ANORECTAL CANCER – ANORECTAL CANCER – Symptoms and SignsSymptoms and Signs

Louise Fischer Med IVLouise Fischer Med IV

But first, some basic anatomy

Anorectal cancer – what the?

Anorectal cancer:a) Anal cancer

i) Anal canal cancerii) Anal margin cancer

b) Rectal cancer

Definitions according to WHO and AJCC (American Joint Committee on Cancer)

Anal canal extends from upper border to the lower border of the internal and external sphincter (ie. from the pelvic floor to the anal verge).

Anal margin tumours occur outside the anal verge but within a 5-6cm radius to the anus.

Anal canal cancer 1.5% of GI malignancies, estimated 3400 new cases/yr. Risk Factors include:

female gender chronic anal irritation (more specifically chronic infection

with HPV) anoreceptive intercourse HIV positive anogenital warts history of STDs increased number of sexual partners history of cervical/vulvar/vaginal cancer (personal or

partner) Immunosuppression LT use of corticosteroids cigarette smoking.

Anal Canal Cancer (cont) Tumours of anal canal tend to be aggressive,

nonkeratinizing, and associated with HPV infection.

Epidermoid (Squamous, Basoloid, Mucoepidermoid) Carcinoma

Symptoms Prior to diagnosis, there is generally a long history of minor perianal complaints such as bleeding / itching / perianal discomfort / palpable anal mass.

Signs At presentation, disease may be extensive with approx ½ of lesions extending beyond the bowel wall / perianal skin. Inguinal nodal metastases are found initially in 15-20% of patients and develop in 10-15% over time.

Anal Margin Cancer

Men have a 4-fold increased risk of anal margin carcinoma.

Tumours of anal margin generally well differentiated, keratinizing tumours that behave similarly to other squamous cell carcinomas of the skin and are treated accordingly.

Anal Margin Cancer (cont)Squamous Cell Carcinoma

Basal cell carcinoma

Bowen’s Disease

Paget’s Disease

Symptoms

Mass / bleeding / pain / discharge / itching / tenesmus

Bleeding / itching / pain

Perianal burning / itching /pain

Characteristically severe intractable pruritus.

Signs Large, centrally ulcerated lesions with rolled everted edges. Feels hard and woody on palpation.

Lesions appear with raised, irregular edges and central ulceration.

When grossly apparent, lesions appear scaly, discrete, erythematous, and sometimes pigmented.

On physical examination, an erythematous, eczematoid rash is apparent.

Rectal Cancer Incidence Approx 135 00 new cases of colorectal cancer

(CRC) occur in the US each year, 2/3 of these cases occur in the colon ad 1/3 in the rectum.

Prevalence the lifetime risk of developing colorectal malignancy is approx 5.9% in the general population (in the US).

Race Western countries tend to have a higher incidence than Asian and African countries. Among religious denominations, CRC occurs more frequently in the Jewish population.

Sex Incidence of colorectal malignancy is slightly higher in males than females.

Age Incidence peaks in 70’s (some cases reported in young children).

Rectal cancer (cont) Etiology unknown but appears

to be multifactorial in origin Diet:

High meat and animal fat diet associated with CRC

High fibre diet protective against CRC Increased dietary intake of calcium

protective effect Daily alcohol-drinkers 2-fold ↑risk

Beer consumption >15L/mth ↑risk in men.

Rectal cancer (cont)

Rectal cancer (cont)

Lifetime risk of CRC in 1st-degree relatives of a patient with CRC

Population risk 1 in 50

1x 1st-degree relative affected (any age)

1 in 17

1x 1st-degree relative + 1x 2nd-degree relative affected

1 in 12

1x 1st-degree relative affected (age<45)

1 in 10

2x 1st-degree relatives affected 1 in 6

Autosomal dominant pedigree 1 in 2

Rectal cancer (cont) Genetic disorders

Familial adenomatous polyposis (FAP) Autosomal dominant inherited syndrome that results

in the development of more than 100 adenomatous polyps and a variety of extraintestinal manifestations.

The defect is in the APC gene, which is located on chromosome 5 at locus q21.

The disease process causes the formation of hundreds of intestinal polyps, osteomas of the bone, desmoid tumours, and, occasionally, brain tumours.

The increased number of polyps predisposes patients to a greater risk of cancer. If left untreated, colorectal cancer develops in nearly 100% of these patients by age 40years.

While the hereditary link is documented, approx 20% of FAP cases are caused by spontaneous mutation.

Rectal cancer (cont) Hereditary nonpolyposis colorectal cancer (HNPCC)

Autosomal dominant inherited syndrome that occurs because of defective mismatch repair genes located on chromosomes 2, 3, and 7.

Patients have the same number of polyps as the general population, but their polyps are more likely to become malignant. These patients also have a higher incidence of endometrial, gastric, thyroid, and brain cancers.

Amsterdam Criteria for HNPCC: 3+ cases of CRC in minimum of 2 generations 1 affected individual must be a 1st-degree relative

of the other 2+ cases 1 case must be diagnosed at age <50 CRC can be replaced by endometrial or small

bowel cancer. FAP should be excluded

Rectal cancer (cont) Inflammatory Bowel Disease

Ulcerative colitis The incidence of malignancy increases with duration.

After 10yrs, the incidence of CRC in ulcerative colitis is approximately 1% per year.

Crohn’s disease The incidence of CRC in patients with CD is 4-20 times

greater than that of the general population. Cancer occurs in patients with disease of at least 10years’ duration. The average age at diagnosis (ie. 46-55) is younger than that of the general population.

Cancers often develop in areas of strictures and in defunctionalized segments of intestine. In patients with perianal Crohn’s Disease, malignancy often present in fistulous tracts.

Patients with Crohn colitis undergo the same surveillance regimen as those with UC.

Rectal cancer - symptoms

It is very important to take a compete history from the patient, including a family history and assessment of Risk Factors for developing rectal cancer.

Many rectal cancers produce no symptoms and are discovered during digital / proctoscopic screening examinations.

Rectal cancer - symptoms

Bleeding 60%

Change in bowel habits 43%

Occult bleeding 26%

Abdominal pain 20%

Other: Malaise 9%

Bowel obstruction 9%

Pelvic pain 5%

Peritonitis from perforation

3%

Liver metastasis 1%

Rectal cancer - symptoms

Bleeding Often attributed to other causes (eg

haemorrhoids), especially if the patient has a history.

Profuse bleeding and anaemia are rare.

May be accompanied by the passage of mucus and warrant further investigation.

Rectal cancer - symptoms Change in bowel habit

Often occurs in form of diarrhoea, particularly if the tumour has a large villous component.

Some patients experience a change in caliber of the stool.

Large tumours can cause obstructive symptoms.

Tumours located low in the rectum can cause a feeling of incomplete evacuation and tenesmus.

Rectal cancer - symptoms Abdominal pain

Partial large bowel obstruction may cause colicky abdominal pain and bloating.

Back pain usually is a late sign caused by a tumour invading / compressing nerve trunks.

Urinary symptoms may occur if the tumour is invading or compressing the bladder / prostate.

Rectal cancer - signs Physical examination is performed with specific

attention to possible metastatic lesions, including enlarged lymph nodes or hepatomegaly.

Digital Rectal Examination The average finger can reach approx 8cm above the

dentate line. Tumours can be assessed for size, ulceration, and presence

of any pararectal lymph nodes. Fixation of the tumour to surrounding structures (eg sphincters, prostate, vagina) also can be assessed.

DRE also permits cursory evaluation of he patients’ sphincter function. This information is necessary when determining whether a patient is a candidate for a sphincter-sparing procedure.

List of resources Burkett HG, Quick CRG, Deakin PJ. Essential Surgery:

Problems, Diagnosis and Management. 3rd ed. Churchill Livingstone. 2004.

Cirincione E, Cagir B. “Rectal cancer.” eMedicine. Retrieved 23 April 2005 http://www.emdedcine.com/med/topic1994.htm.

Friedman SL, Mcquaid KR, Grendall JH. “Anorectal Diseases.” Current Diagnosis & Treatment in Gastroenterology. 2nd ed. McGraw-Hill. 2003. p452-479.

Kumar P, Clark M. Clinical Medicine. 5th ed. WB Saunders. 2002

Yamada T, Alpers DH, Kaplowitz N, et al. “Anorectal Diseases.” Textbook of Gastroenterology. 4th ed. Lippincott Williams & Wilkins. 2003. p1990-1991