ACR Appropriateness Criteria® on Colorectal Cancer Screening

The role of virtual colonoscopy in colorectal screening

Colorectal cancer is the second leading cause of cancer-related deaths in the United States. The earlier colorectal cancer is detected, the better chance a person has of surviving 5 years after being diagnosed, emphasizing the need for effective and regular colorectal screening. Computed tomographic colonography has repeatedly demonstrated sensitivities equivalent to the current gold standard, optical colonoscopy, in the detection of clinically relevant polyps. It is an accurate, safe, affordable, available, reproducible, quick, and cost-effective option for colorectal screening and should be considered for mass screening.

The time has arrived for national reimbursement of screening CT colonography

OBJECTIVE

CT colonography (CTC) has been fully validated as an accurate screening test for colorectal carcinoma and is being disseminated globally. There is an abundance of new literature addressing the prior concerns of the U.S. Preventive Services Task Force and the Centers for Medicare & Medicaid Services. Specific areas related to radiation dose, extracolonic findings, and generalizability of CTC to senior patients are discussed.

CONCLUSION

The time has arrived for national reimbursement of CTC in the United States.

Suspected extracolonic neoplasms detected on CT colonography: literature review and possible outcomes

RATIONALE AND OBJECTIVES

This study summarizes the literature on the detection of cancer among indeterminate extracolonic findings on computed tomographic (CT) colonography in five targeted organs.

MATERIALS AND METHODS

We searched PubMed for English-language literature published between January 1, 1994, and December 31, 2010. We describe extracolonic findings in the kidney, lung, liver, pancreas, and ovary suspect for malignancy as they are associated with high mortality. For each organ, we calculated the median prevalence, positive predictive value (PPV), and false positive rate of malignancy and a pooled false-positive rate across studies.

RESULTS

Of 91 publications initially identified, 24 were eligible for review. Indeterminate renal masses on CT colonography had 20.5% median PPV and low pooled false positive rate of 1.3% (95% confidence interval 0.6-2.0). In contrast, indeterminate masses of the lung, liver, pancreas, and ovary had low PPV (median values ranged from 0% to 3.8%). Indeterminate masses of the ovary resulted in the highest pooled false-positive rate of 2.2%. Results were similar in studies of both screening and nonscreening populations. We estimated the probability of false positive results through the detection of significant extracolonic findings as 46 per 1000 for men and 68 per 1000 for women.

CONCLUSIONS

Indeterminate renal masses newly detected on CT colonography have an estimated one in five chance of malignancy and therefore warrant further follow-up to provide a definitive diagnosis. Conversely, indeterminate masses of the lung, liver, pancreas, and ovary are associated with high false positive rates and merit more conservative clinical follow-up.

Advances in CT Colonography for Colorectal Cancer Screening and Diagnosis

CT colonography (CTC) is a validated colorectal cancer test that provides an additional minimally-invasive screening option which is likely to be preferred by some patients. Important examination prerequisites include adequate colonic cleansing and distention. Tagging of residual material aids in the differentiation of true polyps from stool. Low radiation dose technique should be employed routinely for screening studies. Readers must be skilled in the use of both 2D and 3D interpretation methods.

The second ESGAR consensus statement on CT colonography

Objective

To update quality standards for CT colonography based on consensus among opinion leaders within the European Society of Gastrointestinal and Abdominal Radiology (ESGAR).

Material and methods

A multinational European panel of nine members of the ESGAR CT colonography Working Group (representing six EU countries) used a modified Delphi process to rate their level of agreement on a variety of statements pertaining to the acquisition, interpretation and implementation of CT colonography. Four Delphi rounds were conducted, each at 2 months interval.

Results

The panel elaborated 86 statements.

In the final round the panelists achieved complete consensus in 71 of 86 statements (82 %). Categories including the highest proportion of statements with excellent Cronbach's internal reliability were colon distension, scan parameters, use of intravenous contrast agents, general guidelines on patient preparation, role of CAD and lesion measurement.

Lower internal reliability was achieved for the use of a rectal tube, spasmolytics, decubitus positioning and number of CT data acquisitions, faecal tagging, 2D vs. 3D reading, and reporting.

Conclusion

The recommendations of the consensus should be useful for both the radiologist who is starting a CTC service and for those who have already implemented the technique but whose practice may need updating.

Key Points

• Computed tomographic colonography is the optimal radiological method of assessing the colon

• This article reviews ESGAR quality standards for CT colonography

• This article is aimed to provide CT-colonography guidelines for practising radiologists

• The recommendations should help radiologists who are starting/updating their CTC services