Meta-analysis of pre-operative magnetic resonance imaging (MRI) and surgical treatment for breast cancer

Abstract

Background: Although there is no consensus on whether pre-operative MRI in women with breast cancer (BC) benefits surgical treatment, MRI continues to be used pre-operatively in practice. This meta-analysis examines the association between pre-operative MRI and surgical outcomes in BC.

Methods: A systematic review was performed to identify studies reporting quantitative data on pre-operative MRI and surgical outcomes (without restriction by type of surgery received or type of BC) and using a controlled design. Random-effects logistic regression calculated the pooled odds ratio (OR) for each surgical outcome (MRI vs. no-MRI groups), and estimated ORs stratified by study-level age. Subgroup analysis was performed for invasive lobular cancer (ILC).

Results: Nineteen studies met eligibility criteria: 3 RCTs and 16 comparative studies that included newly diagnosed BC of any type except for three studies restricted to ILC. Primary analysis (85,975 subjects) showed that pre-operative MRI was associated with increased odds of receiving mastectomy [OR 1.39 (1.23, 1.57); p < 0.001]; similar findings were shown in analyses stratified by study-level median age. Secondary analyses did not find statistical evidence of an effect of MRI on the rates of re-excision, re-operation, or positive margins; however, MRI was significantly associated with increased odds of receiving contralateral prophylactic mastectomy [OR 1.91 (1.25, 2.91); p = 0.003]. Subgroup analysis for ILC did not find any association between MRI and the odds of receiving mastectomy [OR 1.00 (0.75, 1.33); p = 0.988] or the odds of re-excision [OR 0.65 (0.35, 1.24); p = 0.192].

Conclusions: Pre-operative MRI is associated with increased odds of receiving ipsilateral mastectomy and contralateral prophylactic mastectomy as surgical treatment in newly diagnosed BC patients.

Keywords: Breast cancer; Breast-conserving surgery; Magnetic resonance imaging; Mastectomy; Meta-analysis; Re-operation.

Fig 1

Models comparing surgical outcomes in breast cancer patients who had pre-operative MRI versus those who did not have MRI: study-specific and pooled odds ratios for receipt of mastectomy as surgical treatment. [Study-specific OR for Fortune-Greeley et al was based on the adjusted OR reported in that study]

Fig 2

Models comparing surgical outcomes in breast cancer patients who had pre-operative MRI versus those who did not have MRI: study-specific and pooled odds ratios for re-excision surgery in those who had breast conservation.

Fig 3

Models comparing surgical outcomes in breast cancer patients who had pre-operative MRI versus those who did not have MRI: study-specific and pooled odds ratios for positive margins in those who had breast conservation.

Fig 4

Models comparing surgical outcomes in breast cancer patients who had pre-operative MRI versus those who did not have MRI: study-specific and pooled odds ratios for ‘any reoperation’.

Fig 5

Models comparing surgical outcomes in breast cancer patients who had pre-operative MRI versus those who did not have MRI: study-specific and pooled odds ratios for receipt of contralateral prophylactic mastectomy. [Study-specific adjusted ORs were used in this analysis – see Statistical methods]

Fig 6

Models comparing surgical outcomes in patients with invasive lobular cancer who had pre-operative MRI versus those who did not have MRI: study-specific and pooled odds ratios for receipt of mastectomy as surgical treatment.

Fig 7

Models comparing surgical outcomes in patients with invasive lobular cancer who had pre-operative MRI versus those who did not have MRI: study-specific and pooled odds ratios for re-excision surgery.