Pivotal Study

As the first real-time intraoperative margin assessment system, MarginProbe is clearly unique from today’s typical tumor location and margin assessment methodologies, including frozen section, touch prep cytology, specimen radiology and specimen ultrasound.

Recently, the MarginProbe system was the subject of one of the largest randomized, controlled trials of breast cancer margins ever performed, a pivotal study of 596 patients across 21 breast cancer centers. Patients with non-palpable lesions were randomized in the OR after a standard lumpectomy was completed.

Results of the study showed a significant improvement over Standard of Care (SOC) when the MarginProbe device was used.

Device + SOC

SOC

P-value

     % change from SOC

Ability to address positive margins on the main specimen
(in patients with a positive margin)

72%

(117/163)

22%

(33/147)

<0.0001

 

 220% increase

Positive margins on the main specimen which were not addressed

15.4%

(46/298)

38.3%

(114/298)

<0.0001

60% reduction

Positive margin rate*

30.9%

(92/298)

41.6%

(124/298)

0.008

 

26% reduction

*includes patients with positive margins on shavings, which were not measured by device per protocol

This much higher level of positive margin identification was achieved with only an average of 2 extra margins removed per patient.

Margins removed per patient

Device + SOC

SOC

Difference
        Positive margin on the main specimen

3.57

1.30

2.27

        No positive margins on the main specimen

2.88

0.97

1.97

 

 

Diagnostic Performance

Current methods of margin assessment have insufficient sensitivity, as is evidenced by the high rates of positive margins reported in the literature.  Rather than make the tradeoff to eliminate specificity by shaving every margin, every time, the designers of the MarginProbe System sought to increase sensitivity, at a much smaller cost to specificity.

In the pivotal study, diagnostic performance, when evaluated margin by margin, was:

Device + SOC

SOC

Sensitivity

73.8%

33.9%

Specificity

45.1%

83.4%

 

In a development study1, when MarginProbe was compared to detailed pathology of the area measured by the sensor, the diagnostic performance, when evaluated point by point, was:

Sensitivity

Specificity

Homogeneous tissue

100%

87%

All lumpectomy tissue

70%

70%

 Data from Pappo et al. development study

For surgeons who have relied primarily on palpation or visual inspection, the performance data represents more reliable, instrument-based data to support surgical decisions. 

 

Sensitivity remains high even for very small amounts of cancer at the surface.
MarginProbe_Graph1

Data from Pappo et al. development study

Sensitivity is also high across all types of cancer:

Histopathology

N

Detected

Detection rate

IDC

87

59

68%

DCIS

35

22

63%

ILC

7

5

71%

IDC+DCIS

25

21

84%

ILC+DCIS

3

3

100%

Other

8

6

75%

Data from Pappo et al. development study

Pappo I, et al.
Epub 2009 Mar 31. J Surg Res. 2010;160(2):277-81.