Kubo et al reported a model for predicting peritoneal seeding in a patient with an advanced gastric cancer. The authors are from the Korean National Cancer Center, Imperial College of London, Memorial Sloan Kettering Cancer Center, Hiroshi University, Hebrew University of Jerusalem, Kaplan Medical Center and California Institute of Technology.
Patient selection: advanced gastric cancer
Parameter:
(1) age in years from 10 to 90 years
(2) ASA score
(3) serum fibrinogen, standardized variable from -3 to 7
(4) gross type (Borrmann) of gastric tumor on EGD
(5) ascites on CT scan
(6) peritoneal thickening on CT scan
(7) location of primary tumor
(8) circumferential location of primary tumor (anterior, posterior, lesser curvature, greater curvature)
(9) tumor growth into wall
(10) metastases in regional lymph nodes
(11) distant metastases
points for age =
= 53.55 - (0.595 * (age))
points for standardized fibrinogen =
= (8.44 * (standardized fibrinogen)) + 25.32
|
Parameter
|
Finding
|
Points
|
|
ASA score
|
1 or 2
|
0
|
|
|
3 or more
|
33.7
|
|
gross type
|
2 (ulcer with raised margin; with clear margin
|
0
|
|
|
3 (ulcer with raised margin; thick wall without clear margins)
|
46
|
|
|
4 (no raised margin or ulcer; thickened wall without clear margins)
|
100
|
|
ascites
|
no
|
0
|
|
|
yes
|
57.5
|
|
peritoneal thickening
|
no
|
0
|
|
|
yes
|
37.6
|
|
location of primary tumor
|
middle
|
30.7
|
|
|
other (upper or lower)
|
0
|
|
circumferential location anterior
|
no
|
23.8
|
|
|
yes
|
0
|
|
circumferential location
greater curvature
|
no
|
0
|
|
|
yes
|
28.4
|
|
clinical T stage
|
tumor invades muscularis propria
|
0
|
|
|
tumor invades serosa
|
53.9
|
|
|
invades contiguous structures
|
57.1
|
|
mets in lymoh nodes
|
none
|
0
|
|
|
1 or 2 regional lymph nodes
|
66.7
|
|
|
3 to 6 regional lymph nodes
|
61.4
|
|
|
>= 7 regional lymph nodes
|
56
|
|
distant metastases
|
no
|
0
|
|
|
yes
|
37.6
|
where:
• The method of standardizing the fibrinogen is not given. A standardized fibrinogen of 0 is assigned 25 points. Standardized fibrinogen is expressed as 10^3 per µL but mass units are not specified.
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 694.4
value of X =
= (0.02214 * (score)) - 7.803
probability of peritoneal seeding =
= 1 / ( 1 + EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.86.
