Breast cancer is a complex disease, and accurate diagnosis and treatment planning are crucial for optimal outcomes. But here's where it gets controversial: preoperative magnetic resonance imaging (MRI) has been a hot topic, with its higher sensitivity for detecting cancer foci and potential to improve surgical planning, yet concerns about its impact on mastectomy rates and clinical benefit. This multicentre prospective observational study aims to shed light on this debate, focusing on changes in patient management after preoperative MRI for newly diagnosed breast cancer.
The study reveals that MRI was most often requested for women with dense breasts, and it led to a significant increase in mastectomy rates, except for older women (≥70 years) and those already planned for neoadjuvant therapy. Interestingly, the majority of changes in surgery plans were potentially justified by final pathology findings, suggesting that MRI might be a valuable tool for selected patients. However, the controversy lies in the potential for unnecessary extensive surgery in some cases.
Breast-conserving surgery (BCS) is a common approach, but it relies on accurate preoperative imaging. Conventional imaging, such as mammography and ultrasound, provides good anatomical information, but contrast-enhanced imaging, like MRI, may be superior for local staging. MRI's superior sensitivity is well-known, but its impact on surgical outcomes has been inconsistent in randomized controlled trials (RCTs) and meta-analyses. This study aims to clarify its role in specific patient subgroups.
International studies, including the Multicenter International Prospective Analysis (MIPA) trial, have explored the effects of preoperative MRI on breast cancer surgery. MRI was more likely to be used in younger women, those with lobular pathology, dense breasts, or larger tumours, and those initially planned for mastectomy based on conventional imaging. The study found that MRI led to changes in surgical plans, with a lower reoperation rate in the MRI group compared to conventional staging. However, meta-analyses suggest that preoperative MRI may increase mastectomy rates, but its effects on local and distant recurrence-free survival and other surgical outcomes vary across studies.
The impact of MRI in specific clinical scenarios at the time of cancer diagnosis remains unclear, and access is limited in many settings. In Australia, government funding for MRI is contingent on further data demonstrating its potential to improve treatment planning and outcomes. This study aims to address this uncertainty by characterizing patient subgroups that may benefit from preoperative MRI.
The study recruited women with newly diagnosed breast cancer, for whom the local multidisciplinary team recommended MRI to better plan treatment. Data on patient demographics, reasons for requesting MRI, and pre-MRI treatment plans were collected. The primary outcome was the change in surgical treatment plan after MRI. The study found that high breast density was the most frequent reason for requesting MRI, and changes in breast surgery occurred in about one-third of patients, with an absolute increase in mastectomy rates. Most surgical changes were deemed justifiable by final pathology findings.
The study's findings are consistent with international data, showing that MRI is most frequently used in women with high breast density and younger women. The current Medicare rebate in Australia is available for patients with a discrepancy between clinical and conventional imaging assessments, and the study contributes to defining the role of MRI in improving outcomes in high-risk subgroups. However, the effects of MRI on cancer recurrence remain unknown without long-term follow-up and a larger dataset.
The study has some limitations, including the lack of a comparison group without MRI, and the hypothetical nature of the pre-test management plan. Increasing use of contrast mammography may also impact the advantages of MRI. Despite these limitations, the study provides valuable insights into the potential benefits and controversies of preoperative MRI in breast cancer management, and invites further discussion on its role in improving patient outcomes.
