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					Rectal Cancer

Harish Kakkilaya MD
               Importance
• Wide excision of the cancer and surrounding
  structures is usually impossible

• Risk of injury to the sphincter mechanism

• Urogenital system and its innervation lies in
  close proximity

• Reservoir for fecal material
               Epidemiology
• Incidence of colorectal cancer stable in USA since
  1950s
• 147,000 new cases and 57,000 deaths each year
• Third most common and 2nd most lethal cancer in
  both men and women
• Incidence increases after the age 50
• Lifetime risk of 6%
• 6-8% occur before the age 40 years
                      Pathology
•   Adenocarcinoma(95%)
    – Well differentiated
    – Moderately well differentiated
    – Poorly differentiated

•   Carcinoid
•   Lymphoma
•   Melanoma
             Types
• Polypoid
             Types
• Polypoid
               Types
• Polypoid
• Ulcerative
               Types
• Polypoid
• Ulcerative
• Annular
                       Types
•   Polypoid
•   Ulcerative
•   Annular
•   Diffuseley infiltrating
•   Colloid
• Colon cancer is
  three times more
  common than rectal
  cancer
               Risk factors
•   Age: 90% over age 50
• Adenomatous polyps
• Personal or family history of colorectal cancer
or adenoma,
• Personal history of inflammatory bowel disease
(IBD)
• Sporadic” account for 75% of all
  cancers
• A potential genetic influence is identified
  in the remaining 25% of patients
  – Family history (15% to 20%)
  – HNPCC (5%)
  – FAP (>1%)
Adenoma
                     Risk factors
• Age
• Adenomatous Polyps
• Family History
          – Sporadic
          – Familial Adenomatous polyposis: APC gene on 5q(1%)
          – Hereditory nonplyposis colon cancer syndrome(4-6%)
• Peutz-Jeghers syndrome
• Inflammatory Bowel Disease
           • Ulcerative Colitis: 1% per year after 10 year
           • Crohn’s disease
• Diet:   unsaturated animal fats
           • Dimethyl Hydrazine
           • Dietary fiber
           • Alcohol
  Dietary and Lifestyle Risk Factors for Colon and Rectal Cancer




Likelihood of        Decreased Risk                Increased Risk
Association
Probable             Physical activity, folate,    Obesity, smoking,
                     vegetables                    red meat
Possible             Fruit, calcium, vitamin D,    Alcohol,
                     methionine                    processed meat,
                                                   heavily cooked
                                                   meat, iron
Unknown              Fiber supplement              —
           Lymphatic spread
• Lymphatic watershed area: 7 to 8 cm above the anal
  verge
• All lymph above this point drains upward along the
  superior hemorrhoidal vessels
• Below this level there is a dual drainage
• Drainage laterally along the middle hemorrhoid
  vessels to the internal iliac chain of lymph nodes
• And from there by retroperitoneal vessels to the para-
  aortic nodes
• Very distal lesions can drain along the superficial
  perineal lymphatics, toward the superficial inguinal
  lymph nodes
               Diagnosis
• Symptoms:
  – Hematochezia most common presentation
  – Mucus discharge, rectal pain, tenesmus
• Digital rectal examination
• Rigid sigmoidoscopy
  – Distance from the distal edge of the tumor
    to the dentate line measured carefully
             Suspected rectal cancer

                   Look for synchronous Cancers
                   Colonoscopy or BE




Local Evaluation         Regional                 Systemic
Digital rectal                                    CXR
                         Pelvic Exam
Sigmoidoscopy + Biopsy                            CT
                         CT Pelvis
Transanal Ultrasound                              CEA
                         Transanal Ultrasound
                         MRI                      PET Scan
                         PET scan
      Transanal Ultrasound
• Most accurate tool in determining
  tumor(t) stage, accuracy 70-93%

• Each layer of rectal wall identified

• Lymph nodes visualised, but presence
  of cancer can not be predicted
            Duke’s Staging
• A. Cancer growth limited to the wall of the
  rectum
• B. Cancer growth extended through the
  wall
• C. Cancer metastatic to regional lymph
  nodes
                           Staging
Primary Tumor (T)
  TX—Primary tumor cannot be assessed.
  T0—No evidence of primary tumor.
  T1—Tumor invades submucosa.
  T2—Tumor invades muscularis propria.
  T3—Tumor invades through the
  muscularis propria into the subserosa
  T4—Tumor perforates the visceral
  peritoneum or directly invades other
  organs or structures
                         Staging
Regional Lymph Nodes (N)
  N0—No regional lymph node metastasis.
  N1—Metastasis in 1 to 3 pericolic or perirectal lymph nodes.
  N2—Metastasis in 4 or more pericolic or perirectal lymph nodes.
  N3—Metastasis in any lymph node along the course of a named
  vascular trunk.

Distant Metastasis (M)
  M0—No distant metastasis.
  M1—Distant metastasis.
                   Staging
            T      N      M

Stage I     1,2    0      0   Invades Muscularis
                              propria
Stage II    3,4    0      0   Through the
                              Muscularis propria
Stage III   Any   1,2,3   0   Lymph node Mets

Stage IV    Any   Any     1   Distant Mets
           Surgical treatment
• Adequate margin around all facets of the cancer, not
  just the distal margin
• Intestinal continuity should be restored only if the
  anastomosis can be performed with an excellent
  blood supply and no tension
• The sphincter muscle must function adequately
• Colostomy better than incontinence
         Surgical aspects
• Distal resection margin: 2cm is
  adequate
• Wide lateral margin as possible
• Lymphadenectomy: mesorectal excision
          Choice of procedure
• Upper rectal tumors(11-12cm from anal verge)
   – Anterior resection
   – Low anterior resection- below peritoneal reflection
• Middle rectal tumors (6-10cm from anal verge)
   – LAR, APR
   – Chemo-Radiotherapy- Sphincter saving
• Low rectal tumors(0-5cm from anal verge)
   – Neo Adjuvant Chemo Radiation
   – Low Anterior resection with Colo-Anal anastomosis
   – APR, Transanal excision
      Pre op Chemo Radiation
• Preoperative radiation (4500 to 5040 cGy over 5 to 6 weeks)
  combined with chemotherapy (5-fluorouracil and leucovorin)
• Reduces the degree of wall invasion and of lymph node
  involvement in 70% of patients
• Decreased tumor seeding at the time of surgery
• And increased radiosensitivity of cells whose oxygenation is not
  decreased by surgery
• No postsurgical small bowel fixation in the pelvis
• Ability to change the operation from an AP resection to a
  sphincter-preserving low anterior resection with a coloanal
  anastomosis
• In patients with locally advanced/unresectable disease, ability to
  increase the resectability rate (downstaging)
                  Ureters!
• Ureteral catheters extremely helpful
• Cancer involving the bladder or ureter,
  previous pelvic surgery,
• Intraoperative identification and preservation
  easier.
A P Resection
             A-P Resection
• Complete excision of rectum and anus
• Concomitant dissection through the abdomen
  and perineum
• Permanent closure of perineal rafe and
  creation of end colostomy
• The entire left colon is mobilized on its
  mesentery
• The inferior mesenteric artery is ligated at the
  aorta
• Indicated when tumor involves sphincters or
  in patients with poor sphincter control
     Low Anterior Resection
• Consists of removal of sigmoid colon and
  proximal rectum
• Anastomosis in the pelvis below the
  peritoneal reflection
• Use of circular stapling device has improved
  the ease of procedure
• Temporary diverting colostomy is not
  necessary
• Indicated in proximal third and middle third
  rectal tumors
      Coloanal anastomosis
• Transabdominal removal of proximal rectum
  to the level of levator ani muscles
• Transanal excision of the most distal portion
  of rectum
• Inter-sphincteric dissection
• colon is anastomosed to anal verge
• Indicated for low rectal tumors
Low Anterior resection with Colo-
      Anal Anastomosis
• The internal sphincter (continuation of the rectal
  muscularis propria) is resected with the rectum
• Allowing additional 1 cm of distal margin
• Patients rely on the external sphincter for continence
• Allows sphincter preservation for the majority of rectal
  cancer patients
• Reserving abdominoperineal resection for
   – patients with poor preoperative function
   – tumors extending into the external sphincter complex
             Local Resection
• Full thickness excision
• Reapproximation of rectal wall
• Indicated for mobile tumors <4cm , involves <40% of
  rectal wall circumference, located within 6cm of anal
  verge
• Should be T1 or T2 on biopsy, no nodal disease on
  US or MRI
• As palliation in unfit patients
• Transanal, Trans-sacral or Trans-sphincteric
  approach
     Transanal Endoscopic Microsurgery

•   Uses 40mm diameter proctoscope
•   Insufflation with CO2
•   4 ports for instruments
•   Tumors as high as 20cm in rectosigmoid can
    be resected
             Fulguration
• Eradicates the cancer by electrocautery
• Destroys the tumor by creating a full-
  thickness eschar at the tumor site
• Used only for lesions below the
  peritoneal reflection
• Reserved for patients with a prohibitive
  operative risk and limited life
  expectancy
     Endocavitary Radiation
• Both for curative intent and palliation

• Uses a low voltage 50-kV machine,
  delivers radiation through a proctoscope

• Radiation injury is limited to tumor
   Complications of Surgery
• Mortality 1-2%
• Morbidity 10%
• Anastomotic Leakage, Obstruction and
  infection
• Urinary and sexual dysfunction(50-75%)
• Fecal Incontinence
• Locoregional recurrence
         Pre op radiotherapy



1) 2000 cGy for 5 days,    2) 4500 cGy for 5 weeks
   followed by immediate      followed by 7week
   operation                  waiting period
      Post op Radiotherapy

• Post-operative radiotherapy if adequacy
  of resection doubtful

• Post operative radiotherapy has higher
  complications
Neoadjuvant Chemoradiation
• Adding chemotherapy with radiotherapy
• 5-Fluorouracil based regimen
• Modest survival benefit in stage 2 and 3
               Therapy by Stage
stage           preferred                  alternate

T1 N0 M0        Transanal excision         Endocavitary radiation(ECR)
                                           for unfit
T2 N0 M0        APR or AR                  ECR if unfit
                                           Transanal excision for
                                           superficial T2
T3 N0 M0        Pre op Chemo/Radio         APR/AR+ post op Chemo
                APR or AR
T(1,2,3) N1 M0 Pre op Chemo/Radio +
               radical en bloc resction+
               post op Radio
T4 N(0,1) M0    Pre op Radio + En bloc
                Resection
         Metastatic disease
• Single small hepatic lesion: wedge resection
  at the time of surgery for the primary
• Hepatic lobectomy concurrently with colon
  resection not indicated
• Single large hepatic lesion: hepatic resection
  later on
• Isolated pulmonary mets: Pulmonary
  resection
       Obstructing Rectal Cancer

• Not to compromise the chance of cure

• Decompressing colostomy or loop ileostomy

• External radiation for 5 weeks

• After 7 weeks Resection and closure of stoma
    Incurable Rectal Cancer

• Life expectancy >6 months:
  – External radiation followed by palliative
    resection
  – Laser Destruction
    Recurrent Rectal Cancer
• MRI, Immunoscintigraphy, PET Scan

• External radiation

• Pelvic Exenteration
  – Resection of Vagina, Bladder, Sacrum,
    adherent small bowel
               Prognosis
• Stage I disease, more than 90% of patients
  surviving at 5 years.
• For Stage II disease, 60 and 80%
• Stage III, from 20 to 50%
• Distant metastases, fewer than 5% of patients
  survive for 5 years
              Follow-Up
• Up to 50% will develop recurrence
• 80% of these will occur within 2 years
  – History and physical
  – CEA, LFT, CXR
  – CT Abdomen, pelvis
  – Transrectal Ultrasound
  – Colonoscopy
                Screening
•   Beginning at age 50, both men and women
    should follow one of these five testing
    schedules:

•   Yearly fecal occult blood test (FOBT)*
•   Flexible sigmoidoscopy every 5 years
•   Yearly fecal occult blood test* plus flexible
    sigmoidoscopy every 5 years**
•   Double-contrast barium enema every 5 year
•   Colonoscopy every 10 years
       Screening for high risk
             patients
• Patients with adenomatous polyps removed- repeat
  colonoscopy at 3 years
• Patients with colorectal cancer resected: colonoscopy
  within 1 year, if normal every 5 years
• F/H of FAP: Flexible sigmoidoscopy every year
  starting at puberty
• F/H of HNPCC: Colonoscopy every 1-2 years,
  starting at 20-30, then yearly after 40
• IBD: Colonoscopy every 1-2 years, after 8 years of
  disease
Thank you

				
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posted:7/27/2011
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