surgical management of ca anal canal

1. Management of
Carcinoma Anal Canal
DR. JUNISH BAGGA
MODERATOR- DR.M.S.UPPAL

2. Development
• During the 6th week of gestation
• Terminal part of hindgut is called
cloaca
• It is divided by the urorectal
septum into rectum and urogenital
sinus
• Distal anal canal is derived from
infolding of the ectoderm which
fuses with the rectum.
• The dentate line divides the
hindgut from the ectodermal
distal anal canal.

3. Anatomy
• Funnel shaped extension of
pelvic floor
musculature
• 3-4 cms
• Anorectal ring -> anal verge
• Anorectum – anal canal and the
surrounding structures-
• distal rectum
• anal sphincters
• anal canal
• perianal skin

4. Divided into three parts-
1. Upper mucous part(15mm)- 8- 14
folds called anal columns of
morgagni.
Between each 2 columns – anal
crypts
2. Middle part(15mm)- lined by
mucous membrane.
Mucosa has a bluish appearance.
Sensations of heat, cold, touch,
pain
3. Lower cutaneous part(8mm)- true
skin containing sweat and
sebaceous glands.

5. Arterial supply -
• Superior rectal
artery
Inf. Mesenteric
artery
• Middle rectal
artery
• Internal iliac artery
• Inferior recal
artery- inf.
Pudendal atrery

6. Venous drainage
• Superior rectal vein
• Middle rectal vein
• Inferior rectal vein

7. Lymphatic Drainage

8. • Main anatomical reference points
1. Anal verge- junction b/w anal and
perianal skin
2. Dentate line- true mucocutaneous
junction.
1-1.5 cms above anal verge.
Transition zone of 6-12mm
columnar>squamous
3. Anorectal ring- upper border of
sphincteric complex.
Sling- puborectalis muscle

9. Histology
• Columnar epithelium
• ATZ – anal transition zone (1-
2cm)
Columnar cells with variable
amounts of squamous metaplasia
• Non-hair bearing squamous
epithelium
• Perianal skin

10. Overview
• 2.4 % of all GI malignancies
• Anal canal cancer most commonly develops in patients 50 to 60 years
of age.
• Peak incidence is in the 7oth decade of life but highly variable
• More common in women
• Squamous cell ca. is the most common – 80%
• Multimodality treatment with radiation and chemotherapy has
replaced APR and wide local excision

11. Incidence
• Incidence of anal cancer has nearly doubled
in the last two decades
• Mirrors the rise in HIV infection
• It is thought to have a viral etiology similar
to that of cervical cancer.
• There is a slight female predominance with
1. 7 cases per 1 00,000 women compared
with 1 .4 per 1 00,000 men per year

12. Risk factors
• HPV (human PapillomaVirus)
• Female gender (many series of data)
• HIV infection
• Sexual promiscuity- particularly receptive anal intercourse
• Smoking
• Chronic inflammation

13. Classification
• Anal cancers occur between the
anal verge and 2 cm beyond the
dentate line; tumors occurring
further from the dentate line are
called rectal cancers.
• Because of complex histology,
classification has always been
confusing
• 3 main anatomic regions
• Intra-anal –cant be visualized or
with slight retraction of buttocks
• Perianal- fully visible and lie within
5cms of anal opening
• Skin – outside this 5cm radius

14. Anal Intraepithelial Neoplasms- AIN
• Pre-cancerous lesions of the anal canal
• Includes
• Carcinoma in situ
• Bowen’s disease
• Anal dyaplasia
• Squamous intraepithelial lesion
• Same spectrum of pathology

15. AIN
• AIN can be divided into
• LSILs- low grade squamous intraepithelial lesions
• HSILs- high grade intraepithelial lesions
• Invasive cancer
• In European literature, HSIL is known as AIN-3
And LSIL is known as AIN-1 and 2
• The true incidence of HSIL and its resultant progression to invasive
SCC are not clearly known

16. Pathology
WHO classification of malignant epithelial tumors of the anal canal
• Squamous cell carcinoma and its variants
1. Transitional cell ca.
2. Basaloid ca
3. Mucoepidermoid ca.
• Adenocarcinoma
• Small cell ca.
• Undifferentiated ca.
More distal the tumor, more likely it is to contain keratinizing cells.
These tumors arise
from ATZ and are
grouped together as
Cloacogenic.

17. Pathology
• Anal cancers occur between the anal verge and 2 cm beyond the
dentate line; tumors occurring further proximal are called rectal
cancers.
• Adenocarcinomas can arise from anal crypts and should be treated as
a rectal cancer though with a higher risk of inguinal node spread,
given their location and lymphatic flow compared with rectal
adenocarcinomas.

18. Pathology
• Primary anal melanoma is a rare tumor that accounts for only 1% of
all anal cancers. Anal melanoma is similar to melanoma of the skin
and is characterized by the distant spread of disease. Outcome is
poor after wide local excision or abdominoperineal resection, with
just a 10% survival in most series at 5-year follow-up.
• Perianal skin and anal margin tumors include squamous cell
carcinoma, giant condyloma (verrucous carcinoma), basal cell
carcinoma, Bowen disease, and Paget disease.

19. Pathways of tumor spread
• Direct extension to surrounding tissue
• Lymphatic dissemination to pelvic and inguinal lymph nodes
• Hematogenous spread to distant viscera
At diagnosis, about half of all anal cancers have been found to invade
anal sphincter or surrounding soft tissue. Although Denonvillier’s fascia
is an effective barrier to prostatic invasion in men, direct extension to
the rectovaginal septum is a common occurrence in women.

20. Pathways of tumor spread
• The inguinal nodes are the
primary drainage basin for that
part of the anal canal distal to
the dentate line.
• Lymphatic drainage around the
dentate line occurs to lymphatic
plexuses of the rectal mucosa
and along the pathway of the
inferior and middle
hemorrhoidal vessels to
obturator and hypogastric
lymph nodes.

21. Clinical presentation
• The most common presenting symptoms are bleeding (45%) and anal
pain(30%). Other less common symptoms include pruritus , palpable
mass ,anal swelling and changes in bowel habits are the main
symptoms.
• It is common for patients and their physicians to attribute such
symptoms to hemorrhoids for many months preceding the diagnosis,
underscoring the importance of performing a simple anorectal
examination for patients with such symptoms.

22. Diagnostic Workup
• PET imaging is useful in further
evaluating the extent of the
primary tumor and the presence of
regional lymph node metastases,
and distant metastases, as well as
in evaluating the response to
therapy.
• For patients with HIV risk factors, a
determination of HIV status should
be made before the initiation of
therapy.
• Female patients should be
subjected to a gynecologic
examination to exclude other HPV-
associated cancers.

23. HRA – high resolution anoscopy
• Direct corollary of cervical pap
smear
• Diagnostic and screening in
high risk populations
• Gauze soaked in 3%acetic acid
• 3-25 times magnification
• Suspicious lesions can be
destroyed by electrocautery

24. Staging, AJCC TNM STAGING

25. Staging
• In contrast to staging parameters for other GI
lesions it is based on size rather than depth of
invasion
• Direct invasion of the rectal wall, perirectal skin,
subcutaneous tissue, or the sphincter muscle(s) is
not classified asT4.
• Anal margin tumors are staged and treated same
as skin cancers.

26. Management
• Operative therapy for anal canal SCC has largely been supplanted by
chemoradiation and is now exception rather than the rule.
• Multi modality treatment- chemotherapy and radiation
• Surgery is reserved for patients
• those do not respond to chemo radiation
• those with recurrence
• Those who require diversion colostomy
• Inguinal lymph node dissection

27. Chemo radiation
• Norman Nigro revolutionized the treatment
• 5-FU, Mitomycin-C, along with radiotherapy
• 30gy given in 15 sessions over 3 weeks, 5FU was given for first 4 days
as a continuous infusion, repeated on 29th through 32nd days
• Intensity modulated radiotherapy

28. Inguinal lymph nodes metastasis
• Should be confirmed by FNAC
• Surgical clearance is palliative
• Currently, it is treated with chemotherapy and radiation concurrently
with primary tumor
• Some studies have shown better survival following therapeutic
inguinal lymphnode dissection

30. APR
• Involves en bloc excision of the tumor as well as surrounding lymph
nodes and the anal sphincters, resulting in a permanent colostomy
• Traditionally it has been used to treat distal rectal cancers.
• Morbidity of 61% and mortality of 0-6.9%

31. Pre- Op preparation
• Bowel prepration
• clear liquid diet 2 days prior to surgery
• Use of laxatives, enemas
• Antibiotics- neomycin 1gm, erythromycin base 1g; 1,2,10pm
• Mechanical cleansing decreases the total volume of stool in
the colon but the concentration of bacteria remains the
same.
• Systemic antibiotics
• DVT prophylaxis

32. Peri-operative
• Epidural catheter
• Compression devices
• DVT prophylaxis- 5000 units
heparin
• Cefazolin + metronidazole
• Modified lithotomy position
• History of previous surgery or
hydronephrosis- B/L DJ stent
insertion

33. Technique
• Total mesorectal excision
• Laterally, sigmoid mobilization
by scoring white line of toldt
• Ureters must be identified and
preserved
• Colon is divided at the level of
sigmoid-descending junction
• Superior rectal artery +
descending branch of left colic
artery ligated

34. TME – total mesorectal excision
• Proper plane of dissection at the sacral promontory
• Location of sympathetic nerves along pelvic brim
• Rectum is retraced anteriorly and sharp dissection is done inferiorly
to the coccyx
• Anterior and lateral dissections are then carried out after posterior
dissection has been completed
• Care should be taken to preserve hypogastric plexus on the pelvic
side walls(helps in avoiding post op potency/ urinary problems)

35. Mobilization of
rectum
• Peritoneal incision of the
pelvis
• Rectum reflected anteriorly
and posterior avascular
plane entered between the
presacral fascia of waldayer
and fascia propria of the
rectum
• Division of lateral stalks

36. Perineal dissection
• Anal canal closed with a
purse string suture
• Anococcygeal ligament is
divided anterior to the
coccyx through which
scissors are used to gain
entrance into the pelvis

37. Perineal dissection
• Lateral transection of
levator ani muscles
• Anterior transection of
rectourethralis,
puborectalis,
pubococcygeus
• Removal of rectum through
perineal wound
• Closure in multiple layers
with drains in place.

38. Complications
• Perineal wound complications
• Stoma complications-
• ischemia,
• retraction,
• hernia,
• stenosis,
• prolapse

39. Prognosis
• Strong correlation
between tumor size,
lymphatic spread and
prognosis
• Overall survival is
diminished when tumor
size is greater than 5 cms
• 1-2cms- survival 78%
• 3-5cms- survival 55%
• Greater than 6cms, only 40%
• Regional metastasis is a
poor prognostic indicator.

40. ThankYou