Contrast mammography useful substitute to MRI for assessing treatment response in breast cancer
Italy: In a recent study, the researchers suggest that contrast-enhanced mammography (CEM) is a useful alternative to supplemental MRI for assessing treatment response in breast cancer where MRI is contraindicated or not tolerated.
The study, published in the American Journal of Roentgenology showed that following neoadjuvant therapy (NAT) for breast cancer, CEM, and MRI yielded comparable assessments of lesion size (both slightly overestimated vs pathology) and RECIST categories. Also, there was no significant difference in specificity for pathologic complete response (pCR). However, MRI had higher sensitivity for pCR.
In various clinical settings, contrast-enhanced mammography is rapidly expanding as a credible alternative to MRI. D. Bernardi, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano (Milan), Italy, and colleagues, therefore, conducted the study to compare CEM and MRI for neoadjuvant therapy assessment in breast cancer patients in a prospective study.
The study included 51 patients (mean age, 46±11 years) with biopsy-proven breast cancer from May 2015 to April 2018 who were candidates for NAT. Subjects underwent both CEM and MRI before, during, and after NAT (pre-NAT, mid-NAT, and post-NAT, respectively). Post-NAT CEM included a 6-minute delayed acquisition.
CEM examinations were reviewed by one breast radiologist and MRI examinations were reviewed by one breast radiologist with experience in MRI. The radiologists assessed for the presence of an enhancing lesion. In cases of detection of an enhancing lesion, its size was measured. RECIST version 1.1 response assessment categories were derived. Pathologic complete response (pCR) was defined as absence of invasive cancer or DCIS.
Salient findings of the study include:
- pCR was achieved in 16/51 patients. CEM yielded systematically lower size versus MRI (mean difference: pre-NAT, -0.2 mm; mid-NAT, -0.7 mm; post-NAT, -0.3 mm).
· All post-NAT imaging tests yielded systematically larger size versus pathology (CEM, 0.8 mm; MRI, 1.2 mm; delayed CEM, 1.9 mm).
· Of 12 patients with residual DCIS, an enhancing lesion was detected in 7 on post-NAT CEM, 8 on post-NAT MRI, and 9 on post-NAT delayed CEM.
· Agreement of RECIST response categories between CEM and MRI, expressed as kappa, was 0.791 mid-NAT and 0.871 post-NAT.
· For detecting pCR by post-NAT imaging, sensitivity and specificity were 81% and 83% for CEM, 100% and 86% for MRI, and 81% and 89% for delayed CEM.
· Sensitivity was significantly higher for MRI than CEM and delayed CEM; remaining comparisons were not significant.
"While MRI remains the preferred test for NAT monitoring, the results support CEM as a useful alternative when MRI is contraindicated or not tolerated," the authors conclude.
Citation: American Journal of Roentgenology: -. 10.2214/AJR.22.27756
