perianal skin. Most cases are classified as squamous cell carcinomas, which arise from the flat cells lining the anal canal. The symptoms associated with this condition are often general and can mimic much more frequent, non-cancerous issues, such as hemorrhoids or anal fissures. This overlap can make the condition difficult to identify in its early stages, sometimes causing a delay in seeking medical evaluation. Anyone who notices persistent changes in the anal area should consult a healthcare provider for a thorough examination.
Observable Physical Manifestations
The most direct physical sign of anal cancer involves the appearance of abnormal growths or changes in the tissue texture. A common manifestation is a lump or mass found either just inside the anal opening or on the external skin. These lumps tend to feel firm and are often irregular in shape, distinguishing them from the typically softer, more rubbery feel of a prolapsed hemorrhoid.
These growths can vary significantly in size, sometimes starting as small nodules that increase over time. In addition to a mass, the cancer may manifest as a sore or ulcer that does not heal despite typical care measures. This non-healing wound can occur on the perianal skin and may be mistaken for a stubborn fissure or skin irritation.
Another physical presentation involves a noticeable change in the skin’s texture around the anus, which may include thickening of the tissue. Lesions that look somewhat like warts may also be present. These wart-like growths, sometimes caused by the human papillomavirus (HPV), can be precursors to anal cancer. Any persistent, palpable change in the anal tissue warrants professional examination to determine its underlying cause.
Associated Non-Visual Symptoms
Many patients first notice subjective symptoms that are not visible upon casual inspection. Persistent anal bleeding is a frequent initial symptom, although its appearance can vary. The blood may be bright red, similar to that from hemorrhoids, or it may appear darker, often occurring during or after a bowel movement.
Patients may experience chronic pain, discomfort, or a feeling of pressure in the anal or rectal area. Unlike the sharp pain of an anal fissure, cancer-related pain may be more persistent and progressive. This discomfort can be accompanied by an unusual discharge from the anus, which may be mucus, pus, or fluid mixed with blood.
Persistent anal itching, medically termed pruritus ani, is another common symptom. Other signs involve changes to normal bowel habits, such as a change in stool consistency or frequency. This can manifest as persistent diarrhea or constipation, or the stools may become noticeably thinner, suggesting the presence of a mass narrowing the anal canal.
Why Self-Diagnosis Is Difficult
The challenge in identifying anal cancer stems from the fact that nearly all its symptoms overlap with common, benign conditions. For instance, the bleeding and lumps that characterize anal cancer are also the primary signs of hemorrhoids, which are vastly more common in the general population. Hemorrhoids are swollen blood vessels that typically present as soft lumps and cause intermittent bright red bleeding, often linked to straining.
Conversely, an anal cancer lump is more likely to be firm, irregular, and cause continuous symptoms rather than resolving with home treatment. Similarly, the pain and bleeding associated with an anal fissure, a small tear in the lining, can be confused with a cancerous lesion. Anal fissures typically cause sharp pain during defecation, whereas cancer-related pain is often more constant and deep-seated.
The initial assumption of a benign condition, even by medical professionals, is common, with studies showing that anal cancer is sometimes initially misdiagnosed as hemorrhoids. This symptom mimicry means that relying on self-assessment is inherently unreliable. The persistence of symptoms, or their worsening over time, is the most reliable indication that a professional evaluation is necessary, regardless of the initial suspected cause.
Confirming the Diagnosis
Since symptoms alone cannot definitively distinguish between a benign condition and cancer, a medical evaluation is required to confirm the diagnosis. The process typically begins with a physical examination, including a Digital Rectal Exam (DRE). A gloved finger is inserted into the anus to feel for any abnormal masses, nodules, or areas of tenderness within the anal canal. The physician will also visually inspect the perianal skin for any growths or non-healing sores.
If a suspicious area is detected, further examination using specialized instruments is often performed. An anoscopy uses a short, rigid tube with a light source to allow the physician to visually inspect the anal canal lining in detail. This procedure helps to locate and characterize any lesions that might be too high to be felt easily during a DRE.
The definitive step for confirming anal cancer is a biopsy, which involves removing a small sample of the suspicious tissue. This sample is then sent to a pathology lab where it is examined under a microscope for the presence of malignant cells. This microscopic analysis establishes a conclusive diagnosis and determines the specific type of cancer present, guiding all subsequent treatment decisions.