Anorectal: Rectal Cancer

Rectal Cancer

Colorectal Polyp Work-Up

  • *See Large Intestine: Colon Polyps
  • Staging: MRI or Endoscopic US (EUS)
    • Comparison:
      • EUS is More Accurate at Defining T-Stage (Decreases with Higher Staging)
      • MRI Better Defines the Extent of Mesorectal Fascia Involvement & Radial Margin of Larger Tumors
    • CT for Distant Mets but Not Sufficient for T/N Status

Rectal Cancer 1

Rectal EUS – Layers 2

Rectal EUS – Sphincters 2

Rectal Cancer on EUS 2

Rectal Cancer on MRI 3

TNM Staging

  • Comparison:
    • Rectal Cancer Same as Colon
    • Anal Cancer Different
  • TNM
  T N M
1 Submucosa 1a – 1
1b – 2-3
1c – Discrete Tumor Nodules in Lymph Drainage Area without Identifiable Lymph Node Tissue		 1a – One Distant Organ
1b – ≥ 2 Distant Organs
1c – Peritoneal Mets
2 Into Muscularis Propria 2a – 4-6 LN
2b – ≥ 7 LN
3 Into Serosa
4 4a – Through Serosa
4b – Into Adjacent Tissue/Organs
  • Staging
  T N M
I   T1-2 N0 M0
II A T3 N0 M0
B T4a N0 M0
C T4b N0 M0
III A T1 N1-2a M0
  T2 N1 M0
B T1 N2b M0
  T2 N2 M0
  T3 N1-N2a M0
  T4a N1 M0
C T3 N2b M0
  T4a N2 M0
  T4b N1-2 M0
IV A Any T Any N M1a
B Any T Any N M1b
C Any T Any N M1c

Rectal Cancer – Treatment

Treatment

  • Primary Tx: Surgical Resection
  • May Consider Wide Local Excision (WLE) if All Criteria Are Met

Transanal/Endoscopic WLE

  • Indication Criteria (Lowest Risk of LN Mets):
    • T1
    • < 3 cm
    • < 30% Circumference
    • < 8 cm from Verge
    • Mobile
    • No Lymphatic Invasion
    • No Mucin Production
  • Considerations:
    • Position Patient So that the Lesion in Lying Dependent
    • Full-Thickness
    • Goal Margin: 10 mm
    • Does Not Include a Lymphadenectomy
  • Higher Local Recurrence Rates than Transabdominal Resection

Resection

  • Procedure:
    • *See Anorectal: Proctectomy
    • Upper-Mid Rectum: Low Anterior Resection (LAR)
      • Preserves Sphincter
    • Low Rectum: Abdominoperineal Resection (APR)
      • Loss of Sphincter Requiring Permanent Colostomy
  • Concepts:
    • Ensure a Total Mesorectal Excision (TME)
    • Margins:
      • Proximal: 5 cm
      • Distal: 1-2 cm
        • *Historically Required 5 cm Margins for LAR
        • APR If Unable to Achieve Margins
    • Goal LN: 12

Neoadjuvant Therapy

  • Neoadjuvant Chemotherapy & Radiation
    • Chemo Regimens: 5-FU, FOLFOX or CAPEOX
  • Indications: Stage ≥ II (T3 or N+)
  • Resection Timing: After 2-3 Months
  • Goals:
    • If Stage II/III – Attempt Preserve Sphincter Function
    • If Stage IV – Attempt for APR Instead of Only Colostomy

Adjuvant Therapy

  • Adjuvant Chemo:
    • Chemo Regimens: 5-FU, FOLFOX or CAPEOX
    • Indications:
      • T3 if Threatened Circumferential Resection Margin
      • T4
      • N+
  • Adjuvant XRT: Never Indicated

LAR 4

APR 4

References

  1. Tsukada T, Nakano T, Matoba M, Sasaki S, Higashi K. False-Positive Mediastinal Lymphadenopathy on 18F-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography after Rectal Cancer Resection: A Case Report of Thoracoscopic Surgery in the Prone Position. Case Rep Oncol. 2011 Sep;4(3):569-75. (License: CC BY-NC-ND-3.0)
  2. Kim MJ. Transrectal ultrasonography of anorectal diseases: advantages and disadvantages. Ultrasonography. 2015 Jan;34(1):19-31. (License: CC BY-NC-3.0)
  3. Klessen C, Rogalla P, Taupitz M. Local staging of rectal cancer: the current role of MRI. Eur Radiol. 2007 Feb;17(2):379-89. (License: CC BY-NC-2.0)
  4. Terrone DG, Lepanto L, Billiard JS, Olivié D, Murphy-Lavallée J, Vandenbroucke F, Tang A. A primer to common major gastrointestinal post-surgical anatomy on CT-a pictorial review. Insights Imaging. 2011 Dec;2(6):631-638. (License: CC BY-2.0)