Allred scoring system

Allred scoring system

A clinical instrument based on the percentage of cells that stain by immunohistochemistry for oestrogen receptor (ER) (on a scale of 0 to 5) and the intensity of that staining (on a scale of 0 to 3, for a possible total score of 8). Allred scoring stratifies a breast cancer patient’s ER status into cancers that are likely to respond to hormone therapy with tamoxifen or letrozole. As a rule, breast cancers do not respond to tamoxifen with an Allred score of < 6 or to letrozole with a score of < 3.

Allred scoring
Proportion score
0—No cells are ER +ve.
1—≤ 1% of cells are ER +ve.
2—1–10% of cells are ER +ve.
3—11–33% of cells are ER +ve.
4—34–66% of cells are ER +ve.
5—67–100% of cells are ER +ve.

Intensity score
0—Negative.
1—Weak.
2—Intermediate.
3—Strong.

Allred score
0–1—No effect.
2–3—Small (20%) chance of benefit.
4–6—Moderate (50%) chance of benefit.
7–8—Good (75%) chance of benefit.
References in periodicals archive ?
ER and PR expression status was assessed by immunohistochemistry using Allred scoring system and was compared with the clinical stage defined by The International Federation of Gynecology and Obstetrics (FIGO) staging system.
ER and PR were graded using Allred scoring system which is based on the percentage of the cells that stained by ICC on a scale of 0-5 and intensity of the staining on scale of 0-3 giving a total score of 8.
In this study, the interpretation of ER, PR, and HER2 was per the ASCO/CAP recommendations.[6] However, for ER and PR interpretation, confusion might occur between scores 2, which is negative and 3, which is positive when using Allred scoring system.[10] ICC on CB for ER showed four cases to have 2 as a total score in Allred system.
Allred scoring system was used for assessing ER positivity.