Combined application of information theory on laboratory results with classification and regression tree analysis: analysis of unnecessary biopsy for prostate cancer.
BACKGROUND
The probability of a prostate cancer-positive biopsy result varies with PSA concentration. Thus, we applied information theory on classification and regression tree (CART) analysis for decision making predicting the probability of a biopsy result at various PSA concentrations.


METHODS
From 2007 to 2009, prostate biopsies were performed in 664 referred patients in a tertiary hospital. We created 2 CART models based on the information theory: one for moderate uncertainty (PSA concentration: 2.5-10 ng/ml) and the other for high uncertainty (PSA concentration: 10-25 ng/ml).


RESULTS
The CART model for moderate uncertainty (n=321) had 3 splits based on PSA density (PSAD), hypoechoic nodules, and age and the other CART for high uncertainty (n=160) had 2 splits based on prostate volume and percent-free PSA. In this validation set, the patients (14.3% and 14.0% for moderate and high uncertainty groups, respectively) could avoid unnecessary biopsies without false-negative results.


CONCLUSIONS
Using these CART models based on uncertainty information of PSA, the overall reduction in unnecessary prostate biopsies was 14.0-14.3% and CART models were simplified. Using uncertainty of laboratory results from information theoretic approach can provide additional information for decision analysis such as CART.
Department of Laboratory Medicine, Research Institute and Hospital, National Cancer Center, Goyang-si, South Korea.
Sang-Hyun
SH
Hwang
Tina
T
Pyo
Heung-Bum
HB
Oh
Hyun Jun
HJ
Park
Kwan-Jeh
KJ
Lee
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003661:Decision Support Techniques; D003663:Decision Trees; D006801:Humans; D007257:Information Theory; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000378:metabolism; D011470:Prostatic Hyperplasia / Q000175:diagnosis* / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D012372:ROC Curve; D012044:Regression Analysis; D035501:Uncertainty
D017430:Prostate-Specific Antigen