Several studies have validated the role of breast MRI surveillance in women who are at high risk for breast cancer development [5,6,7].
In particular an Italian study of Sardanelli and colleagues in 17 centres sceened 278 women,
of whom 63% were tested BRCA mutation carriers or first-degree relatives of a tested carrier.
A previous history of BC was present in 44% of the women.
Eighteen cancers were detected,
giving an MRI sensitivity of 94%,
compared with sensitivities of 59% for MX,
65% for US,
and 50% for clinical breast examination [8].
Although the sensitivity of surveillance MRI has been shown to be superior to routine MX and/or US imaging,
it is limited by lower specificity,
high false-positive rates,
and increased needs for additional imaging and/or biopsy.
Two studies reported data indicating that adding MRI to MX increased a woman’s risk of being recalled for further investigation of a false positive result approximately three to five-fold [7,9],
with the number of additional false positive recalls per 1000 screening rounds varying according to the risk of the disease in the screened population.
Both studies showed that adding MRI increased the risk of bening percutaneous biopsies by at least three-fold.
In contrast,
Kuhl and colleagues observed a smaller,
non-significant difference in the rate of bening percutaneous biopsies when MRI was added to mammography [6].
The rate of cancer detection in high-risk patients undergoin breast MRI at our institution is similar to that of large,
multicenter trials.
Adding MRI in breast cancer screening program for high-risk-women,
increased the risk of recalled for further investigation of a false positive results,
but the sensitivity of surveillance MRI has been shown to be superior to routine MX imaging (83% versus 67%) and similar to US examination.
Considering the disadvantages of breast MRI,
we have evaluated number of US second look in 4 consecutive rounds.
As expected, 6 women were recalled after the first round of MR,
1 was recalled after the second one,
3 after the third and 0 after the last round. Out of 10 recall,
3 patients (23%) had diagnosis of BC. The present study shows that,
excluding patients with cancer diagnosis the percentage of recall is reduced to the increased of the round.
In the 7 BC detected,
we also make a critical revision of previous MRI round: 6/7 breast cancer were visible as non specific enhancement focus with diameter of 3-5 mm.
In the evaluation of MRI is mandatory an expert breast radiology.
The presence of a previous round of MRI should help to recognize the appearance of focus of enhancement also of a few millimeters,
that in this population should be considered suspicious and re-evaluated with US second look,
and if this is negative these foci should be monitored with a short-term MRI and if necessary they must be submitted to cito-histological findings below MRI guide.
In summary,
MRI has replaced MX as the gold standard for screening for breast cancer among high risk women with results similar to US in our population.
Issue related to specificity and false positive results of MR is largely solved in this population in particular with the possibility to compare the examination with previous rounds and with second look US.
It is likely that in the near future,
the use of MRI will be expanded also to women at moderate risk of BC,
limited to the high cost of this procedure.