title: ACR Appropriateness Criteria pretreatment staging of colorectal cancer.
abstract: Because virtually all patients with colonic cancer will undergo some form of surgical therapy, the role of preoperative imaging is directed at determining the presence or absence of synchronous carcinomas or adenomas and local or distant metastases. In contrast, preoperative staging for rectal carcinoma has significant therapeutic implications and will direct the use of radiation therapy, surgical excision, or chemotherapy. CT of the chest, abdomen, and pelvis is recommended for the initial evaluation for the preoperative assessment of patients with colorectal carcinoma. Although the overall accuracy of CT varies directly with the stage of colorectal carcinoma, CT can accurately assess the presence of metastatic disease. MRI using endorectal coils can accurately assess the depth of bowel wall penetration of rectal carcinomas. Phased-array coils provide additional information about lymph node involvement. Adding diffusion-weighted imaging to conventional MRI yields better diagnostic accuracy than conventional MRI alone. Transrectal ultrasound can distinguish layers within the rectal wall and provides accurate assessment of the depth of tumor penetration and perirectal spread, and PET and PET/CT have been shown to alter therapy in almost one-third of patients with advanced primary rectal cancer. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
authors.affiliation: Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Dewhurst
authors.forename: Max P
authors.initials: MP
authors.lastname: Rosen
authors.forename: Michael A
authors.initials: MA
authors.lastname: Blake
authors.forename: Mark E
authors.initials: ME
authors.lastname: Baker
authors.forename: Brooks D
authors.initials: BD
authors.lastname: Cash
authors.forename: Jeff L
authors.initials: JL
authors.lastname: Fidler
authors.forename: Frederick L
authors.initials: FL
authors.lastname: Greene
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Hindman
authors.forename: Bronwyn
authors.initials: B
authors.lastname: Jones
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Katz
authors.forename: Tasneem
authors.initials: T
authors.lastname: Lalani
authors.forename: Frank H
authors.initials: FH
authors.lastname: Miller
authors.forename: William C
authors.initials: WC
authors.lastname: Small
authors.forename: Gary S
authors.initials: GS
authors.lastname: Sudakoff
authors.forename: Mark
authors.initials: M
authors.lastname: Tulchinsky
authors.forename: Vahid
authors.initials: V
authors.lastname: Yaghmai
authors.forename: Judy
authors.initials: J
authors.lastname: Yee
mesh_terms: D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology* / Q000628:therapy; D003952:Diagnostic Imaging / Q000592:standards*; D006801:Humans; D009367:Neoplasm Staging; D017410:Practice Guidelines as Topic; D011300:Preoperative Care / Q000592:standards*; D011871:Radiology / Q000592:standards