Preoperative contrast-enhanced mammography (CEM) improves the measurement of breast cancer lesion extent compared to conventional imaging, but a major clinical trial found it did not reduce reoperation rates or meet its primary goal of changing treatment in 10% of patients.
- CEM showed the closest agreement with actual tumor size (3.5 mm bias) compared to digital mammography (4.8 mm) and ultrasound (10.7 mm)
- Treatment approach changed in only 8.4% of CEM patients, falling short of the 10% primary outcome target
- Reoperation rates were similar between CEM and control groups (7.9% vs 10%, p=0.39)
- The PROCEM trial enrolled 415 women with early-stage breast cancer across two Swedish medical centers from 2020-2024
- Better diagnostic imaging did not translate into improved surgical outcomes, mirroring results from similar MRI trials
Preoperative contrast-enhanced mammography (CEM) can improve estimating malignant breast lesion extent, according to findings published November 3 in Radiology.
While CEM did not meet the primary trial end point of a 10% treatment change, CEM findings helped avoid reoperation and guided to correct treatments, wrote a team led by Anna Gardfjell, MD, from Skåne University Hospital in Malmö, Sweden.
“With increased clinical confidence in CEM, results suggest that preoperative CEM may help optimize treatment for many patients with breast cancer,” the Gardfjell team wrote.
CEM continues to gain ground in diagnostic breast imaging, with studies showing its performance being on par with MRI. However, there remains a lack of randomized trials assessing CEM’s added value in preoperative breast cancer staging beyond conventional imaging.
Gardfjell and colleagues studied CEM’s added value in the Added Value of Preoperative Contrast Enhanced Mammography in Staging of Malignant Breast Lesions (PROCEM) trial. The study, which took place between 2020 and 2024, enrolled women diagnosed with early-stage breast cancer who were eligible for primary surgery at two breast centers in Sweden. The researchers randomized the women between preoperative CEM and control cohorts.
The team noted the primary outcome being a 10% change in treatment due to preoperative CEM findings.
Final analysis included 415 women with a median age of 66 years who completed the trial. This included 202 women in the CEM group and 213 women in the control group.
Low-energy and recombined contrast-enhanced mammography (CEM) images in a 46-year-old woman recalled from screening due to a palpable and mammographically visible lesion with retraction in the retromamillary area of the right breast. Standard imaging with digital mammography and US had been performed and showed an M4 and U4 12-mm lesion. Core needle biopsy was performed and showed invasive lobular carcinoma (B5). The CEM series—(A) low-energy craniocaudal projection, (B) recombined craniocaudal projection, (C) low-energy mediolateral oblique projection, and (D) recombined mediolateral oblique projection—shows that the main lesion is 16 mm and findings of multifocality consisting of at least six additional lesions with a total malignant extent of 80 mm. Biopsy from one of the additional lesions at a second-look US confirmed invasive cancer. The surgical plan was modified from partial mastectomy to mastectomy. Postoperative histopathologic examination showed multifocal lobular invasive breast cancer with a total extent of 107 mm.RSNA
Treatment approach changed in 17 women in the CEM arm (8.4%) based on CEM findings.
The researchers found no evidence of differences between both patient groups regarding mastectomy (17% vs. 18%; p = 0.78) or reoperation (7.9% vs. 10%; p = 0.39) rates.
Finally, CEM showed the closest agreement with histopathologic malignant extent (bias, 3.5 mm). This outperformed digital mammography and/or tomosynthesis (4.8 mm) and ultrasound (10.7 mm) both overall and in nine of 10 predefined subgroups, except for ductal carcinoma in situ (DCIS).
The authors called for future larger studies to find differences in subgroup comparisons.
“A future study will further assess potential missed opportunities for surgical de-escalation, avoidable mastectomies or reoperations, and rates of additional second-look ultrasound and biopsies, including false-positive and false-negative findings,” they wrote.
The results follow in the footsteps of the Comparative Effectiveness of MRI in Breast Cancer (COMICE) trial, according to an accompanying editorial written by Benoît Mesurolle, MD, from Centre République in Clermont-Ferrand, France, and Mona El Khoury, MD, from the University of Montreal in Canada.
The editorial authors wrote that the scenario presented in the PROCEM trial “closely mirrors that of preoperative MRI.”
“Both trials were preceded by enthusiastic retrospective data: management changes in 18% to 25% of patients for CEM, and a similarly promising literature for MRI. Both then failed to translate this promise into fewer reoperations: adding MRI to conventional assessment did not reduce reoperation rates in COMICE, and neither did adding CEM in PROCEM,” Mesurolle and Khoury wrote. “Both experiences therefore suggest that the added diagnostic value of a contrast-enhanced modality does not necessarily translate into improved surgical outcomes.”
The two added that more prospective and multicentric studies will better clarify CEM’s impact on immediate and long-term outcomes.
Read the full study here.
