Colorectal cancer is a carcinoma arising from the luminal surface of the colon.
It is the 2nd most common cancer in women and third most common cancer in male worldwide. It commonly arises from adenomatous polyps.
It is strongly linked to age with 83% occurring in people ≥60 years old.
Rectal cancer is defined as cancerous lesions located within 12 cm of the anal verge.


Resectable Nonmetastatic Rectal Cancer

  • Associated with decreased rates of local recurrence for rectal cancer
  • Risks include increased hematologic toxicities, radiation-induced injury

Preoperative versus Postoperative Radiation Therapy

  • Preoperative radiation therapy (along with chemotherapy) is recommended for those with stage II & III rectal cancer
  • Advantages of preoperative radiation therapy include:
    • Increased rate of sphincter preservation
    • Increased sensitivity to radiation therapy of surgically-naive tissues
    • Avoiding radiation-induced injury that can arise from post-surgical adhesions
    • Increases the likelihood that an anastomosis with a healthy colon can be done
  • Disadvantage of preoperative radiation therapy is the possibility of overtreating early-stage tumors that do not require radiotherapy
  • Postoperative radiation therapy is recommended when stage I rectal cancer has been upstaged to stage II or III after pathologic review of the surgical specimen

Intraoperative Radiotherapy (IORT)

  • For patients with T4 tumors or recurrent cancers, or if margins are positive or very close
  • Involves direct exposures of tumors to radiation therapy intraoperatively while normal structures are removed from the field of treatment
  • Considered as an additional boost to facilitate surgery
  • If unavailable, brachytherapy &/or 10-120 Gy of radiation may be considered soon after resection, prior to adjuvant chemotherapy

Metastatic Colorectal Cancer

Arterial Radioembolization

  • While toxicity is relatively low, evidence supporting its use is still lacking

External Beam Radiation Therapy (EBRT)

  • May be considered in highly selected cases where patients have limited number of liver or lung metastases or in symptomatic patients or in the setting of a clinical trial
Digital Edition
Asia's trusted medical magazine for healthcare professionals. Get your MIMS Gastroenterology - Malaysia digital copy today!
Editor's Recommendations
Most Read Articles
31 Jan 2018
Treatment with proton pump inhibitors (PPIs) appears to increase the risk of death during hospitalization in the presence of pyogenic liver abscess, according to a study.
28 Jun 2017
Intra- and/or postoperative blood transfusion (BT) may increase the risk of postoperative infections complications in patients with Crohn’s disease (CD), according to a study.
18 Oct 2016
EndoClot has been shown to help in the management of gastrointestinal (GI) bleeding whether as a monotherapy or in combination with other techniques from oozing bleeding type or lower, according to a recent study.
Stephen Padilla, 22 Dec 2017
A correlation exists between coeliac disease and a heightened risk of pneumococcal infection, according to a recent study, adding that vaccination must be considered for those with the disease, especially those aged 15‒64 years who have not received the scheduled pneumococcal vaccination series when they were young.