Anal and Rectal Lesions - Anal Cancer

Question 1

What is anal carcinoma?

Answer 1

Malignancy lying exclusively in the anal canal - the borders : anorectal junction and anal margin (area of pigmented skin surrounding the anal orifice).

Question 2

Types of anal cancers (2).

Answer 2

1. 80% - SCC.

2. Other : Melanoma, Lymphoma, Adenocarcinoma.

Question 3

Spread of anal cancers (2).

Answer 3

1. Anal margin tumours spread to the inguinal lymph nodes.

2. More proximal tumours spread to the pelvic lymph nodes.

Question 4

Epidemiology of anal cancers (3).

Answer 4

1. Rare but incidence is rising in MSMs (due to widespread infection by HPV).
2. 2x commoner in females.
3. Mean Age at presentation : 85-89 with lymph node involvement.

Question 5

Risk Factors of anal cancers (4C).

Answer 5

1. HPV Infection (80-85% of SSCs) - HPV16/HPV18.
   1A. Anal Intercourse.
   1B. High lifetime number of sexual partners.
   1C. MSMs.
2. HIV or Immunosuppressive Medications.
3. Cervical Cancer History / CIN.
4. Smoking.

Question 6

Clinical Features of anal cancers (4).

Answer 6

1. Perianal pain and bleeding.
2. Palpable lesion.
3. Faecal incontinence.
4. Neglected tumour in female : rectovaginal fistula.

Question 7

Investigations of anal cancers.

Answer 7

1. Imaging : CT, MRI, Endo-Anal US, PET.
2. Staging : T - DRE, Anoscopic Biopsy and Inguinal Node Palpation.
3. Relevant Infection Screening.