Magnetic resonance imaging before breast cancer surgery: results of an observational multicenter international prospective analysis (MIPA)

Abstract

Objectives Preoperative breast magnetic resonance imaging (MRI) can inform surgical planning but might cause overtreatment by increasing the mastectomy rate. The Multicenter International Prospective Analysis (MIPA) study investigated this controversial issue. Methods This observational study enrolled women aged 18–80 years with biopsy-proven breast cancer, who underwent MRI in addition to conventional imaging (mammography and/or breast ultrasonography) or conventional imaging alone before surgery as routine practice at 27 centers. Exclusion criteria included planned neoadjuvant therapy, pregnancy, personal history of any cancer, and distant metastases. Results Of 5896 analyzed patients, 2763 (46.9%) had conventional imaging only (noMRI group), and 3133 (53.1%) underwent MRI that was performed for diagnosis, screening, or unknown purposes in 692/3133 women (22.1%), with preoperative intent in 2441/3133 women (77.9%, MRI group). Patients in the MRI group were younger, had denser breasts, more cancers ≥ 20 mm, and a higher rate of invasive lobular histology than patients who underwent conventional imaging alone (p < 0.001 for all comparisons). Mastectomy was planned based on conventional imaging in 22.4% (MRI group) versus 14.4% (noMRI group) (p < 0.001). The additional planned mastectomy rate in the MRI group was 11.3%. The overall performed first- plus second-line mastectomy rate was 36.3% (MRI group) versus 18.0% (noMRI group) (p < 0.001). In women receiving conserving surgery, MRI group had a significantly lower reoperation rate (8.5% versus 11.7%, p < 0.001). Conclusions Clinicians requested breast MRI for women with a higher a priori probability of receiving mastectomy. MRI was associated with 11.3% more mastectomies, and with 3.2% fewer reoperations in the breast conservation subgroup. Key Points • In 19% of patients of the MIPA study, breast MRI was performed for screening or diagnostic purposes. • The current patient selection to preoperative breast MRI implies an 11% increase in mastectomies, counterbalanced by a 3% reduction of the reoperation rate. • Data from the MIPA study can support discussion in tumor boards when preoperative MRI is under consideration and should be shared with patients to achieve informed decision-making.

The potential of predictive and prognostic breast MRI (P2-bMRI)

“…P2-bMRI may transform breast MRI in a one-stop shop solution providing both diagnostic and predictive/prognostic information. While the indication for preoperative MRI is still the subject of debate, it is already regularly performed in clinical practice [9,10,12]. In these patients, the data required for P2-bMRI are readily available, and costly additional investigations are not required.…”

“…The only exception concerns the role of breast MRI in preoperative locoregional staging. The final results of a large multinational investigation (the MIPA study) recently provided important real-world data on this matter [10,12], but this indication remains a matter for debate.…”

Breast Magnetic Resonance Imaging for Patients With Newly Diagnosed Breast Cancer: A Review

“…More recently, an observational multicenter international prospective analysis (MIPA) including 5,896 patients from 27 centers found that the MRI group had a higher overall mastectomy rate (36.3% vs. 18.0%, p < 0.001) compared with that of the no-MRI group (mammography with ultrasound) [ 21 ]. They reported that the planned mastectomy rates were 22.4% and 14.4% ( p < 0.001) in the MRI and no-MRI groups, respectively.…”

“…Therefore, results of conventional imaging suggested the necessity of mastectomy in 67% of women who finally underwent mastectomy, indicating that MRI was used to confirm a surgeon’s decision to perform mastectomy based on conventional imaging. The additional first-line mastectomy rate after MRI was 11.3%, and the MRI group had a reoperation rate of only 3.2% (8.5% and 11.7%, p < 0.001) [ 21 ]. The results from the MIPA study are in line with those of POMB and IRCIS trials in terms of the reoperation rates, which reduced from 15% to 5% and from 27% to 20%, respectively.…”

Costing analysis to introduce a Contrast Enhanced Mammography service in place of existing breast MRI service for local staging of breast cancer

“…larger and multi-focal tumours, rather than the accuracy of MRI per se. 4 Therefore, careful patient selection for preoperative MRI is key. This is recognised in national guidance, which states that breast MRI is only indicated for loco-regional staging under the following circumstances: 5 1.…”