In the last issue of Positively Aware, I wrote about the need to be proactive about your anal health by getting your annual digital anorectal exam (DARE) and your anal pap smear. Your doctor may tell you that your DARE was not normal and a more thorough exam needs to be undertaken. Another scenario you may encounter is that your DARE was normal, but you get a phone call a week later telling you the anal pap smear was not. What do you do now? Read on for the second part of “Getting to the Bottom of It”.
An abnormal digital anorectal exam may reveal shallow ulcerations, anal pain or tenderness, raised or rough surface areas, thickened tissue, warts, or other abnormalities. Perhaps you’ve told your doctor you are experiencing one or more of the following symptoms: rectal bleeding, anal itching, pain or discomfort in the anal area, anal irritation, change in stool diameter, pain or difficulty with a bowel movement or with receptive anal sex, abnormal anal discharge, swollen groin lymph nodes, or other anal symptoms.
What about the anal Pap smear? A swab is inserted about 2 inches into your rectum and cells are collected by rotating the swab as the swab is removed. The cells on the slide are stained and then interpreted by a pathologist. If the Pap smear was normal, there was no evidence of HPV-related changes and no additional evaluation is indicated at that time. It is still possible to have high-grade dysplasia (abnormal cells) because the swab may not have gotten into all of the anal folds and come into contact with an area of high-grade dysplasia. If you were told the Pap smear was abnormal, it means that the sample of cells from the anus may have HPV changes that make the cells appear atypical or low-grade to high-grade dysplasia. High-grade dysplasia is considered precancerous.
You may hear the following terminology in the description of the results: Negative or Normal, ASC-US (atypical squamous cell-undetermined significance), ASC-H (atypical squamous cells-cannot exclude HSIL or high-grade dysplasia), LSIL (low-grade squamous intraepithelial lesion or low-grade dysplasia), HSIL (high-grade squamous intraepithelial lesion or high-grade dysplasia), HSIL with features suggestive of invasion, or Squamous cell cancer (invasive anal cancer). Any result other than Negative or Normal needs to have a more thorough examination to determine the exact nature of the abnormal result.
The most thorough exam of the anus and anal canal is the High Resolution Anoscopy (HRA). The group at the UCSF Anal Dysplasia Clinic at the University of California San Francisco developed and pioneered the HRA technique in the early 1990’s. The technique was adapted from the colposcopy, which was first developed in the 1930s in Germany to examine the cervix for cancer and precancerous lesions. The HRA utilizes a microscope known as the colposcope. The microscope is essential in magnifying the anal mucosa to help identify abnormal areas. HRA can be performed comfortably in the physician’s office. Some providers perform HRA in the operating room or surgery center, which is usually not warranted due to the cost and inconvenience.
Most anal dysplasia specialists perform the HRA with the patient lying on their left side with the buttocks at the end of the exam table and the feet resting on one stirrup. Some providers may have you bend over the end of a special exam table and kneel on a pad while the HRA is performed. When you are in position, the provider carefully exams the exterior tissue around the anus looking for any abnormalities such as ulcerations, discolored areas of skin, or warts. The provider uses an anesthetic gel to perform the digital anorectal exam. The provider feels the surface of the intra-anal tissue for any abnormalities, which can help the provider evaluate the area when he visually examines it with the microscope.
After the DARE, a small, lubricated, disposable anoscope is inserted into the anus a few inches. A wooden cotton swab that is thinly wrapped with gauze soaked in acetic acid (vinegar) is inserted through the anoscope and left in the anus. After one to two minutes, the swab is removed and the anoscope is reinserted. The microscope is positioned and the entire anal canal and anus is examined under magnification with a very bright focused light. More vinegar is applied with a cotton swab to look for abnormal lesions. It is also important to use Lugol’s solution (iodine) to further evaluate for any abnormal lesions.
The area of particular interest that is examined is known as the squamocolumnar junction or transformation zone. The squamocolumnar junction is the area where the outside squamous skin cells transition to the inside columnar cells of the rectum. The anoscope is manipulated to visualize the entire circumference of the squamocolumnar junction, which is where the majority of HPV-related lesions are found. HPV infects squamous cells and does not go up higher into the rectum’s columnar cells.
Vinegar turns HPV-related lesions acetowhite and they appear as dense, opaque areas or lesions. These lesions are evaluated for their surface characteristics such as texture, thickening, or ulceration. Lesions are next evaluated for abnormal blood vessels, which may be characteristic of high-grade or precancerous lesions. Lugol’s solution is applied to the squamocolumnar junction to also help differentiate abnormal lesions. Lugol’s solution turns high-grade lesions a yellow-mustard color where as normal tissue stains a mahogany brown.
Once a lesion is found, a biopsy is obtained using forceps. The tissue is then placed in a bottle with formalin and sent to the pathologist for examination. Biopsies taken during HRA are usually very small. The biopsy removes the surface and underlying tissue including the basement membrane so the pathologist can determine the level of severity of the dysplasia and whether or not there is invasion or cancer is present.
After the intra-anal area is thoroughly examined with the microscope and biopsies are obtained, the anoscope is removed. A vinegar-soaked piece of gauze is then placed on the skin at the anal opening and left there for a minute. The anus and perianal skin is then examined with the microscope. Any abnormal looking areas are biopsied. HPV-related lesions are less common here but still may occur.
Treatment is based on the results of the biopsies. Low-grade dysplasia is a category of HPV disease that includes both warts and mild dysplasia. Low-grade dysplasia does not need to be treated and these lesions are considered benign. In many cases, this type of dysplasia does not cause any problems and usually does not progress to high-grade dysplasia or precancerous lesions. Most patients and providers prefer to treat warts. Warts can cause bleeding or discomfort. They can also be embarrassing and psychologically distressing. Large bulky warts or tissue near warts may have areas of high-grade dysplasia which may be difficult to see because of the size of the warts. Intra-anal wart treatment is based on patient preference and the extent of the disease.
High-grade dysplasia or precancerous lesions have the potential in some individuals to progress to cancer. Most anal dysplasia specialists recommend treatment of high-grade dysplasia because we do not have a way to distinguish which lesions progress to cancer and which ones do not. Like warts, the goal of treatment is to get rid of the precancerous lesions. Although lesions can recur, any lesion that is successfully destroyed will be gone and cannot progress to a cancer.
There are several different types of treatment options depending on the severity of the dysplasia, the location of the lesions, and the extent of disease. Lesions can be treated surgically or with office-based therapies. Some treatments are applied by you and stimulate your immune system to kill HPV and decrease the amount of HPV that is in your body. These treatments are used off label at this time and are undergoing further study for efficacy. The most common treatments actually destroy the abnormal lesions with Infrared Cautery (IRC), electrocautery or laser. Some studies have shown these treatments to be successful in destroying these precancerous lesions.
There are circumstances in which high-grade dysplasia cannot be treated. Sometimes the amount of disease is so extensive that it would require destruction of the entire anal canal. Sometimes the patient is not physically able to handle an extensive procedure. Some patients may have continued recurrence despite treatments. It may be better in these patients to carefully monitor them for progression to cancer with HRA every 3-4 months.
Anal cancer is increasing in certain high-risk groups. Thorough examination of the anus, anal canal, and perianal skin with high resolution anoscopy is recommended for individuals with abnormal anal pap smears or with abnormal anal symptoms. Being aware of the risk of anal cancer and evaluating symptoms and treating precancerous lesions may prevent the development of cancer in high-risk individuals. At a minimum, increased awareness and evaluation can find early anal cancers when they are easier to treat.