Patient selection: woman with breast cancer, axillary surgery with >= 1 lymph node removed, followed by radiation therapy
Parameters:
(1) body mass index in kg per square meter
(2) radiation therapy field group
(3) number of lymph nodes removed at surgery
points for BMI =
= (1.818 * (BMI)) - 27.27
|
Parameter
|
Finding
|
Points
|
|
radiation therapy field
|
no radiation
|
0
|
|
|
limited
|
17.8
|
|
|
extensive
|
35.6
|
|
number of LN removed
|
<= 7
|
0
|
|
|
8 to 11
|
17.73
|
|
|
12 to 15
|
35.46
|
|
|
>= 16
|
53.2
|
where:
• A limited radiation field included the supraclavicular fossa and axillary level III.
• An extensive radiation field included the supraclavicular fossa and axillary levels I to III.
total score =
= SUM(points for all 3 parameters)
Interpretation:
• minimum score: 0
• maximum score: 188.8
X =
= (0.02958 * (score)) - 4.837
probability of lymphedema =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve was 0.69 in the derivation set and 0.71 in the external validation.
