Reliability and validity of a histologic score as a marker for skin cancer chemoprevention studies.
OBJECTIVE
To develop a reliable and valid scoring system for grading skin biopsies from actinic keratosis (AK) and sun-damaged skin for use in evaluating the efficacy of skin cancer chemopreventive agents.


METHODS
A panel of dermatopathologists developed histologic criteria and diagnostic definitions for the progression of lesions from early AK to AK. The criteria were then applied to a sample of 335 histologic slides from an ongoing chemoprevention study. A 10% sample of 35 slides was reread in order to assess intrarater reliability.


RESULTS
Six of the 7 criteria demonstrated high reliability (> 85%). The total histologic score, calculated using the 6 criteria, was found to significantly differentiate between (blinded) biopsy location (normal, pre-AK, AK and adjacent to squamous cell carcinoma) and histologic diagnosis (normal, pre- or early AK, AK and squamous cell carcinoma).


CONCLUSIONS
The total histologic score, having demonstrated reliability on repeated readings and validity in its association with biopsy location and histologic score, is a reliable and valid end point for judging the efficacy of agents in skin cancer chemoprevention studies. Additional interrater reliability tests utilizing larger test sets and a rigorous statistical design should be undertaken to establish its portability.
Bozzo
Paul
P
Arizona Cancer Center, Departments of Pathology and Medicine, University of Arizona, P.O. Box 245024, Tucson, Arizona 85724-5024, USA.
Saboda
Kathylynn
K
Einspahr
Janine G
JG
Ranger-Moore
James
J
Farmer
Evan R
ER
Cockerell
Clay J
CJ
Elder
David E
DE
Bangert
Jerry L
JL
Hart
Nancy
N
Kramer
Cheryl B
CB
Alberts
David S
DS
D001706:Biopsy; D018890:Chemoprevention; D003094:Collagen / Q000528:radiation effects; D006652:Histological Techniques; D006801:Humans; D015603:Keratinocytes / Q000473:pathology / Q000528:radiation effects; D007642:Keratosis / Q000209:etiology / Q000473:pathology*; D011237:Predictive Value of Tests; D011832:Radiation Injuries / Q000473:pathology; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012878:Skin Neoplasms / Q000473:pathology / Q000517:prevention & control*; D014466:Ultraviolet Rays / Q000009:adverse effects
D003094:Collagen