Digital Ano Rectal Examination (D.A.R.E.)
Who might benefit from DAREs?
The purpose of performing a DARE is to diagnose anal cancers at an early stage (ideally <1cm diameter), when currently available treatments are usually highly effective. It should therefore be offered to anyone who either has been identified as being at high risk of anal cancer, or who is under investigation for unexplained anal symptoms. This includes:
- HIV positive homosexual men
- Anyone with a history of established anal high grade anal neoplasia or anal cancer
- HIV positive women
- Women with a history of genital HPV related conditions – such as CIN, cervical cancer and genital warts
- Immunosuppressed individuals – such as transplant recipients
- HIV positive heterosexual men
- Those with other conditions associated with immune dysfunction, such as systemic lupus
Note that anal cancers can be missed at anoscopy, as they may be submucosal and not visible on the surface.
Who might perform DAREs?
- Any healthcare worker looking after people with the above risk factors
- With training, and reasonable physical flexibility, it is possible to perform a DARE on oneself
The frequency of performing DAREs has yet to be established. However, those at highest risk of anal cancer (HIV positive homosexual men and those with a history of high grade anal lesions/cancer) should be offered annual DAREs.
The DARE Technique
A DARE is essentially a modification of the rectal examination performed on men as part of assessment of the prostate. Like any procedure, it is necessary to perform multiple examinations before becoming confident with the procedure. It includes the following steps:
- Explain why the procedure is necessary and what it will involve
- Always obtain explicit consent from the patient before undertaking a DARE
- Place the patient in the preferred position (typically left lateral)
- Perform a careful inspection of the perianal area, and note any abnormalities. A systematic approach, deliberately inspecting each quadrant in a clockwise fashion is recommended
- Ask the patient to breathe gently, but deeply
- Moisten a gloved index finger with lubricant (often supplemented with lignocaine)
- Place the lubricated finger on the anal margin and leave there for a few seconds, to allow the patient to adapt to the sensation
- Apply gentle, sustained pressure to the anus with the finger
- The external sphincter will relax within a few seconds
- Once the sphincter is relaxed, gently insert the finger until the free space of the rectum is felt. This typically requires insertion to the proximal interphalangeal joint, although the canal tends to be shorter in women
- Note that the anal canal is usually empty, unless the person has an urge to defaecate
- The posterior wall of anal canal is typically first palpated
- The finger is swept lengthwise down the anal canal, from proximal (internal) to distal (external), ensuring each quadrant is examined thoroughly
- The examining person will then need to change their position, to ensure that all quadrants are checked thoroughly
- The DARE typically finishes by palpation of the anterior wall of anal canal (noting the contour & size of prostate in males)
- If there is any doubt about the findings, the process should be repeated
If done thoroughly, a DARE should take about a minute to perform.
Cancers feel like hard, irregular lumps, sometimes tender, or with ulceration. There may be blood noticed on the finger.
Cancers can sometimes be deep within the anal lining (and potentially missed at anoscopy), or they may be above the surface.
If something is felt that does not disappear with pressure, or is painful, then proceed to anoscopy, or referral for a more expert opinion.
False positive findings can be caused by:
- Intra-anal warts – these are typically mobile and highly irregular
- Haemorrhoids – are usually compressible (unless thrombosed)
- Normal intra-anal papillae – are typically smaller and more mobile
- Scarring from previous surgery
False negative findings are a greater concern:
- Always seek expert assessment if unexplained symptoms persist
- If you are not confident that the examination has been performed adequately, always seek a second opinion
After a DARE
- Once the DARE has been completed in a satisfactory fashion, the finger is gently removed from the anus. There may be a small amount of bleeding from the rectum afterwards, particularly if haemorrhoids are present
- Clean any gel or blood from the perianal area after completing the examination
- Always discuss the findings from the DARE with the patient
A video of how to perform a DARE can be found at: