Qin et al reported the PORTLARS score for evaluating a patient with rectal cancer who has undergone a low anterior resection and radiotherapy. The authors are from multiple institutions in China and members of the Chinese Radiation Intestinal Injury Research Group.
PORTLARS = post-radiotherapy low anterior resection syndrome
Patient selection: rectal cancer status post low anterior resection and postoperative radiotherapy
Parameters:
(1) pathologic N stage
(2) proximal colon for neorectum
(3) postoperative distal rectum length in cm
(4) anastomotic leakage
points for length of distal rectum =
= MAX(0,100 - (12.5 * (length)))
|
Parameter
|
Finding
|
Points
|
|
pathologic N stage
|
negative
|
16.6
|
|
|
positive
|
0
|
|
proximal colon
|
descending colon
|
0
|
|
|
sigmoid colon
|
22.8
|
|
anastomotic leakage
|
none
|
0
|
|
|
subclinical
|
21.7
|
|
|
clinical (requires an intervention)
|
35.4
|
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 174.8
value of X =
= (0.0618 * (score)) - 7.107
risk of major LARS =
= 1 / (1+EXP((-1) * X))
The authors also reported the logistic regression model:
logit(p) = 1.5283 - (1.0341 * (pLN)) - (1.4116 * (proximal colon)) - (0.7753 * (distal rectum)) + (1.3560 if subclinical leak) + (2.1861 if clinical leakage)
Performance:
• The area under the ROC curve is 0.84.
