To better understand anal cancer, it is important to first understand the anatomy and function of the anus. The anus is the opening at the end of the rectum, through which feces are expelled from the body.
Anal cancer originates when the cells lining it begin to grow uncontrollably. This abnormal growth forms a tumor that can be benign (noncancerous) or malignant (cancerous). Anal cancer can invade surrounding tissues and, in advanced stages, spread to other parts of the body (metastasis). Most anal cancers are squamous cell carcinomas, which originate in the flat, thin cells that line the surface of the anus.
This cancer can significantly impact the patient’s quality of life, causing pain, bleeding, and difficulty defecating.
Symptoms of anal cancer
It is important to remember that the symptoms of anal cancer can vary considerably from person to person, and some people may not experience any symptoms in the early stages. In addition, many of these symptoms can be caused by other conditions, such as hemorrhoids, anal fissures, or infections. Therefore, if you experience any of these symptoms, it is essential to consult a doctor for an accurate diagnosis. The most common anal cancer symptoms include:
Early symptoms:
among the first symptoms are anal bleeding, which can be mild or heavy and is often mistaken for hemorrhoids; persistent anal itching; pain or discomfort in the anus, especially during bowel movements; a feeling of having a mass or lump in the anus; and changes in bowel habits, such as diarrhea or constipation.
Late symptoms:
as the disease progresses, symptoms may become more severe and include intense anal pain, foul-smelling anal discharge or pus, swollen lymph nodes in the groin or around the anus, and unexplained weight loss.
Classification of anal cancer
Classification of anal cancer is essential to determine the best course of treatment. In addition to TNM staging, which describes the extent of the tumor, it is important to classify the cancer according to the type of cell from which it originates. This provides valuable information about tumor behavior and helps guide treatment decisions. The most common anal cancer types include:
Squamous cell carcinoma: it is the most common type of anal cancer, representing approximately 85% of cases. It originates in the thin, flat cells that line the surface of the anus and the anal canal.
Adenocarcinoma: it originates in the glandular cells that produce mucus in the anus. It is less common than squamous cell carcinoma and accounts for about 10% of cases.
Basaloid carcinoma: it originates in the basal cells, which are found in the lower layer of the skin. It is less common than the other types and often behaves more aggressively.
Other uncommon types: these include anal melanoma, sarcoma, and lymphoma.
Causes of anal cancer
Understanding the causes of anal cancer is crucial for prevention and the development of treatment strategies. Human papillomavirus (HPV) infection is the leading cause of anal cancer, especially types 16 and 18. HPV is a common virus that is transmitted through sexual contact. s 16 y 18. El VPH es un virus común que se transmite por contacto sexual.
There are some factors that increase the risk of developing anal cancer. These risk factors do not guarantee that a person will develop anal cancer, but they increase the likelihood compared to the general population.
Human papillomavirus (HPV) infection: infection with certain types of HPV, especially HPV-16 and HPV-18, is the most important risk factor for anal cancer.
Risky sexual practices: sexual practices that increase the risk of contracting HPV, such as unprotected anal sex and having multiple sexual partners, also increase the risk of anal cancer.
Smoking: smoking cigarettes weakens the immune system and increases the likelihood of persistent HPV infection.
Weakened immune system: as is the case for people with the human immunodeficiency virus (HIV).
Complications of anal cancer
Anal cancer can cause various complications that affect the patient’s quality of life. These include:
Fecal incontinence: difficulty controlling bowel movements can be a complication of anal cancer or its treatment, affecting the patient’s quality of life.
Chronic pain: some people with anal cancer may experience persistent pain in the anal or rectal area, even after treatment.
Chronic constipation: anal cancer or its treatment can cause chronic constipation, which can be difficult to manage.
Lymphedema: the accumulation of lymphatic fluid in the tissues, known as lymphedema, can occur after surgery or radiation therapy for anal cancer, causing swelling in the legs or groin.
Sexual dysfunction: anal cancer and its treatments, especially surgery and radiotherapy, can affect sexual function.
If you experience any of these symptoms, it is advisable to seek medical attention.
Diagnosis of anal cancer
Diagnosing anal cancer requires a thorough evaluation by a specialized medical team, which generally includes gastroenterologists, colorectal surgeons, radiation oncologists, and medical oncologists. The diagnostic process involves a series of tests to confirm the presence of the tumor, determine its location, size, and characteristics, and rule out other conditions.
Physical examination: the doctor will perform a digital rectal exam to feel the anal and rectal area and detect any abnormalities, such as lumps, masses, or hardened areas. The doctor will also examine the lymph nodes in the groin for any signs of swelling or enlargement.
Anoscopy: it is a procedure that uses an anoscope, a thin instrument with a light, to visualize the inside of the anus and anal canal. It allows the doctor to examine the lining of the anus and rectum for any abnormalities, such as changes in the color, texture, or shape of the tissue.
Rectoscopy: similar to anoscopy, rectoscopy allows for the visualization of the rectum, the final part of the large intestine, to detect possible tumors or polyps.
Biopsy: if any abnormality is detected during the physical examination or anoscopy, a biopsy is performed. This procedure involves removing a small tissue sample from the suspicious area for laboratory analysis. A biopsy is the only way to confirm the diagnosis of anal cancer and determine the cell type and grade of the tumor. There are different types of biopsies, such as incisional biopsy, excisional biopsy, and needle biopsy.
Imaging tests: imaging tests, such as endorectal ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), can be used to assess the extent of the cancer and determine whether it has spread to the lymph nodes or other organs. Endorectal ultrasound uses sound waves to create images of the anus and rectum, while CT and MRI use X-rays and magnetic fields, respectively. Another alternative is positron emission tomography combined with CT (PET/CT), an advanced imaging technique that can be used to detect the presence of metastases in other parts of the body. These tests help stage the cancer and plan treatment.
Anal cancer treatment
The treatment of anal cancer generally involves a multidisciplinary approach, tailored to the individual needs of each patient. The medical team, which includes colorectal surgeons, radiation oncologists, medical oncologists, and other specialists, will work together to develop a personalized treatment plan. Treatment options include:
Radiotherapy: it is a fundamental pillar in the treatment of anal cancer. It uses high-energy radiation to destroy cancer cells and reduce the size of the tumor. It is administered externally, using a linear accelerator. At HM Hospitales, we offer advanced radiotherapy, including intensity-modulated radiotherapy (IMRT) and image-guided radiotherapy (IGRT), for greater precision and fewer side effects.
Chemotherapy: it uses medications to eliminate cancer cells. It can be administered intravenously, orally, or topically, depending on the type of medication and the stage of the cancer. Chemotherapy is often combined with radiotherapy for more effective treatment, especially in locally advanced stages.
Surgery: surgery is reserved for specific cases such as tumors that do not respond to other treatments or recurrences. Surgical options include local resection, for small, localized tumors in early stages, where the tumor and a small amount of surrounding healthy tissue are removed; abdominoperineal amputation, a more extensive procedure that involves the removal of the anus, rectum, and part of the sigmoid colon, creating a permanent colostomy, which is performed for large, recurrent tumors or tumors that have invaded the anal sphincter muscles; Mohs microsurgery, a specialized technique for removing skin cancer, including anal melanoma, which involves removing the tumor in thin layers and microscopic examination of each layer to ensure complete removal of cancer cells; wide local excision, similar to local resection but with a wider margin of healthy tissue removed, for larger tumors or those with poorly defined margins; cryosurgery, which uses liquid nitrogen to freeze and destroy cancer cells in small, superficial tumors. The choice of surgical procedure depends on the size, location, and extent of the tumor, as well as the patient’s overall health.
Combined therapy: it generally includes radiotherapy and chemotherapy, with or without surgery. It is the most common treatment for anal cancer. This multidisciplinary approach offers the best cure rates and preservation of anal function.
Targeted therapy: it uses drugs that target specific characteristics of cancer cells, such as genetic mutations or specific proteins. Different types of targeted therapy for anal cancer are being researched.
Immunotherapy: it is a type of treatment that helps the body’s immune system fight cancer. Different types of immunotherapy are being researched for anal cancer, including immune checkpoint inhibitors, which block proteins that prevent the immune system from attacking cancer cells.
Remember that this article is for informational purposes only and does not replace professional medical advice. If you suspect you have anal cancer, consult a specialist to obtain an accurate diagnosis and a treatment plan tailored to your needs. stico preciso y un plan de tratamiento adecuado a tus necesidades.
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