Effects of preoperative magnetic resonance image on survival rates and surgical planning in breast cancer conservative surgery: randomized controlled trial (BREAST-MRI trial)

Abstract

Background: Breast magnetic resonance imaging (MRI) has high sensitivity in detecting invasive neoplasms. Controversy remains about its impact on the preoperative staging of breast cancer surgery. This study evaluated survival and surgical outcomes of preoperative MRI in conservative breast cancer surgery.

Methods: A phase III, randomized, open-label, single-center trial including female breast cancer participants, stage 0-III disease, and eligible for breast-conserving surgery. We compared the role of including MRI in preoperative evaluation versus radiologic exam routine with mammography and ultrasound in breast cancer conservative candidates. The primary outcome was local relapse-free survival (LRFS), and secondary outcomes were overall survival (OS), mastectomy rate, and reoperation rate.

Results: 524 were randomized to preoperative MRI group (n = 257) or control group (n = 267). The survival analysis showed a 5.9-years LRFS of 99.2% in MRI group versus 98.9% in control group (HR = 0.72; 95% CI 0.12-4.28; p = 0.7) and an OS of 95.3% in the MRI group versus 96.3% in the control group (HR = 1.37 95% CI 0.59-3.19; p = 0.8). Surgical management changed in 21 ipsilateral breasts in the MRI group; 21 (8.3%) had mastectomies versus one in the control group. No difference was found in reoperation rates, 22 (8.7%) in the MRI group versus 23 (8.7%) in the control group (RR = 1.002; 95% CI 0.57-1.75; p = 0.85).

Conclusion: Preoperative MRI increased the mastectomy rates by 8%. The use of preoperative MRI did not influence local relapse-free survival, overall survival, or reoperation rates.

Keywords: Breast cancer; Conservative breast cancer surgery; Magnetic resonance imaging; Randomized controlled trial.

Fig. 1

MRI additional findings. a Mastectomy due to a tumor 50% larger than evaluated by mammography and/or ultrasound and the breast still allows a conservative surgery. Mammography report (MMG): Hyperdense, irregular, and spiculated nodule, associated with tenuous amorphous calcifications, located in the lower outer quadrant (LOQ) of the right breast, measuring 1.8 × 2.8 cm. Corresponds to the irregular nodule in ultrasound are situated in the LOQ of the right breast, 1.9 × 1.3 × 1.3 cm. MRI report: Irregular nodule with spiculated margin, no signs of cutaneous involvement, located in the middle third of the LOQ of the right breast. Measures 3.0 × 3.0 × 2.0 cm. b Multicentricity tumor in MRI exam undetected by other methods. MMG report: focal asymmetry associated with round calcifications located in the right breast upper outer quadrant (UOQ), in agreement with an irregular nodule characterized at ultrasound in the right breast UOQ with 2.7 × 2.5 × 2.1 cm. The MRI report showed an irregular nodule with heterogeneous internal enhancement and progressive kinetic curve, placed in the posterior third of the UOQ of the right breast, measuring 4 × 3.4 × 2.7 cm. Associated with a focal clumped type enhancement with a progressive kinetic curve, with an extension of 3.1 cm anterior to it, which together measure 5.6 cm

Fig. 2

Flow chart of Breast MRI trial

Fig. 3

Local recurrence-free survival and Overall survival. a Local recurrence-free survival. b Overall survival