News from the Fall meeting of ACRIN at the Pentagon

The Fall meeting of ACRIN was held last week at Pentagon City in DC.



Of note was the report from UCSF-led ACRIN study, on the use of breast MRI in the assessment of neoadjuvant chemotherapy -

"MRI is superior to mammography for evaluating the response to neoadjuvant chemotherapy for breast cancer, according to the early results of a trial from the University of California, San Francisco (UCSF) and nine other academic centers in the U.S. The results were presented at last week's American College of Radiology Imaging Network (ACRIN) fall meeting".

The study was developed under ACRIN's protocol 6657, representing the imaging side of the larger I-SPY (Investigation of Serial Studies to Predict Your Therapeutic Response With Imaging and Molecular Analysis) trial aimed at gauging breast cancer treatment response. Sponsored by the Cancer and Leukemia Group B Foundation (CALGB), the I-SPY trial is "testing imaging and tissue-based biomarkers in combination, predicting neoadjuvant response to standard chemotherapy," explained Nola Hylton, Ph.D., a principal investigator from UCSF who discussed the results.

Participants were scanned four times during chemotherapy, including once pretherapeutically, once after the first cycle of chemotherapy, and a third time between the anthracycline and Taxol agents. A fourth scan prior to surgery was intended to detect residual disease and evaluate the post-treatment sensitivity and specificity of MRI. Mammography scans were acquired to coincide with the first and last MRI scans

MRI measurements included morpholgic measurements of the tumors classified according to BI-RADS criteria for breast MRI, including tumor diameter measurements. "We're also measuring by computer the volume of the tumor and the microvascular parameters of the tumor, PE [percent enhancement] and SER [signal enhancement ratio]," used to distinguish malignant tissue, said Hylton.

he investigational software assesses tumor volume quantitatively based on functional rather than anatomic criteria, she explained. "We are measuring something that is based on how these tumors enhance, and assigning [volume] based on an algorithm calling it part of the tumor or not. So it's really a virtual volume [that defines] areas of the image based on function, in this case how the tumors enhance."

The investigators acquired one T1-weighted precontrast and two T2-weighted postcontrast scans, "and from that we looked at the early ratio of enhancement from the early time point to the late time point," she said. This calculation yields the signal enhancement ratio, which distinguishes tumor from nontumor. Another protocol ensures that the direction of diameter measurements remains constant over the course of multiple imaging exams

At the end of surgery, 43% of the patients were complete responders, 38% were partial responders, and 10% demonstrated stable disease. "There were a larger portion of complete responders among those who also received Taxol," she said. "And there were a total of 82 pathologic complete responders, meaning that there was no invasive disease left at pathology. Sixty percent of patients had a complete solid lesion, and 32% had two identifiable lesions in the breast.

Compliance with the study was surprisingly good, especially considering the complexity of the protocol, requiring both biopsy and multiple imaging exams in addition to treatment, she said. In addition, lesion morphology was very similar to a pilot study. There were 36 single masses; 65 multilobulated masses with well-defined margins; 66 lesions with area enhancement, irregular margins, and nodularity; 30 of the same without nodularity; and 19 patients with septal spread.

Once the analysis has been completed, more precise data will be presented at the 2008 RSNA meeting in Chicago.

Researchers Are Investigating Two New Potential Tools for Diagnosing Breast Cancer

Researchers at Jefferson Medical College of Thomas Jefferson University in Philadelphia are investigating contrast-enhanced subharmonic ultrasound as a noninvasive exam that could help physicians make a diagnosis. In subharmonic imaging, pulses are transmitted at one frequency, but only echoes at half that frequency are received

In a study reported in the September 2007 issue of Radiology, researchers tested their technique on 14 women ranging in age from 37 to 66 who had 16 biopsy-proven lesions. The researchers used a GE Logiq 9 ultrasound machine that was modified to perform grayscale subharmonic imaging, transmitting at 4.4 megahertz and receiving at 2.2 megahertz. The women underwent precontrast imaging and imaging using contrast

The researchers’ results using subharmonic imaging were better than conventional ultrasound and mammography. Of the 16 lesions, four were malignant. Mammography had 100% sensitivity and 20% specificity for these lesions. Subharmonic imaging had 75% sensitivity and 83% specificity for the same lesions.

The other tool -
Researchers at Duke University in North Carolina have developed a new scanner that they believe is better at finding early cancers in women than conventional mammography, and it can also be used for diagnosis and monitoring of therapeutic response(s). It is a hybrid between a SPECT and a CT scanner they are collectively calling mammotomography

The researchers have done imaging observer studies using phantoms to compare x-ray digital mammography with CT. “We have been able to show a significant statistical improvement using CT compared to mammography,” Tornai says. “In mammography, you lose a lot of information because you have only a 2D image. With the 3D image that the SPECT/CT scanner produces, lesions become more conspicuous because overlapping tissues are removed. In contrast to x-ray tomosynthesis, a pseudo-3D x-ray imaging modality, the SPECT/CT system produces a uniform 3D image and does not require any breast compression.”

The hybrid scanner that the researchers have built from novel configurations of conventional equipment circles the breast as the patient lies on a specially built table.

The scanner is also able to see areas, including the chest wall, that traditional mammograms may not. They have tested the hybrid scanner extensively with phantoms and has begun successfully scanning subjects with known cancer.

Because SPECT requires IV injection of imaging agents, the SPECT portion of the scanner would not likely be broadly used for routine screening mammography. However, if it proves to be more effective, the hybrid SPECT/CT system might be especially helpful for women who are at high risk for developing breast cancer because of familial history or a genetic predisposition.

Breast SPECT/CT also could be used for women with dense breasts or implants because mammography is known to miss up to 25% of cancers in these women, Tornai says. The scanner and associated imaging procedure also should be less costly to employ than MRI

MRI increases mastectomy rate

Two interesting stories hit the headlines this week. The first concerned breast density, and the fact that passing through the menopause can greatly affect the rate at which a woman's mammographic (breast) density changes over time.
This was a report from the American Journal of Epidemiology
Am. J. Epidemiol. 2008 167: 1027-1036



The researchers retrieved and digitized 5698 mammograms from 1689 women who were imaged in 1990-2003 to evaluate PD in the Minnesota Breast Cancer Family cohort. The women completed two questionnaires, the first in 1990-1996 and the second in 2001, which provided extensive risk factor data. Postmenopausal women showed a decline in PD of 1.0% over a mean of 6.2 years, while premenopausal women showed a decline in PD of 1.8% over a mean of 4.0 years.

Further analysis showed that, before the age of 50 years, postmenopausal women who never used hormones had a higher PD compared with former and current users. After the age of 50 years, women who never used hormones had larger declines in PD than current or former users.

Higher BMI was associated with lower PD among postmenopausal women at any age after adjusting for covariates. And women in the 95th (highest) percentile for baseline PD showed greater declines in PD over time than women in the 5th (lowest) percentile.

You can get a FREE PDF of the paper from - here

The other story was widely reported in the NEW YORK TIMES this Friday. Thanks to press releases, details about the study which will be presented in Chicago at the annual meeting of the American Society of Clinical Oncology, which begins May 30 has got into the media.

The study revealed that "the percentage of women opting for mastectomy rather than lumpectomy began rising sharply after 2003." A possible explanation for the increase is that MRI "detects more possibly cancerous growths than mammography," which "could be causing patients and doctors to conclude that a lumpectomy, which removes just the part of the breast containing the primary tumor, may not be sufficient."

We certainly are doing far more MRIs, but in our case at UCSF, many of these patients are in trials. Wait until we start following the American Cancer Society Guidelines for women at high risk of breast cancer, with the increase in false positives we get, plus the increased anxiety because of family history...........

ARRS MRI Course

The course was excellent, and covered the range of MRI based information with case studies, as well as Jeffrey Weinreb giving an excellent coverage over the debate about NSF and gadolinium based contrast agents

There was one registrant from Cheshire, but never got to see them there.

If this is repeated next year, I would recommend folks considering applying and attending for CME.

Viva Las Vegas!

Well today I was supposed to be travelling to Las Vegas, where the American Roentgen Ray Society (ARRS) are hosting a Practical Breast MRI session at the Westin, similar to that held by the Radiology Academy in Norwich last April.

Weather has conspired against this so far. In California the rain is teeming down and 2 runways have been closed at San Francisco International Airport, with the associated delays, I am now experiencing what most Americans have to put up with on a regular basis. Hopefully will get off before midnight as we have a 7am start tomorrow.

The mid-West are having serious arctic weather right now, just like the UK appear to be having a similar arctic blast for the end of the week.

Does this remind you of the film - 'the day after tomorrow'?