OBJECTIVES: A complete surgical excision is the key to successful breast-conserving surgery in patients with ductal carcinoma in situ (DCIS) of the breast. Preoperative magnetic resonance imaging (MRI) may allow decreasing re-interventions for positive margins. Our objective was to perform an economic evaluation alongside the IRCIS randomized controlled trial [NCT01112254] to determine whether preoperative MRI in DCIS is a cost-effective strategy.

METHODS: The patient population for the economic study consisted of 345 patients (173 in the MRI arm and 172 patients in the control arm). Costs were assessed from the French national health insurance perspective. Resource use were prospectively collected during a 6-month period after randomization and included all breast cancer-related hospitalizations, specialists visits, imaging procedures and biopsies, radiotherapy, transportations and sick leaves. We estimated the mean cost per patient in each arm and the cost difference between arms. Ninety-five percent confidence intervals and cost-effectiveness acceptability curve (cost per averted re-intervention for positive margin) were estimated using bootstrap replicates (n=10,000).

RESULTS: The re-intervention rate for positive margins was 20% in the MRI arm (35/173) and 27% in the control arm (47/172). The difference (MRI-control) in re-intervention rates was -7% [95% CI: -17%; 3%]. The number of re-hospitalizations was 48 in the MRI arm and 59 in the control arm. The mean cost per patient was € 9,682 in the control arm and € 9,980 in the MRI arm. The cost difference (MRI-control) amounted to € 298 [95% CI: -470; 1063]. For a willingness to pay of € 500 to avert a re-intervention, the probability of MRI strategy being cost-effective was 93%.

CONCLUSIONS: Preoperative MRI in DCIS tends to reduce re-interventions for positive margins and is likely to be a cost-effective strategy in France.