SCIENTIFIC ADVANCES

Results of Six Imaging Clinical Trials

Findings from six medical imaging clinical trials coordinated by ACRIN were presented during the network’s 2007 Fall Meeting in Arlington, Virginia. Key results presented include:

• ACRIN 6664: The primary results of the National CT Colonography Trial, led by C. Daniel Johnson, M.D., from the Mayo Clinic, demonstrated that CT colonography (CTC) is highly accurate for the detection of intermediate and large polyps and that the accuracy of CTC is comparable to colonoscopy. This clinical trial evaluating CTC as a primary colorectal cancer screening modality is the largest to date, with 2,600 participants.

  

  An early stage colon carcinoma is depicted on axial-slice CTC on the left and in a 3-D CTC reconstruction on the right.

• ACRIN 6666: Wendie Berg, M.D., Ph.D., from American Radiology Services, Johns Hopkins University, and the lead investigator of the Screening Breast Ultrasound in High-Risk Women trial, reported that ultrasound combined with mammography found statistically significantly more cancers compared to mammography alone in the trial’s first-year screening results. However, investigators also found that the risk of false-positive results is higher with screening ultrasound and could remain a barrier to its increased use.

• ACRIN 6659: A study led by Jeffrey Weinreb, M.D., Yale University School of Medicine, on the use of MRI combined with MR spectroscopy (MRS) for staging of prostate cancer at 1.5 T magnet strength found that, overall, no improvement in accuracy was noted for combined MRI/MRS over MRI alone.

• ACRIN 6661: A study led by Damian Dupuy, M.D., Rhode Island Hospital, of radiofrequency ablation (RFA) for treating painful bone metastasis demonstrated that RFA can be safely performed and offers an effective symptomatic treatment option for select patients whose cancer has metastasized to the bone.

• ACRIN 6652: A cost-effectiveness analysis of digital mammography was presented by the study’s lead author, Anna Tosteson, Sc.D., from Dartmouth-Hitchcock Medical Center. She reported that age-targeted digital mammography breast cancer screening appears cost effective. In contrast, universal digital mammography screening is not, at the present time, cost effective based on current reimbursement rates. The analysis data arose from the Digital Mammographic Imaging Screening Trial first reported in 2005.

• ACRIN 6667: A study led by Constance Lehman, M.D., Ph.D., that found that MRI detects cancers in the opposite breast of women newly diagnosed with breast cancer was reported in the March 29, 2007, issue of the New England Journal of Medicine. MRI of women diagnosed with cancer in one breast detected over 90 percent of cancers in the opposite breast that had been missed by mammography and clinical breast exam at initial diagnosis. Given the established rates of mammography and clinical breast exams for detecting cancer in the contralateral breast, adding an MRI scan to the diagnostic evaluation effectively doubled the number of cancers immediately found in these women. The study recruited 1,007 women from 25 institutions who had a recent diagnosis of cancer in one breast. Of these, 969 women completed the study, which began in April 2003. All of the women enrolled had a negative mammogram and negative clinical breast exam of the opposite breast within 90 days prior to the MRI. After receiving an MRI, 33 contralateral breast cancers were diagnosed in the study. Thirty of these tumors, or 91 percent, were diagnosed as a result of MRI. The other three cancers were detected on subsequent mastectomies.

Lehman CD, Gatsonis C, Kuhl CK, Hendrick RE, Pisano ED, Hanna L, Peacock S, Smazal SF, Maki DD, Julian TB, DePeri ER, Bluemke DA, Schnall MD; ACRIN Trial 6667 Investigators Group. MRI evaluation of the contralateral breast in women with recently diagnosed breast cancer. NEJM 2007:356;1295–303.
http://www.ncbi.nlm.nih.gov/pubmed/17392300

A patient already diagnosed with breast cancer in the right breast had a negative mammogram of the left, contralateral breast, while MRI detected that that left breast actually harbored a simultaneous early stage cancer (bright nodules visible in the MRI image to the right).