EUSOMA criteria for performing pre-operative MRI staging in candidates for breast conserving surgery: hype or helpful?

Ongoing debate regarding the value of pre-operative MRI in staging patients with newly diagnosed breast cancer has resulted from the lack of evidence on its clinical efficacy, which contrasts MRIs capability for detecting additional disease (occult on conventional imaging) in the cancerous breast. We undertook a validation study of EUSOMA criteria that recommend selection of breast conserving surgery (BCS) candidates to pre-operative MRI. We examined whether these criteria were associated with a differential likelihood of a recommendation for mastectomy. In a cohort of 200 subjects, recommended for BCS following mammography (M) and ultrasound (US), and who also subsequently had pre-operative MRI, the proportions recommended for mastectomy based on MRI, where the criterion was present versus absent were: invasive lobular cancer (17.9% versus 17.4%; p=0.87); high familial risk (14.7% versus 18.1%; p=0.82); M/US tumour size discrepancy >1cm (32.1% versus 15.1%; p=0.05); and for any of these criteria versus none (21.6% versus 14.3%; p=0.24). These findings suggest that EUSOMA criteria for selection to pre-operative MRI may be inefficient as they do not appear to differentiate those at risk of having more extensive disease and likely to receive a mastectomy recommendation, with the exception of M/US tumour size discrepancy.