ANAL CANCER, ANAL DYSPLASIA AND ANAL CONDYLOMA
The incidence of anal squamous cell cancer (SCC)
has increased 2.7 times in men and 1.7 times in women from 1973 to 2000.
The current incidence in men and women is 1.6 and 1.5 per 100,000. This
translates to 4-5 anal SCC cancers per year in the Westsound area. The
greatest risk factor for anal SCC is infection with the human papilloma
virus (HPV). HPV is a robust virus that can survive up to 6 hours outside
the body and enter through any break in the skin or mucosa. Direct anal
intercourse is not needed for anal warts to develop. Over 100 serotypes of
HPV have been identified, though types 6 and 11 are the most common in
anal warts. Serotypes 16 and 18 are associated with SCC in both the anal
area and the cervix. Virus particles attach to native DNA and readily
escape any host immune response. In 1997 over 24 million Americans were
infected with HPV. While most anal warts are from non-oncogenic strains
genital and anal lesions from oncogenic and non-oncogenic strains are
identical to inspection and microscopic evaluation. HIV positive patients
have a much higher rate of carcinoma in situ or anal intraepithelial
neoplasm III (AIN III), reaching 30% in some series.
Cervical intraepithelial neoplasm is also linked to HPV and the
progression from CIN III to invasive carcinoma is clearly documented.
Unfortunately, there has not been a clear like of AIN III to anal
carcinoma. This has lead to controversies in management. Some advocate
frequent anal Pap smear and anal colposcopy but this has not been shown to
decrease the rate of anal cancer. In fact, anal Pap smear is much less
reliable than cervical Pap smear. Cervical pap is obtained from the
cervical transition zone under direct vision and yields 8,000 to 12,000
cells and 83-89% accuracy rate. In contrast, anal Pap smear is obtained
blindly and yields only 200-300 cells. This achieves a 31-84% false
negative rate and a 40-50% false positive rate. In contrast direct biopsy
of visible lesions documents dysplasia in over 90% of cases.
Treatment of anal condyloma and AIN III is problematic due to a high
recurrence rate. Treatment of all visible lesions with excision, laser
ablation of electrodessication all result in over a 30% recurrence rate
for condyloma. Treatment with imiquimod (Aldara) for 6 weeks prior to
surgical intervention has a lower recurrence rate, but the pain of
treatment interferes with compliance. At surgery excisional biopsy of the
largest lesions allows histologic confirmation of dysplasia, if |
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present. Frequent re-inspections and
re-treatments are needed for successful irradication. AIN III lesions
should have re-inspection every 3 months.
If invasive SCC is found, these are
excised with negative margins at the anal margin or perineum. Anal canal
lesions achieve excellent results with primary chemoradiation, preserving
radical surgery for residual cancer or recurrence after chemoradiation.
NORTH COUNTY CLINIC
Starting Thursday January 12th Dr. Green will
see patients in clinic on alternate Thursdays in the Poulsbo offices of
Dr. Michael Jungkeit. Appointments can be made through the Bremerton
office at 360-377-4717.
PELVIC FLOOR FORUM
The Kitsap Pelvic Floor Forum scheduled for Thursday March 9th has been
cancelled. Future Pelvic Floor Forum topics and meetings will be announced
in upcoming KCRS Messengers.
MARCH IS: COLORECTAL CANCER AWARENESS MONTH
Current recommendations are colonoscopy every 10 years starting at 50 for
average risk patients. Patients with a family history of colorectal
cancer, previous polyps or inflammatory bowel disease should have
colonoscopy more often. If the family member’s cancer occurred before age
60 then the patient should start 10 years younger.
There will be a Colorectal Cancer Awareness patient education program at
Costco March 4th. If you would like to help please contact Barb Otto at
Harrison’s Oncology education office on 2West.
RELAY FOR LIFE
Relay for Life is a major fundraiser for American Cancer
Society to aid local patients. Teams are now forming in North, Central and
South Kitsap as well as North Mason and Bainbridge Island. Harrison’s
cancer education team will be present at all races and assisting each
organizational team.
REMEMBER: COLORECTAL CANCER IS PREVENTABLE!!! |
Kitsap ColoRectal Surgery, Johnny B. Green, MD, FACS, FASCRS
Eastwood Building, 2528 Wheaton Way, #103, Bremerton, WA 98310
Voice:
(360) 377-4717 -- Fax: (360) 377-4134
www.kitsapcolorectal.com
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