Anal cancer is a rare yet concerning gastrointestinal cancer that affects the rectum and anal canal. From 2001-2015, studies found that anal cancer rates and mortality increased at an alarming rate. Moreover, the American Cancer Society predicted that approximately 9,760 new cases of anal cancer and 1,870 deaths were expected by the end of 2023.
In this article, we’ll discuss common anal cancer symptoms and differences between anal cancer and other gastrointestinal diseases like colon cancer. We’ll uncover the reasons behind the rising incidence rates and how you can reduce your risk of developing this disease.
Below are some common anal cancer symptoms that you should know. Be sure to see a doctor if any symptoms persist.
Rectal bleeding: Blood in the stool that ranges from bright red to dark. It can also be noticed on toilet paper after wiping. It's a common symptom and not always indicative of cancer, but you should see your doctor if you have persistent bleeding.
Anal pain or discomfort: Persistent or recurring pain in the anal area, which might be constant or occur during bowel movements. This pain can range from mild to severe.
Changes in bowel habits: This includes any noticeable alteration in bowel patterns, such as diarrhea, constipation, or changes in stool consistency and frequency. It might also include a feeling that the bowel isn’t empty.
Anal itching: A continuous itch around the anus, often uncomfortable and persistent. Other issues, such as hemorrhoids, can also cause this symptom.
Swelling or lumps near the anus: Detection of a lump or masses near the anus. These could be tender or painless.
Unusual discharge from the anus: The presence of unusual mucus or pus-like discharge from the anus, which is not typical for regular bowel movements.
Narrowing of stool: Changes in the size or shape of stool, often becoming thinner than usual, which can indicate a blockage or growth in the anal canal.
A feeling of fullness in the anal area or rectum: This is a sensation of incomplete evacuation after a bowel movement or a constant feeling of fullness in the rectum.
Anal incontinence: This refers to the loss of control over bowel movements leading to unintentional passing of stool.
The colon, rectum, and anus are distinct anatomical regions within the gastrointestinal system. Also known as the large intestine, the colon is a long, tubular organ that absorbs water and electrolytes from digested food. The rectum is a short tube that connects the large intestine and anus, while the anus itself is a short tube that connects the rectum to the outside of the body.
Colorectal cancers are more common than anal cancer and more likely to become malignant – meaning it gets worse over time. Precancerous lesions may start as polyps that become cancerous over months or years. Anal cancer starts in the anal canal and is overwhelmingly caused by the human papillomavirus (HPV).
Symptoms also vary between the two. Colorectal cancer may feel like pressure in the region accompanied by a sensation that the bowel doesn't empty during a bowel movement. Other general signs include weakness, fatigue, and losing weight without trying. Anal cancer may manifest as itching, pain, or bleeding.
Currently, HPV is the most common STD in the world, but most people aren’t even aware they have it. The virus is spread through intimate skin-to-skin contact. Over 90% of anal cancer is caused by HPV. Both new cases and deaths from anal cancer are increasing. You can get HPV by having vaginal, anal, or oral sex with someone who has the virus, even if they don’t have signs or symptoms.
An HPV infection increases the likelihood of developing certain cancers, including anal cancer, as the virus causes subtle tissue changes that lead to the growth of cancerous cells without necessarily causing outwardly visible anal warts or raised lesions.
The CDC urges all men and women 45 years or younger to discuss the risks and benefits of getting vaccinated with your doctor. Since the HPV vaccine was approved in 2006, cervical cancer incidence has decreased, preventing infection from nine different types of HPV.
Conversely, there has been an increase in cases of oral and anal cancer among men. The rise in HPV rates may be responsible for this increase.
Anal cancer originates in the tissues of the anus, which is the opening at the end of the gastrointestinal tract where bowel movements leave the body. It typically involves the growth of cancerous cells within the lining of the anus, often beginning as small, noncancerous (benign) growths.
Hemorrhoids, on the other hand, are swollen veins in the lowest part of the rectum and anus. They're similar to varicose veins inside the rectum (internal hemorrhoids) or around the anus (external hemorrhoids). Hemorrhoids are not cancerous and are often caused by pressure in the lower rectum due to straining during bowel movements, obesity, or pregnancy.
Because they share common symptoms like rectal bleeding and anal discomfort, it can be difficult to tell the difference between these two conditions. Specific characteristics of symptoms may make them more (or less) likely to be cancerous.
Bleeding: While both hemorrhoids and anal cancer can cause rectal bleeding, bleeding associated with hemorrhoids often occurs during bowel movements and is usually bright red. Anal cancer bleeding might be less related to bowel movements and more persistent overall.
Pain: Hemorrhoids typically cause discomfort and pain during bowel movements, which is relieved afterward. Anal cancer pain can be more constant and not necessarily related to bowel movements.
Lumps or swelling: Both conditions can cause lumps near the anus. Hemorrhoidal lumps are often soft and may be painful if thrombosed (filled with blood clots), whereas lumps from anal cancer tend to be firmer and not as painful initially.
Unexplained weight loss: Significant weight loss without any changes in diet or exercise routines is a more alarming symptom and is often associated with various types of cancer, including anal cancer.
Lymph node swelling: Enlargement of lymph nodes, particularly in the groin area, without a clear infection or other causes, can be a sign of cancer spreading.
Persistence and progression: Symptoms that persist over time or worsen, despite treatment or changes in lifestyle, could be more indicative of cancer. For instance, rectal bleeding or anal pain that doesn't improve or intensify should be taken more seriously.
Combination of symptoms: The presence of multiple symptoms simultaneously increases the likelihood of them being indicative of a more serious condition like cancer. For example, experiencing rectal bleeding combined with unexplained weight loss and changes in bowel habits is more concerning than any one of these symptoms alone.
Anal cancer symptoms are more concerning in older patients or those with multiple risk factors. Lifestyle choices, preventative healthcare, and awareness of risk factors are essential in reducing the chance of developing it.
Human papillomavirus (HPV): The rise in anal cancer rates is primarily attributed to the increased prevalence of HPV cases.
Smoking: This is a known risk factor for many cancers, including anal cancer.
Diet: Food choices play a significant role in maintaining overall health, including the gastrointestinal system's health and immune function.
Unprotected anal sex: Unprotected anal intercourse can increase the risk of anal cancer in men and women. This is because it can increase the risk of HPV infection.
Multiple sexual partners: Having multiple sex partners can increase the risk of anal cancer as it increases the risk of HIV or HPV infection.
Human immunodeficiency virus: Cancer research shows that HIV-infected people have a higher risk of anal cancer than the general population. People with advanced HIV disease, like AIDS, have an increased risk of early-stage and invasive HPV-associated cancers, including anal cancer. However, screening and early treatment can reduce the risk of anal cancer in HIV-positive individuals by 57%.
History of other cancers: Women with a history of cervical cancer, vaginal, or vulvar cancer have an increased risk of anal cancer, mainly due to their association with HPV infection.
While there is no official guidance for anal cancer screening, your doctor may perform a digital rectal exam and collect tissue samples with a swab or brush. The samples are part of a cancer screening test called an anal pap test. If results are abnormal, or there are other signs of anal cancer present, a physical examination with an anoscope can help your doctor see tissue changes or abnormalities.
Anal cancer diagnosis involves a tissue biopsy which is examined under a microscope for evidence of cancer cells. Advanced cases that have spread (metastasis) often appear in the lymph nodes.
Magnetic resonance imaging (MRI), a test that uses radio waves and strong magnets to create detailed pictures, may help oncologists determine if the cancer has spread and to what extent.
Anal cancer is a type of gastrointestinal cancer that has recently become more common. Early stages of anal cancer may present with subtle symptoms like changes in your bowel habits or rectal bleeding. Recognizing these symptoms and understanding risk factors, like HPV infection or a weakened immune system, are vital for early diagnosis and treatment.
Since HPV is a significant risk factor for anal cancer, getting vaccinated against HPV may help prevent cancer linked to the virus. Safer sex practices, like using condoms, can reduce the risk of HPV transmission, and limiting sexual partners can also decrease exposure to all sexually transmitted infections (STIs) that, by proxy, increase your risks.
Awareness of the symptoms of anal cancer and seeking timely health care can significantly impact outcomes. Take Ezra's five-minute quiz to get a personal risk assessment for all types of cancer. Understanding one's risk factors, including HPV infection and gastrointestinal health history, can guide discussions with your healthcare provider.