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Anal Cancer Symptoms: Early Signs and Warning Signals to Know
Anal cancer starts in the cells of the anus, which is the short tube at the end of the digestive system where stool leaves the body. It is a rare cancer. About 11,270 new cases will be diagnosed in the United States this year, with about 1,700 deaths. Knowing the symptoms of anal cancer can help you and your doctor catch it early, when it is easier to treat.
What Are the Signs and Symptoms of Anal Cancer?
Anal cancer can be tricky to notice at first. Many people do not have any symptoms in the early stages of the disease. According to the American Cancer Society, in its early stages, anal cancer may cause no noticeable symptoms at all. This is one reason the cancer can go undetected for a while. When symptoms do show up, they often look a lot like common, harmless problems such as hemorrhoids, anal fissures, or anal warts. Because of this overlap, people sometimes wait too long before seeing a doctor.
The most important thing to understand is that anal cancer symptoms are not unique to cancer. Almost every symptom linked to anal cancer, like bleeding or itching, is also caused by conditions that are not cancer at all. This does not mean you should ignore the symptoms. It means you should let a doctor figure out the actual cause instead of guessing on your own or assuming it is just hemorrhoids.
Anal cancer forms in the anal canal, which is lined with sensitive skin and tissue. Because this area has many nerve endings, tumors here can cause pain even when they are small. This is different from some other cancers, like early colon cancer, which often causes no pain at all. The location of anal cancer also means that symptoms tend to show up close to where the tumor is growing, rather than showing up somewhere else in the body first.
Doctors generally place anal cancer symptoms into groups. Some symptoms are common and show up in a large share of people who are later diagnosed. Other symptoms are less common but still worth knowing about. And if the cancer has spread beyond the anus, a different set of symptoms called advanced or metastatic symptoms can appear. This guide walks through each group so you know what to watch for at every stage.
It also helps to understand your own body and what is normal for you. Bowel habits can vary quite a bit from person to person. What matters most is a change from your normal pattern that lasts for more than a week or two. A single day of unusual bowel movements is rarely a reason for alarm, but a change that sticks around deserves attention.
Certain groups of people have a higher chance of developing anal cancer and should be extra alert to symptoms. According to the CDC and the American Cancer Society, this includes people:
Diagnosed with Human papillomavirus (HPV)
Diagnosed with HIV
Who have had an organ transplant and are taking medicines that suppress the immune system
Who smoke
Anal cancer is also more common in women than in men, and rates have been rising over time, especially among women, according to the American Cancer Society.
Age matters too. Most people diagnosed with anal cancer are older adults. The CDC reports that the average age at diagnosis is 63 for women and 62 for men, and the American Cancer Society notes the disease is rare in people under 35. Still, anal cancer can occur at younger ages, especially in people with HIV or a weakened immune system, so age alone should never be used to rule it out.
The bottom line from every major U.S. health organization, including the NCI, the American Cancer Society, and Mayo Clinic, is the same. If you notice any new or ongoing symptom in the anal area, especially one lasting more than a couple of weeks, see a doctor. Do not feel embarrassed. Doctors examine this part of the body all the time, and catching anal cancer early gives you the best chance for successful treatment.
What Are the Most Common Symptoms of Anal Cancer?
Bleeding: The single most common early symptom of anal cancer is rectal bleeding. Both the American Cancer Society and Cleveland Clinic identify bleeding from the anus or rectum as often being the very first sign that something is wrong. This bleeding is usually small in amount and may show up as bright red blood on toilet paper, in the toilet bowl, or mixed with stool. Because hemorrhoids also cause rectal bleeding, many people mistakenly assume that is the cause and delay seeing a doctor.
Pain or pressure: A very common symptom is pain or a feeling of pressure in the anal area. The NCI describes this as pain or pressure in the area around the anus. Some people describe it as a dull ache, while others feel a constant sense of fullness, almost like they need to have a bowel movement even right after they already have. Cleveland Clinic notes that people may feel like they are constantly needing to have a bowel movement even when their bowels are empty. This sensation can be uncomfortable and frustrating, and it often gets worse over time if the tumor grows.
A lump or mass: A physical sign is a lump or mass near the anus. This lump can sometimes be felt by touch, and it may be mistaken for a hemorrhoid or skin tag at first. The American Cancer Society specifically lists a lump or mass at the anal opening as a warning sign. Unlike a hemorrhoid, which tends to come and go or shrink over time, a cancerous lump usually does not go away on its own and may slowly get bigger.
Itching: also called anal itching or pruritus, is another frequent symptom. This itching can be persistent and hard to relieve with typical creams or hygiene changes. It happens because the tumor can irritate the surrounding skin and tissue. While anal itching has many harmless causes, such as irritation from wipes or minor skin conditions, itching that does not improve with basic care should be checked by a doctor.
Changes in bowel habits: This can include stools that are narrower or thinner than usual, changes in how often you have a bowel movement, or increased straining. A tumor growing in the anal canal can physically narrow the passage where stool exits the body, which is why some people notice their stool has become thinner, sometimes described as pencil thin.
Abnormal discharge: Discharge from the anus may be mucus-like or watery, and it can occur along with bleeding or on its own. Discharge happens because the tumor tissue can produce fluid or because the surface of the tumor may break down slightly, called ulceration, which can leak fluid.
Because these common symptoms- bleeding, pain, a lump, itching, bowel changes, and discharge- overlap so heavily with hemorrhoids and other benign anal conditions, doctors stress the importance of a proper exam rather than self-diagnosis. Mayo Clinic recommends making an appointment with a doctor if you have any of these symptoms and they are not going away, or if they worry you, even if you assume it is probably nothing serious.
What Are the Less Common Symptoms of Anal Cancer?
Not every symptom of anal cancer is common. Some symptoms show up less often but are still important to know about because they can be the only clue a person has. One less common symptom is loss of bowel control, also called stool or fecal incontinence. The American Cancer Society lists this as a possible sign of anal cancer. It can happen when a tumor affects the muscles that normally help control bowel movements, called the anal sphincter muscles.
Visible growth or sore: Another less common symptom is a visible growth or sore in the anal canal that a person or their doctor can see or feel during an exam. Mayo Clinic mentions a growth in the anal canal as a symptom people may notice. This growth may look like a wart, a lump, or an open sore, and it can sometimes bleed or become tender when touched.
Swollen lymph nodes: Some people notice swollen lymph nodes in the groin area, even before the cancer has clearly spread elsewhere in the body. The American Cancer Society notes that swollen lumps or lymph nodes in the anal or groin areas can be an early sign, because lymph nodes near the anus are often the first place cancer cells travel to from the original tumor. A swollen lymph node might feel like a firm, round bump under the skin in the groin.
Constipation: A persistent change in the shape and consistency of stool, beyond simple thinning, can also occur, though it is less commonly the very first symptom people report. This happens for similar reasons as thinning stool: the tumor is narrowing or partially blocking the anal canal, which makes passing stool more difficult over time.
Pain during bowel movements: Sharp or severe rather than a general dull ache during a bowel movement. While many anal conditions cause some discomfort with bowel movements, cancer-related pain can sometimes be more intense and may not improve with the usual remedies used for hemorrhoids or fissures, such as fiber, stool softeners, or topical creams.
Since anal cancer is strongly linked to HPV infection, some people first notice symptoms related to anal warts, called condylomas, that later change in appearance, such as growing larger, changing color, or starting to bleed or itch differently than before. Any anal wart that changes noticeably should be evaluated by a doctor, since this can occasionally signal that abnormal cells have developed into cancer.
Because these less common symptoms can be subtle or easy to explain away, the American Society of Colon and Rectal Surgeons and other U.S. medical groups emphasize that any unusual, persistent change in the anal area, no matter how minor it seems, deserves a medical evaluation, especially in people with known risk factors like HIV infection or a weakened immune system.
What Are the Symptoms of Advanced (Metastatic) Anal Cancer?
When anal cancer is caught early, it is often confined to the anal canal and nearby tissue. But if it is not found and treated in time, it can spread, or metastasize, to other parts of the body. According to the NCI, stage 4 anal cancer means the cancer has spread to distant organs such as the liver or lungs, in addition to possibly involving nearby lymph nodes. This stage requires different symptom awareness than earlier stages.
Swollen lymph nodes: One of the most noticeable signs of advanced anal cancer is swelling in the lymph nodes, particularly in the groin. As cancer cells travel through the lymphatic system, they often settle in lymph nodes first before spreading further. Swollen, firm lumps in the groin area that do not go away and are not caused by an infection can be a sign that the cancer has advanced beyond the anus itself.
Unexplained weight loss: is a common symptom of advanced cancer of many types, including anal cancer. When a person loses a noticeable amount of weight, generally more than 5 percent of their body weight, without trying to diet or exercise more, it can be a sign that the cancer is affecting the whole body, not just the anal area. This happens because cancer cells can change how the body uses energy and nutrients.
Ongoing fatigue: fatigue that does not improve with rest is another common symptom of advanced disease. This is different from feeling tired after a long day. Cancer-related fatigue tends to be persistent, can interfere with daily activities, and does not fully go away with sleep. It happens for several reasons, including the cancer itself, blood count changes, and the body's immune response to the tumor.
Pelvic pain: A more widespread or severe pain than earlier anal discomfort can develop if the cancer grows into nearby structures in the pelvis, such as muscles, nerves, or the bladder. This pain may feel different from the localized anal pain seen in earlier stages. It can be a deep, aching pain that is harder to pinpoint to one exact spot.
Pain or fullness in the upper right belly: If anal cancer spreads to the liver, a person may develop symptoms such as pain or fullness in the upper right side of the belly, yellowing of the skin or eyes, called jaundice, nausea, and loss of appetite. If it spreads to the lungs, symptoms can include a persistent cough, shortness of breath, or chest discomfort. These symptoms happen because tumors growing in the liver or lungs can interfere with how those organs normally work.
It is important to remember that these advanced symptoms usually develop after other, earlier warning signs have already been present for some time, often because those earlier symptoms went unnoticed or were mistaken for a minor problem like hemorrhoids. This is exactly why the NCI, American Cancer Society, and Mayo Clinic all stress the same message: do not wait. Persistent anal symptoms, even mild ones, should be checked by a doctor so that anal cancer, if present, can be found and treated at the earliest and most treatable stage possible.