colorectal%20cancer
COLORECTAL CANCER
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.

Radiotherapy

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
  • Alternative for highly-selected patients with predominantly hepatic metastases & with chemotherapy-resistant or refractory disease

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!
Sign In To Download
Editor's Recommendations
Most Read Articles
Pearl Toh, 3 days ago
First-line therapy with the BTK* inhibitor ibrutinib plus the anti-CD20 immunotherapy rituximab confers significant survival advantage over the current gold-standard regimen of fludarabine, cyclophosphamide, and rituximab (FCR) for young, fit patients with treatment-naïve chronic lymphocytic leukaemia (CLL), according to the E1912 trial, a large cooperative group study supported by the US National Cancer Institute.
6 days ago
Percutaneous coronary intervention (PCI) displays comparable rates of mortality and serious composite outcomes but a higher rate of target-vessel revascularization at 10 years relative to coronary artery bypass grafting (CABG) in patients with significant left main coronary artery (LMCA) disease, reports a study. On the other hand, CABG delivers lower mortality and serious composite outcome rates compared with PCI with drug-eluting stents after 5 years.
Pearl Toh, 07 Dec 2018
Apixaban slashes the risk of recurrent venous thromboembolism (VTE) by 90 percent in cancer patients compared with the low-molecular-weight heparin (LMWH) dalteparin, with no increase in major bleeding risk, according to the ADAM VTE study presented at ASH 2018.
2 days ago
Rates of major bleeding events are similar across cancer patients taking direct oral anticoagulants (DOAC), low-molecular-weight heparin (LMWH) or vitamin K antagonist (VKA), with gastrointestinal bleeding being the most frequent event, a recent study has shown. In addition, DOAC and LMWH recorded higher rates of venous thromboembolism than earlier studies.