133 patients were recruited in the high-risk screening program; 7 of them were excluded a posteriori because of prophylactic mastectomy.
126 patients were considered in the retrospective analysis,
99 (78.6%) of them BRCA1 and 27(21.4%) BRCA2 mutated.
They attended a total number of 636 screening events,
where a screening event was defined as an attended annual imaging protocol,
including all the imaging modalities expected by the protocol (US+MRI for patients < 35 y and FFDM+US+MRI for patients >=35 y),
or part of them.
Mean age was 43y,
range 22 -72 y.
The mean number of years of surveillance per woman was 5.0,
leading to an attendance rate of 86%.
In Table 1 a general description of study population and surveillance program outcomes is provided.
Table 1: Main data and outcomes of the annual surveillance program of BRCA1/2 high-risk women.
All 126 women were followed up at our hospital.
One breast cancer that developed within the first year of this follow-up was considered an interval cancer.
In total,
25 newly diagnosed cancers in 126 women were documented: 7 cancers were detected only by MRI,
but were biopsied by US at second look,
5 cancers were detected only by FFDM,
and 13 detected by mammography and US.
The interval cancer was found by the woman (palpable lump) and was depicted by both FFDM and US.
In Table 2,
the characteristics of cancers found in the surveillance period are reported.
Table 3: Characteristics of cancers found in the high-risk population.
Table 2: Shows the imaging modalities by which cancers were depicted.
Two of 25 cancers were missed with MRI,
but detected by FFDM as microcalcification clusters and resulted in two DCIS lesions.
An example of MRI-detected cancer is shown in Figure 1.
Fig. 1: Example of true positive in a BRCA2 carrier with negative FFDM and suspicious MRI. The mass was visible also at the second look US. It was an invasive ductal carcinoma pT1bN0.
76 of 101 suspicious findings were false positives; 43 of them underwent image-guided biopsy and remaining 33 to short-term follow-up.
Forty-two suspicious findings were suspicious with MRI (54%),
6 with FFDM (8%),
and 29 with US (38%).
Twenty-eight women were recalled in between two screening events for imaging follow-up: a total number of 33 recalls,
producing 4 US-guided biopsies,
with no cancer found.
An example of MRI false positive is provided in Figure 2.
Fig. 2: Example of false positive in a BRCA1 carrier with negative FFDM (dense breast) and suspicious MRI. The linear contrast enhancement was visible at the right side between the lower quadrants. A lesion with partially irregular margins was biopsied at the second-look US It was a benign lesion (focal sclerosing adenosis).
Comparing the overall cancer detection and the recall rate considering the annual screening events and the total number of events,
including intermediate follow-up events,
results reported in Table 4 are obtained.
Table 4