Anal Cancer

Anal cancer can involve the skin around the anus and/or inside the anus (anal canal). They are abnormal cells that multiply and spread directly to contiguous area, or remotely to other organs through the lymphatics. Risk factors for anal cancer include untreated HPV infection (anal warts and dysplasia), high risk sexual behavior (anal sex, multiple sex partners), smoking, older age (55 and older), compromised immune system due to HIV or medication, history of cervical (HPV-related) cancer, history of radiation treatment for cancer of pelvic region such as prostate, bladder, cervical or rectal cancer and chronic inflammation in the anal area.

Symptoms of anal cancer

Early cancer may not cause any symptom. If tumor is external, you may notice a growth that increase in size over time. When growth continues, you may experience symptoms such as pain, bleeding, mucus or discharge. Cancer inside the anus may narrow and block the anal canal causing bleeding and difficulty with stool passage and change in your bowel pattern. When cancer invades the anal sphincter (the muscle you use to control your bowel), you may develop fecal incontinence. More advanced cancer that has spread outside of the anal area may cause swollen lymph nodes in the groin area, weight loss, general weakness. Occasionally anal cancer may present like anal fissure or fistula or may have symptoms similar to hemorrhoids.

Diagnosis and treatment of anal cancer

Anal cancer can be diagnosed by its appearance during exam in the office and is confirmed with biopsy, which is needed to determine the exact cell type of the cancer. While Dr. Choi can perform the exam and biopsy in her office, a more thorough exam under anesthesia is sometimes needed for accurate diagnosis and to determine the stage of the cancer, along with other imaging studies such as CT scan, MRI or ultaround. A colonoscopy is also needed to exclude other tumors in the large intestine. Anal cancer is staged by its size and whether it has spread to nearby lymph nodes or other organs, and the treatment depends on the cancer stage and location.

Most anal cancers are of squamous-cell type and are treated definitively with a combination of chemotherapy and radiation therapy, which can cure up to 80-90% of early stage anal cancer. Surgery is needed for a cure if the cancer does not regress after chemo and radiation therapy, if the cancer recurs after sometime, or for certain uncommon type of anal cancer. Surgery involves removing the rectum and anus and patient will have a permanent colostomy (the end of the colon is brought out to the skin on abdominal wall and a detachable bag is used to collect fecal waste). In cases where the cancer is very small and superficial and can be completely removed safely without compromising the anal function, it may be cured by surgically excising the tumor with a rim of normal tissue around it, without need for chemoradiation therapy. While chemo and radiation is given by the oncologists, regular follow-up exam by colorectal surgeon is important to determine if cancer is adequately treated, if additional therapy is needed, or to monitor for cancer recurrence.

Helpful links:


*American Society for Colon and Rectal Surgeons