What is Anal Cancer?
Anal cancer is an uncommon type of cancer. In 2017, it was estimated that around 8,200 people in the United States were diagnosed with anal cancer, and approximately 1,100 people died from it.
What Causes Anal Cancer?
Studies have found a strong connection between human papillomavirus (HPV), particularly HPV 16, and the development of anal cancer. This means that it occurs more often in certain groups, like young men who have viral infections related to the genitals. A comprehensive research study revealed a link between the amount of sexual activity, sexually transmitted infections, and anal cancer.
Earlier, smaller studies suggested that anal sex could raise the risk of anal cancer, but this hasn’t been proven in a larger research study. Apart from HPV, infections caused by genital warts, also known as condylomata, have been connected to anal cancer in both the general population and in gay men.
Further research showed that in women who had genital warts, anal cancer was often associated with HPV and another sexually transmitted infection, Chlamydia trachomatis. Interestingly, in men who didn’t have a history of genital warts, anal cancer was linked more often to gonorrhea infection.
Beyond these reasons, there appears to be a connection between acquired immunodeficiency syndrome (AIDS) and anal cancer. In fact, patients infected with the human immunodeficiency virus (HIV) – the virus that causes AIDS – have a risk of developing anal cancer that is 40 times higher compared to the general population.
Risk Factors and Frequency for Anal Cancer
Anal cancer, while rare, is still a concern as it contributes to 2.5% of all intestinal cancers in the United States. Figures from the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program (SEER) recorded 8200 new instances in 2017, alongside 1100 estimated deaths. Survival rates from 2007 to 2013 stood at 66.9% within a period of five years.
Accumulated statistics from 2012 through 2014 indicate that roughly 0.2% of both men and women are diagnosed with anal cancer during their lifetime. The occurrence rate of anal cancer tends to be higher in men than in women, with a ratio of approximately 2 to 3.5. The possibility of contracting anal cancer increases in individuals with certain underlying conditions or habits.
- Anal cancer is seen more frequently in people with viral infections of the genitals, like HPV and HIV.
- Higher incidence rates are found in those with multiple sexual partners.
- Individuals engaging in anal-receptive sexual activities are at a heightened risk.
- Those with condyloma infections or AIDS also report higher rates of anal cancer.
Signs and Symptoms of Anal Cancer
A complete examination and understanding of the patient’s history is crucial for patients suspected of having anal cancer. Some patients may experience no symptoms, while others could have a variety of symptoms that include:
- Bleeding from the anus
- Pain in the anus or pelvic region
- Weight loss
- Feeling a lump in the anus or rectum
- Anal irritation
- Prolapsed tissue
- Incontinence (loss of control over bowel movements)
- Severe constipation
Unfortunately, because of the stigma associated with anal cancer, many patients delay seeking medical help. Roughly 19% of patients wait six months or more after symptoms start before they see a doctor. Misdiagnosis also occurs with anal cancer, with some cases mistakenly identified as hemorrhoids. This happens in about 27% of cases. Therefore, a complete history, including medical history, sexual activity history, and any history of sexually transmitted diseases, is crucial. Similarly, a complete physical examination is important and should include checking the rectum with a finger (digital rectal examination), checking for swollen lymph nodes in the groin (inguinal lymph node palpation), and performing a gynecologic examination on female patients, including tests for cervical cancer.
Testing for Anal Cancer
When you go in for your doctor’s visit, they will start by asking you about your medical history and performing a physical examination to trace your symptoms. They will need to conduct laboratory and radiology tests for further clarification.
The laboratory tests could include a complete blood count, which gives the doctor a general idea about your overall health. They might also take a chemistry panel, which can offer information about your liver and kidney function, blood sugar levels, and electrolyte balance. In specific cases, tests for HIV might be needed.
Anal exams (anoscopy) , anal mass biopsy, or fine-needle aspiration might also be necessary. These tests involve the use of thin needle or tool to collect a small sample of tissue or fluid from the anal area to examine under a microscope `for issues.
Imaging tests like CT scans, PET scans, or MRIs might be required. These provide detailed pictures of inside your body, allowing the doctor to check if the disease has spread to other parts. Imaging tests are especially necessary when the disease might have spread (called metastatic disease). If anal cancer is confirmed, there will be additional testing for HPV, gonorrhea, and chlamydia, as these conditions are often associated with anal cancer.
Treatment Options for Anal Cancer
In the past, the main treatment for anal cancer was a particular type of surgery that was successful in about half of the cases, but often resulted in significant health issues. Nowadays, localized anal cancer–meaning it hasn’t spread–is usually treated with a combination of chemotherapy and radiation.
Like with many other types of cancer, the specifics of the treatment depend on how advanced the disease is when discovered. For instance, small tumors without spreading to the lymph nodes are usually treated with a local surgical removal. If the removed tissue has clear margins–meaning there’s no cancer at the edges of the tissue sample–doctors usually just monitor the patient.
However, if the small tumors are more complex, or if the cancer is more advanced but hasn’t spread to other parts of the body, the usual treatment consists of chemotherapy and radiation. A common regimen for this involves a specific combination of two chemotherapy drugs with radiation. This approach has demonstrated to reduce the risk of local recurrence by 46%, with a complete response rate–meaning no detectable cancer–in 70% to 80% of cases and a five-year survival rate of over 65%.
There’s been research into alternative drug combinations, but a large study involving 682 patients found that the established regimen is still the most effective. The only situation in which an alternative regimen might be used is if a patient isn’t able to receive the usual treatment for some reason. If the cancer has spread to the lymph nodes, added radiation therapy or lymph node surgery may be needed, although the latter is rarely done.
After treatment, there is a detailed follow-up protocol. Doctors keep a close eye on patients to see how effective the treatment was and to detect any possible recurrence. Doctors do a physical examination about two to three months after treatment, including an examination of the anal area and the lymph nodes in the groin. Patients with no signs of disease after treatment are closely monitored with regular examinations and scans for up to five years.
If the cancer seems to be persisting three months post-treatment, doctors continue to monitor patients for up to six months, as long as the cancer doesn’t seem to be getting worse. This is because some anal cancers can take a long time to respond to treatment. Any signs of disease progression should prompt further investigation and possible additional treatment.
For patients diagnosed with metastatic disease, which means the cancer has spread to other parts of the body, treatment is usually palliative – focused on relieving symptoms and improving quality of life. Treatments used for these patients can include a combination of different chemotherapy drugs. There’s also ongoing research into the role of immunotherapy–therapy that boosts the body’s immune system–in treating this type of cancer.
What else can Anal Cancer be?
Possible conditions that could cause anal or genital discomfort can include:
- Chancroid (a type of sexually transmitted infection)
- Anal fissure or fistula (tears or abnormal connections in the anal tissue)
- Hemorrhoids (swollen veins in the lower part of the rectum and anus)
- Condylomata acuminatum (genital warts)
- Psoriasis (a skin condition causing red, flaky, crusty patches of skin)
Possible Complications When Diagnosed with Anal Cancer
Complications from treating this condition mainly include:
- Side effects from radiation treatment
- Negative reactions to chemotherapy
- Reduced sexual desire
- Problems with bowel functions
- Inflammation of the rectum, also known as proctitis
- Bleeding from the rectum
- Complications from surgery like narrow passages, abnormal connections between organs or vessels, and infections at the surgical site
